ALBERT

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Donatella Magri, Alessandra Celant, Federico Di Rita〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development and decline of alder floodplain forests and alder carrs along the Tyrrhenian coasts, in relation to sea level changes, geomorphological processes, human activity, and climate change are presented and discussed. A number of 22 pollen records, complemented by 〈em〉Alnus〈/em〉 macrofossil data, document the presence of widespread alder populations in the coastal Tyrrhenian floodplains throughout the Holocene, although with different density from one site to the other, mostly depending on local hydrological conditions. The role of climate changes in the dynamics of floodplain forests appears uncertain. In the last two centuries, major reclamation works disrupted this natural vegetation to obtain fertile plains that are now exploited for agricultural purposes, industrial activities, urban areas and related infrastructures. Only a few remnants of the original alder forests are preserved by international conservation conventions, as biodiversity reservoirs of severely endangered habitats. However, the vanished alder forests, which proved to be able to rapidly recover several times through the Holocene, may still have some potential to be restored.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Sukwoo Kim, Minseok Kim, Hyunuk An, Kunwoo Chun, Hyun-Joo Oh, Yuichi Onda〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High resolution DEMs and physical soil strength, among other factors, have significant effects on the shallow landslide instability mapping. Subsurface flow in soil mantle normally is assumed by slope parallel flow based on resolution of DEMs and, measuring soil strength, which is affected by subsurface flow within the soil mantle, is difficult in both the field and the laboratory. Thus, the aims of this study are to investigate the effect of subsurface flow by high resolution Lidar DEMs and the effect of physical soil strength attributes on shallow landslide instability mapping, respectively. In this study, two DEMs (with 1 m and 5 m resolutions) were used and, physical soil strength was calibrated using a simple subsurface hydrological concept with LiDAR and field survey data in order to quantify the influence of soil strength on shallow landslide instability mapping. To this end, various field surveys were performed at Woomyeon Mountain, Seoul, Republic of Korea, where shallow landslides occurred in 2012. The physical shallow landslide stability (SHALSTAB) model were applied. The modified success rate (MSR) method were applied to assess the predicted results. In the first series of simulations, using the two DEMs and experimentally derived soil strength values, relatively low MSR values of 0.42–0.468 for the 1 m DEM and 0.42–0.47 for the 5 m DEM were recorded. In the second series of simulations, using soil strength calibrated using a simple theoretical approach, the MSR for the 1 m DEM was 0.78–0.823 and the MSR for the 5 m DEM was 0.723–0.80. These results indicated that soil strength had a more important role in shallow landslide instability mapping than assuming subsurface flow by topographic resolution. Therefore, it may be useful to apply field-collected soil strength data using hydrological concepts to improve the accuracy of predictive models based on high-resolution surface data.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): José Miguel Reichert, André Pellegrini, Miriam Fernanda Rodrigues, Tales Tiecher, Danilo Rheinheimer dos Santos〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tobacco is produced in Brazil mainly by small farmholders, on shallow soils on steeplands or on sandy soils, usually under intense soil tillage and lacking soil conservation measures, which can result in large losses of water, soil and nutrients such as P and K. We studied soil management systems for tobacco cropped using animal traction, on shallow soil on steeplands. On a Leptosol, we evaluated conventional tillage (CT), minimum tillage after fallow (MTf), minimum tillage after oat (MTo), no-tillage without ridge (NT), no-tillage with ridge (NTr) and no-tillage with consolidated ridge (NTrc), in a completely randomized blocks design with three replicates. Runoff plots of 1.2 m〈sup〉2〈/sup〉 were used to determine water and soil loss by runoff, and total and soluble P and K losses in eight rainfall events during the tobacco crop cycle. Oat cultivation prior to tobacco provided higher dry-mass mulch production and the lowest proportion of exposed soil and rocks in NTr, NTrc and NT systems. The losses of water and of P and K in the soluble forms during the storm rainfall events evaluated were lower for NT management compared to the other treatments. Total soil loss for the monitored rainfall-events was 15 and 16 Mg ha〈sup〉−〈/sup〉〈sup〉1〈/sup〉 for CT and MTf management, and it was reduced about five times for MTo, NTrc and NTr treatments. However, the lowest soil loss was observed for NT (0.2 Mg ha〈sup〉−〈/sup〉〈sup〉1〈/sup〉). This same trend was observed for total losses of P and K, where NT reduced about 97 and 57 times the losses of these nutrients compared to CT. Therefore, these results show that conservation managements such as no-tillage or minimum tillage associated with winter cover crops without grounding of tobacco seedlings may be effective to reduce soil losses along with P and K adsorbed in the soil. However, reduction of losses of water, soluble and total P and K was only effective combining no-tillage with no ridge construction and winter cover crop.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Quanchao Zeng, Peilong Jia, Ying Wang, Honglei Wang, Chengcheng Li, Shaoshan An〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil fungi play critical ecological roles in terrestrial ecosystem function, soil formation and element cycles. However, the biogeography of soil fungi in the forest ecosystem is poorly understand, especially in arid or semiarid areas. Here, a regional scale study in an arid area was conducted on the Loess Plateau to illustrate the geographic distributions of soil fungi and their driving forces. The results showed that Ascomycota, Basidiomycota and Zygomycota were the most dominant phyla in 24 sample sites. Fungal Shannon diversity and OTUs richness were significantly correlated with mean annual precipitation (MAP), total soil nitrogen (TN), ammonium nitrogen (NH4N) and soil organic carbon (SOC) levels. The decay-curve analysis demonstrated that soil fungal Bray-Cutis dissimilarities were significantly regressed with geographic distance, revealing that the soil fungal community structure was affected by historical factors. Variation partitioning analysis revealed that the soil properties (15%) contributed more to the fungal community variations than geographic distance (9%). Additionally, there were many predictors of soil fungi geography that were not detected. These results suggest that the fungal geography on the Loess Plateau is mainly regulated by soil properties or other unmeasured variables. Such findings advance our understanding of fungal diversity patterns on the Loess Plateau, which will help us better understand the functions and services in underground ecosystems in arid areas.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Gökhan Demir〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present study, landslide susceptibility assessment for a part of the North Anatolian Fault Zone between Reşadiye and Koyulhisar townships has been determined using index of entropy (IOE) and frequency ratio (FR) models within geographical information system. The landslide inventory map has been created in the study area. Altogether 91 landslides were mapped and 63 (69%) were randomly selected for modelling, with the remainder (28, 31%) used for validating the models. The landslide-conditioning factors, including slope degree, aspect, elevation, distance to faults, distance to streams, distance to road were selected. Subsequently, landslide susceptibility maps were produced using frequency ratio and index of entropy models. For verification, the receiver operating characteristic (ROC) curves were drawn and the areas under the curve (AUC) were calculated. The verification results showed that FR model (AUC = 75.71%) provided slightly better predictions than the IOE (AUC = 75.43%) model. According to the FR, about 32.54% of the study area is located within high to very high susceptibility classes of landslides. The interpretation of the susceptibility map indicates that distance to streams, distance to road and distance to fault play major roles in landslide occurrence and distribution in the study area. The landslide susceptibility maps like the one produced in this study should provide a valuable tool for the use of planners and engineers for reorganizing or planning new road and domestic constructions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): B. Oliva-Urcia, A. Moreno〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work presents the paleoenvironmental reconstructions from three mountaineous lakes located in northern Iberia. The results from the three lakes are compared and completed with classical magnetic analyses in order to detect the influence of different processes on the record and preservation of magnetic properties. The lakes are located in the Cantabrian Mountains, Enol Lake, and in the Pyrenees, the Marboré Lake and Basa de la Mora Lake and share a similar composition of their catchment areas, dominated by limestones, although in Basa de la Mora ophites are also present. The organic matter content differs, being Enol the one with the highest organic carbon values. Redox indicator (Mn/Fe) is higher and more variable in Basa de la Mora Lake, whereas in Enol and Marboré Lakes steadily increases towards the top of the sequences. New and revisited results unravel the significance of the magnetic changes respect to the geochemical and sedimentological variations found in the geological record. Strong magnetic magnetite dominates the magnetic properties variations, with detrital and new grains formed due to diagenesis and changes in the redox conditions -more aerobic-, which alter the concentration of magnetic minerals during the Late Pleistocene and Holocene. The new and revisited data underlines their value as environmental and paleoclimate archives.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Diego Fernandes Terra Machado, Michele Duarte de Menezes, Sérgio Henrique Godinho Silva, Nilton Curi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil legacy data are important sources of soil information, especially when dealing with limited resources. In countries with high geographical diversity and few financial resources, such as Brazil, they represent an economical alternative to obtaining soil spatial information in higher resolution. By retrieving the soil scientist's knowledge, it can be used as guidance for knowledge-based digital soil mapping approaches. In this sense, this work aimed to evaluate Rule-Based Reasoning and Case-Based Reasoning knowledge-based approaches to predict soil types up to the third categorical level (U.S Soil Taxonomy) in a non-sampled area, by retrieving and then extrapolating the information of a detailed soil legacy map, from a reference area. The study was carried out in Minas Gerais state, Southeastern Brazil. The methodology includes three main steps: i) knowledge acquisition; ii) soil inference; and iii) accuracy and uncertainty assessment. For the validation, 23 independent samples were chosen by means of the Regional Random method, and the accuracy was assessed by Kappa index, Overall Accuracy, Users', and Producers' Accuracy. The uncertainty was evaluated through entropy and exaggeration. A total of 24 inference models were obtained with the Case-Based Reasoning approach, in which the best model had an overall accuracy of 61% and a Kappa index of 0.52. The Rule-based reasoning approach performed better, with an overall accuracy of 82% and 0.75 for Kappa index. These approaches generated a higher accuracy soil map for an unmapped area that was 15 times larger than the reference area and at lower cost.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 181〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Xuejuan Bai, Baorong Wang, Shaoshan An, Quanchao Zeng, Haixin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the “Grain for Green” project goes on in the Loess Plateau, some drawbacks, such as the low survival rate, the appearances of dry soil layers and little old trees are appearing, especially for introduced tree species. Ecological stoichiometry, which indicates the balance of elements and the flow of energy, plays a vital role in exploring biogeochemical cycling in ecosystems. To investigate the carbon (C), nitrogen (N) and phosphorus (P) balance and flow of energy, the stoichiometry characteristics and stoichiometry homeostasis for introduced and natural forests on the Loess Plateau, four typical forests were selected, including three introduced forests composed of 〈em〉Robinia pseudoacacia〈/em〉 (〈em〉R. pseudoacacia〈/em〉), 〈em〉Pinus tabuliformis〈/em〉 (〈em〉P. tabuliformis〈/em〉) and 〈em〉Platycladus orientalis〈/em〉 (〈em〉P. orientalis〈/em〉) and a natural forest composed of 〈em〉Quercus wutaishansea〈/em〉 (〈em〉Q. wutaishansea〈/em〉) and the C, N and P in the plant-litter-soil system were measured. The results showed that the C, N and P contents and C:N:P in leaves, branches, fruits, litters and soils varied widely and were influenced strongly by forest species. The N content in 〈em〉R. pseudoacacia〈/em〉 leaves, branches, fruits and litters and the soil C, N and P contents in 〈em〉Quercus wutaishansea〈/em〉 were higher than those in other forest species. The soil C:N:P stoichiometry in 〈em〉Quercus wutaishansea〈/em〉 was higher than that in introduced forest species, while the reverse was found for plant tissues and litter C:N:P. According to the leaf N:P, with the exception of 〈em〉R. pseudoacacia〈/em〉, growth of the other three forest species was limited by N. The N, P and N:P homeostasis exist in trees, especially in 〈em〉Quercus wutaishansea〈/em〉, forest species and plant tissues had significant effects on the strength of homeostasis. Overall, the results of C, N and P content and stoichiometric homeostasis revealed that the natural forest was more adaptable to the arid environment in the Loess Plateau compared to the introduced forests.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Erdem Yılmaz, Murad Çanakcı, Mehmet Topakcı, Sahriye Sönmez, Bora Ağsaran, Zeki Alagöz, Sedat Çıtak, Dilek Saadet Uras〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this research, the effects of amendments of vineyard (〈em〉Vitis vinifera〈/em〉) pruning residue (VPR) into soil (Typic Xerofluvent) by two different soil tillage (disk harrow and rotary tiller) on aggregate formation (AgF), aggregate stability (AgS) and organic carbon (OC) content of macro– and micro–aggregate sizes were investigated. For this purpose, an experiment was conducted during 2011 to 2012 in the Batı Akdeniz Agricultural Research Institute station in Turkey. VPR was incubated for two years in soil after having been chopped by the power take off (PTO) driven pruning residue chopper. At the end of the incubation period, the effects of VPR on soil AgF, AgS, and OC content in different aggregate scales (0.05–0.25 mm, 1–2 mm) were determined by using soil samples taken at the depths of 0–10 cm and 10–20 cm. After pruning in every two years, VPR were applied to soil at the amendment rate of 7233 kg ha〈sup〉−1〈/sup〉 based on the dry matter. The amount of macro–aggregate in all sizes, except for 〉4 mm, at both soil depths increased in the second year comparing to first year by the VPR amendment with rotary tiller. There were significant differences for AgS between 2011 and 2012. AgS decreased in some micro–aggregates and in most macro–aggregates in pruning amendments with rotary tiller at 0–10 cm soil depth. It was also determined that OC content of micro (0.05–0.25 mm) and macro (1–2 mm) soil aggregates decreased after the amendment of VPR in the second year. The results of this study suggest that the use of VPR may offer benefits for soil structural development and soil conservation, whereas the soil tillage could have a negative effect on carbon conservation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Yi Wang, Hexiang Duan, Haoyuan Hong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, an effective kernel-based learning framework for landslide susceptibility mapping (LSM) is presented through an implementation of support vector machines (SVMs) with different composite kernels. Kernel-based classification methods are very popular in statistical classification and regression analysis because they can effectively address intractable issues such as the curse of dimensionality, limited known samples and noise corruption. The most representative of such methods is the SVM technique. Although SVMs have recently been widely used in LSM, they were defined using only the attribute value of each influencing factor and did not consider the high dependency between the adjacent vector-valued grid cells. This caused a labelling uncertainty. To solve this problem, it is necessary to combine both the influencing factor's attribute features and spatial dependency information in the SVM. In this work, we present two forms of composite kernels to combine the two aforementioned types of information: 1) constructed through a single kernel with stacked vectors; 2) built through summation kernels under different restrictions. The main advantages of the proposed framework are twofold. First, the integration of the two types of information can improve the predictive capability of the SVMs by removing the isolated class noise in the LSM results. Second, other useful information can be extracted from the spatial domain, such as the structural features of grid cells within and outside of landslide areas. The SVM comparisons were based on data from Yongxin County, China, containing 364 past landslide occurrences that were separated randomly into a training set (70%) and a validation set (30%). The geo-environmental setting of the study area was analysed and sixteen influencing factors were selected. The validation of these SVMs was performed using the receiver operating characteristic (ROC) and the area under the ROC curve (AUC). Experimental results demonstrate that all the SVM-based landslide susceptibility maps have similar spatial distributions upon visual inspection. Specifically, the mountainous zones in the north and south of the study area are characterized by high and very high susceptibility values, respectively, whereas the central part of the study area is categorized as the least susceptible zone. Meanwhile, the composite kernel-based learning framework can achieve a better prediction accuracy than the original SVM. From quantitative analysis, the four SVMs with a summation kernel obtain the AUC values above 0.8900, which is 0.0117 higher than that of the original SVM. Furthermore, a weighted scheme in the summation kernel can result in AUC values that are at least 0.0014 higher than a directional scheme.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Zahra Rasaei, Patrick Bogaert〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉This paper tackles the issue of spatially predicting soil classes by combining at best soil information coming directly from legacy soil profiles with soil information indirectly obtained from spatial covariates. Based on Multinomial Logistic Regression (MLR) and Bayesian Maximum Entropy (BME) models, we first show that prediction models easily lead to very different soil maps while having at the same time quite comparable global performances. By relying afterwards on a Bayesian data fusion (BDF) approach, we emphasize the benefit of combining the output of these two prediction models in order to get a single final map that combines the major spatial features of the MLR and BME maps while at the same time improving the quality of the predictions.〈/p〉 〈p〉The advocated methodology is illustrated with the mapping of World Reference Base (WRB) soil classes over a 10,480 km〈sup〉2〈/sup〉 area located in Iran. A set of 390 soil profiles allowed us to assign the WRB soil classes at these locations. In parallel, a set of potentially related covariates were computed from a 90 m resolution digital elevation model. Using MLR and BME models, predictions were obtained separately at the nodes of a 90 m resolution grid. Even if the performances of the MLR and BME models compare well, it is shown that a BDF procedure that combines both results yields improved performances, with spatial features that are a balanced combination of those found separately on the MLR and BME maps.〈/p〉 〈p〉These results emphasize the benefit of data fusion in order to improve the quality of the final map. Though the study was conducted here using MLR and BME models for predicting WRB soil classes, we believe this methodology and the corresponding findings are relevant when it comes to handle the results of spatial prediction models that are making use of distinct information sources in other soil science mapping contexts.〈/p〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Yu Liu, Zeng Cui, Ze Huang, Manuel López-Vicente, Gao-Lin Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The accurate measurement of soil infiltration rates is a challenging task in hydrological studies, as they are governed by complex interactions between the plant and soil components. To explore the effects of plant roots and soil moisture (SM) on infiltration process, an automatic measurement system based on a point source device was used to determine infiltration rates at different cultivated grasslands (leguminous, gramineous and mixed) in an arid region of China. The results showed that SM and plant roots significantly affected the infiltration process at different stages in the three grasslands. The soil infiltration rates were negatively correlated to SM, but a positive correlation was observed with the below-ground biomass (BGB). SM was the main factor influencing the infiltration rates in the initial stage of infiltration, whereas both SM and BGB determined the steady-state infiltration rates. The influence of the combined effects of SM and plant roots decreased over infiltration time. The decreased rate of determining coefficient showed that SM was more influent than plant roots. These results may contribute to interpret the observed higher soil infiltration capacity in the leguminous grasslands than in the gramineous and the mixed grasslands, and were conducive to better understand the effects of plant and soil properties on infiltration processes in arid areas.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Gabriel Spreitzer, Joseph Gibson, Max Tang, Jon Tunnicliffe, Heide Friedrich〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Large wood (LW), delivered to the river channel in the course of commercial forest harvesting, or generated during natural events, can be mobilised during floods. The movement of wood along the river corridor involves complex cycles of recruitment, mobilisation, transportation and deposition. These processes are affected by the size, buoyancy, roughness and complexity of the wood components, as well as the relative spatial density and the character of the channel boundary elements. In order to understand the probabilistic behaviour of woody elements within the fluvial system, it is important to be able to characterise the timing, mechanisms and duration of the various phases of wood transport. Due to a lack of suitable sensing technology, a detailed understanding of LW recruitment, transport and accumulation processes has thus far been elusive. In this study we introduce a technique using a nine-degrees of freedom (9-DoF) sensor embedded in a ‘SmartWood’ dowel that shows strong potential for measuring and recording LW movement. The SmartWood assembly comprises an integrated sensor with an inertial measurement unit (IMU), accelerometer, gyroscope and magnetometer, installed in a wooden dowel that is scaled to represent a tree stem in the flume. The sensor is able to record the many different motions of LW transport. The sensor-tagged wood dowel is density-compensated, with a specific weight of 0.5 g·cm〈sup〉−3〈/sup〉. A series of verification and experimental tests was carried out to evaluate the applicability of this new technology for LW research and is presented herewith. Experiments were conducted in a 6.3 m long and 1.5 m wide flume with sinuous channel course and mobile gravel bed conditions, with a discharge of up to 10 l·s〈sup〉−1〈/sup〉. We show that LW movement during transport, particularly starting, rolling, yawing and stopping processes, but also LW impacts, can be quantified within a flume environment. These findings can be further developed to obtain the translational movement behaviour of LW, which is needed to refine probabilistic models of downstream trajectories. Understanding complex LW movement is essential for informing freshwater and forestry management guidelines.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Qingtao Lin, Qian Xu, Faqi Wu, Taotao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wheat (〈em〉Triticum aestivum〈/em〉 L.) is widely planted on China's Loess Plateau, where severe soil erosion mainly occurs on sloping farmlands. However, whether wheat regulates runoff and sediment in this region is not completely understood. This study investigated the effects of wheat for regulating runoff and sediment across different slope gradients and rainfall intensities in the Loess Plateau region. The experimental design included six growth stages of wheat (tillering, early stem extension, late stem extension, heading, ripening and stubble stage), five slope gradients (8.7, 17.6, 26.8, 36.4 and 46.6%), and three simulated rainfall intensities (60, 90, 120 mm h〈sup〉−1〈/sup〉). The effects of wheat were divided into three parts: delayed runoff generation, reduced runoff, and reduced sediment. Wheat's performance was assessed using time to runoff, initial loss of rainfall, runoff volume, sediment yield, time delay benefit (TDB), runoff reduction benefit (RRB), and sediment reduction benefit (SRB). The results showed wheat excelled at regulating runoff and sediment. From the tillering to ripening stage, wheat reduced the runoff by 43.8–83.4% and the sediment by 86.7–98.2% when compared with bare ground; even wheat stubble was able to reduce runoff (by 35.7%) and sediment (by 68.2%). Values of TDB, RRB, and SRB for wheat were all directly proportional to its vegetation coverage and inversely proportional to the slope gradient. Similarly, wheat's TDB and RRB were inversely proportional to rainfall intensity but its SRB was not significantly influenced by it. Since their SRB values always exceeded the RRB, both wheat and stubble were found more effective at reducing sediment than reducing runoff. Vegetation coverage was the main factor affecting the TDB, RRB, and SRB of wheat, in that greater coverage particularly decreased the sensitivity of RRB and SRB to changes in the slope gradient. In conclusion, wheat is suitable for cultivation in erosion-prone areas with abundant sloping farmland resources and heavy rainstorms.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Francisco Cellone, Eleonora Carol, Luigi Tosi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Groundwater geochemistry and dynamics are both among the main controlling factors of environmental features in wetlands. Coastal wetlands in particular are complex environments in which groundwater geochemistry is linked to a large number of controls, such as tidal action, landforms and interactions between groundwater and surface water. The Parque Costero del Sur Biosphere Reserve is part of a larger wetland zone that extends along the right margin of the Río de la Plata estuary. The environmental characteristics present in such area are strictly connected to the geomorphological setting of the coastal plain. The aim of this study is to understand the hydrogeochemical processes which determine groundwater quality in this biosphere reserve. Major ions and environmental isotopes of groundwater were analyzed together with water balances, water table measurements and a geological and geomorphological characterization of the coastal plain in order to analyze the hydrogeochemical and hydrodynamic processes present in the wetland. Results point out that the groundwater hydrogeochemical and hydrodynamic characteristics vary over the different landforms that form the Río de la Plata coastal plain, with particular chemical facies for each one. The principal hydrogeochemical mechanisms acting in groundwater are controlled by processes which include rainfall recharge, dissolution of CO〈sub〉2(g)〈/sub〉, carbonates, halite and gypsum, and Na〈sup〉+〈/sup〉/Ca〈sup〉+2〈/sup〉 exchange. Water is one of the main conditioning factors in wetlands and this study is the first attempt to understand the mechanisms that rule groundwater geochemistry in this remote area. This research contributes to a better understanding both the hydrology and hydrogeochemistry of the biosphere reserve and future investigations will benefit from our results. In particular, this work provides the basic knowledges on surficial water - groundwater interaction necessary to develop an integrated coastal management plan aimed to guarantee the ecosystem protection through a sustainable use of the natural reserve.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219302851-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Juan-José Ibáñez, Eric C. Brevik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉There has been considerable interest in geodiversity and pedodiversity studies over the last approximately 30 years. Pedodiversity is considered part of geodiversity, but in practice they involved different experts and traditions. There are many common aspects that could be shared by all natural diversity studies, however, these common aspects have not been adequately studied and debated. Quantitative techniques that were developed and refined by biodiversity researchers over multiple decades of biodiversity studies should also be applicable to geodiversity and pedodiversity studies. Soil scientists studying pedodiversity followed the same techniques as mathematical ecologists, but geologists studying geodiversity focused on the implementation of proposals aimed at preserving geological heritage and popularising it among the general public. Therefore, pedodiversity and geodiversity diverged and it is not currently possible to compare the results of geodiversity and pedodiversity research. To reach a point where these research results could be compared, it will be necessary to (i) follow uniform mathematical procedures in both these fields and their subfields and (ii) develop universal taxonomies that will be followed for each of the natural resources (fossils, landforms, minerals, soils, etc.) being investigated. Geodiversity studies should move beyond the objective of proposing projects to preserve natural areas of geological value for economic and social purposes (geoparks, geotourism) and extend to attempts to quantify and compare biotic and abiotic diversity and its consequences. If we want to move forward, with a view to achieving a more mature discipline and a true new paradigm, both communities of experts must act synergistically.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Honghu Liu, Feng Qian, Wenfeng Ding, José A. Gómez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study integrated 3D scanner measurement techniques with hydrological analysis to study the evolution of gullies developed in the deep weathering (granite) in the subtropical climate of southern China. Two gullies were repeatedly measured using a 3D laser scanner over a 7.5-year period from 2009 to 2016. The measurements with sub-centimeter accuracy indicated that gully head retreat was the dominant process in the gully development, with a mean rate of 0.46 and 1.10 m yr〈sup〉−1〈/sup〉 for gully A and B respectively. To explore the relationship between gully head retreat (GHR) and hydrologic variables, rainfall with three different thresholds, rainfall erosivity and runoff depth were calculated using different methods. Statistical analysis showed a significant correlation between GHR rates and cumulative erosive rainfall depth with a daily rainfall threshold 〉25 mm. Hydrological analysis and field observations suggested that gully head retreats mainly result from mass movement triggered by gravity and soil saturation, although water erosion might also play a role in destabilizing the already unstable gully slopes. This study has implications for restoration of gullies in the area, which requires techniques that go beyond a mere reduction of runoff contribution to gully systems. Further studies are needed to gather more data on the evolution and sediment delivery of gullies, to prove the hypothesis of gravity-driven gully headcut development, and to explore more effective gully restoration techniques.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Wojciech Szymański, Wojciech Maciejowski, Krzysztof Ostafin, Wiesław Ziaja, Mateusz Sobucki〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Climate warming that began after the Little Ice Age (LIA) and glacier recession due to this warming are responsible for exposure of new areas, which previously had been covered with an ice mass in many parts of the world. Areas newly abandoned by glaciers are sites where primary plant succession and development of soil cover occur. The main aim of this study was to determine impact of parent material, vegetation cover, and site wetness on spatial variability of physical and chemical properties of surface soil layers in the oldest parts of proglacial areas of small and rapidly retreating glaciers such as Kambreen, Bevanbreen, and Coryellbreen, which are located along the northeastern coast of Sørkappland (SE Spitsbergen). Surface soil samples (up to a depth of 10 cm) were collected from sites, which differed in terms of the parent material of the soil (glaciofluvial deposits, glacial till), vegetation cover (bare soils, initial tundra vegetation, moss tundra vegetation), and site wetness (dry, moist, wet). Physical and chemical soil properties such as content of sand, silt, clay, TOC, TN, Si, Al, Ca, Mg, K, Na, P as well as soil pH and soil EC were determined. The obtained research results indicate that the studied surface soil layers are characterized by very high spatial variability of physical and chemical properties. The different parent material of soil (glacial till and glaciofluvial deposits) in the studied proglacial areas affects particle-size distribution, soil pH, soil EC, and content of TN, Ca, and Na. The surface layer of soils developed from glacial till has a finer texture, lower mean soil pH and EC, lower mean content of Ca and Na as well as higher mean content of TN relative to the surface layer of soils formed from glaciofluvial deposits. Vegetation cover, which is very sparse in the study area, has a very low impact on the variability of the properties of the studied surface soil layers. A comparison of bare soils with soils covered with initial and moss tundra vegetation communities indicates that only the more dense and best developed moss tundra vegetation community affects the higher mean content of TOC and TN in the soil. Site wetness is the most important among the studied three soil-forming factors affecting the spatial variability of the physical properties (particle-size distribution) and chemical properties (soil EC, content of TOC, TN, Si, Al, Mg, K, P) of the surface layer of the studied soils. Soils occurring at dry and moist sites are characterized by very similar physical and chemical properties, while soils occurring at wet sites exhibit significantly higher mean soil EC and higher mean content of the sand and Si as well as significantly lower mean content of TOC, TN, silt, clay, Al, Mg, K, and P.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Xiaomeng Yao, Bo Xiao, Giora J. Kidron, Kelin Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Biocrusts are widely distributed throughout the world in dryland ecosystems, but their respiration rate (〈em〉R〈/em〉〈sub〉s〈/sub〉) and responses to soil temperature and mositure have not yet been fully investigated. In a semiarid region of the Loess Plateau in China, the 〈em〉R〈/em〉〈sub〉s〈/sub〉 of moss-dominated biocrusts was continuously (104 days) measured in summer through an automated soil respiration system, and their relationships with soil temperature and moisture at 2, 5, and 10 cm depths were intensively analyzed. The results showed the biocrusts had 115% higher (〈em〉t〈/em〉 = −3.82, 〈em〉P〈/em〉 〈 0.001) 〈em〉R〈/em〉〈sub〉s〈/sub〉 during day and 44% higher (〈em〉t〈/em〉 = −10.22, 〈em〉P〈/em〉 〈 0.001) 〈em〉R〈/em〉〈sub〉s〈/sub〉 during night as compared with the underlying soil; they averagely increased 〈em〉R〈/em〉〈sub〉s〈/sub〉 by 81% (2.52 vs. 1.39 μmol m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉) across day and night. More specifically, the 〈em〉R〈/em〉〈sub〉s〈/sub〉 of biocrusts ranged from 0.33 to 6.33 μmol m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 in wet conditions (soil moisture ≥ 0.15 cm〈sup〉3〈/sup〉 cm〈sup〉−3〈/sup〉) and 0.27 to 2.83 μmol m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 in dry conditions (soil moisture = 0.05 cm〈sup〉3〈/sup〉 cm〈sup〉−3〈/sup〉), with a daily mean of 2.11 μmol m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉. Particularly, in wet conditions the 〈em〉R〈/em〉〈sub〉s〈/sub〉 of biocrusts had positive responses to increasing temperature, and their relationship was well fitted with an exponential function (〈em〉R〈/em〉〈sup〉2〈/sup〉 ≥ 0.44; 〈em〉P〈/em〉 〈 0.001), with a 〈em〉Q〈/em〉〈sub〉10〈/sub〉 value ranging between 1.73 and 2.08. Similarly, the 〈em〉R〈/em〉〈sub〉s〈/sub〉 of biocrusts was positively correlated with soil moisture, but their relationship was not well fitted with the quadratic function (〈em〉R〈/em〉〈sup〉2〈/sup〉 ≤ 0.22). A model based on the soil moisture and temperature at 2 cm depth performed much better (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.53; 〈em〉P〈/em〉 〈 0.001) with 〈em〉R〈/em〉〈sub〉s〈/sub〉 than that based on the soil moisture and temperature at 5 or 10 cm depth or even air temperature. In conclusion, moss biocrusts made a significant contribution to soil respiration in semiarid ecosystem, firstly (and directly) due to the rich and diversified microbial communities in biocrust layer and secondly (and indirectly) due to the biocrust effects on soil temperature and moisture regimes. The temperature and moisture at 2 cm depth (biocrust layer) should be employed with a higher priority in simulating 〈em〉R〈/em〉〈sub〉s〈/sub〉 of biocrusted surfaces, rather than the commonly used soil depth (5 cm) in estimating 〈em〉R〈/em〉〈sub〉s〈/sub〉 of the ordinary soil without biocrusts.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219303376-ga1.jpg" width="272" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Xiaoyan Zhao, Kai Hu, Xin Liao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Granitoid saprolites, formed from the chemical weathering of granitoid rocks, contain relict fractures. However, saprolites may be considered as homogeneous soils because these relict fractures are not as visible as those in rock masses. The presence of these fractures is not as widely accepted as those that occur in stiff and expansive clays, while they can play an important role in slope excavation. In this study, the centrifugal modeling technique is employed to verify the presence of relict fractures in granitoid saprolites by demonstrating their effect on the displacement and force induced by excavation in cut slopes. Centrifugal tests are carried out using four slope models, one homogeneous and three fracture-containing, and the displacement and force induced by excavation are monitored. A comparative analysis of the results for different models shows that the presence of relict fractures has a significant effect on the excavation-induced behavior of cut slopes. The displacement and force generated during centrifuging are distinctly larger in the fracture-containing models than in the homogeneous model, particularly for the model with outward-dipping fractures. Experimental results are used to confirm the presence and mechanical implications of relict fractures in granitoid saprolite slopes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Boris Kryštufek, Giovanni Amori, Gabriel Chişamera〈/p〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Changxing Shi, Yuanyuan Zhou, Xiaofei Liu, Xiongbo Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The base level is one of the key factors controlling river evolution. In the Yellow River mouth, a base-level rise takes place not only because of a relative sea-level rise, but also as a consequence of the increasing of river channel length associated with the large progradation rate of the delta. A change in river length results in a change in the gradient (slope) of the mouth channel, which further leads to a riverbed aggradation/degradation or a water level change at the deltaic apex. This process is principally associated with the morphodynamic backwater effect. The consequent water level change can be considered as a base-level change of the Yellow River. In this work, a relation was constructed between the water level at the deltaic apex and the riverine water and sediment inputs, as well as with the gradient of the mouth channel in the progradation period of each deltaic lobe. Also, for disclosing the importance of the base-level change due to variations of mouth channel length, it was estimated and compared with the relative sea-level change in the past decades, and for predicting the water level at the deltaic apex, the relation between mouth channel length and cumulative riverine sediment input was investigated. It was found that in the period 1953–2016, the base-level changes associated with variations of the mouth channel length could be larger than 1 m, or even larger than 2 m in one year, with a conservatively estimated annual mean of 34.8 mm/a, which is much larger than the relative sea-level change of 7.0 mm/a in the Yellow River mouth. The mouth channel length is closely and linearly related to the cumulative sediment discharge of the Yellow River. The relation for calculating the water level at the deltaic apex was found to be capable of giving a reliable result with the riverine water and sediment inputs, the relative sea-level, and the mouth channel length estimated from cumulative riverine sediment discharge. This relation was also used to estimate the equilibrium gradient of the mouth channel for sediment transport. The results show that after the year 2000, the equilibrium gradient has remained smaller than the actual gradient of the mouth channel, and both gradients decreased continuously with the decrease of riverine sediment inputs, but their values were becoming closer to each other. It is highly possible that the water level at the deltaic apex will be raised by the increase in sediment discharge of the river in the future.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Yang Yang, Bingru Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Caragana korshinskii〈/em〉 shrubs are widely planted in desert steppe of Northwest China to mitigate desert encroachment. Soil nutrients and stoichiometries reflect the cycling of soil organic matter in ecosystems. Thus, there is a dynamic balance between soil nutrients and stoichiometries due to the establishment of 〈em〉Caragana〈/em〉 shrubs in this region. Here, soil nutrients and stoichiometries were characterized with different planting densities of 〈em〉Caragana〈/em〉 shrubs (HD, high density, 4530 bundle/hm〈sup〉2〈/sup〉; MD, mid density, 3670 bundle/hm〈sup〉2〈/sup〉; LD, low density, 2560 bundle/hm〈sup〉2〈/sup〉) to explore how the planting of 〈em〉Caragana〈/em〉 shrubs affects soil nutrients and stoichiometries in desert steppe of Northwest China. The results showed that soil available phosphorus (AP) and soil total phosphorus (TP) had no significant differences between LD and control (CK) (〈em〉p〈/em〉 〉 0.05). Further, soil organic carbon (SOC), soil total nitrogen (TN), and soil alkali-hydrolyzable nitrogen (AN) followed the order of HD 〉 MD 〉 LD 〉 CK, indicating that the planting of 〈em〉Caragana〈/em〉 shrubs had an increasing effect to soil nutrients, with the exception of AP and TP (〈em〉p〈/em〉 〈 0.05), and the increasing effect gradually died down along soil profile. In addition, the planting of 〈em〉Caragana〈/em〉 shrubs significantly affected soil stoichiometries. Specifically, soil N/P and C/P gradually increased with soil depth with fluctuation, while soil C/N decreased with soil depth. Besides, soil water content (SW), AP, AN, and SOC had strong positive effects on soil C/N, while they had strong negative effects on soil C/P and N/P, highlighting the importance of soil properties in determining soil stoichiometries. Overall, our results indicated that planting 〈em〉Caragana〈/em〉 shrubs can improve levels of soil nutrients, and HD can be considered the optimal planting density for vegetation restoration in desert steppe. Nevertheless, the threshold of the planting density most favorable for the special climates must be identified through further study in this region.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): A-Xing Zhu, Yamin Miao, Junzhi Liu, Shibiao Bai, Canying Zeng, Tianwu Ma, Haoyuan Hong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The absence data (samples) for landslide susceptibility mapping using data-driven methods are not available directly and often approximated by locations where no landslides have occurred. The existing methods for generating absence data cannot quantify the reliability of candidate absence data and thus such data reduce the quality of prediction. In this paper, a new approach to absence data generation, referred to as similarity based sampling, was proposed for landslide susceptibility mapping using data-driven methods. First, the reliability of candidate absence data is quantified based on the dissimilarity in environmental conditions (covariate conditions) between the absence data and the presence data (which are the landslide occurrences). The absence data whose reliability value is higher than a given threshold were selected to be used. The proposed approach was validated through its application to three data-driven methods (i.e. logistic regression, support vector machine and random forest) for landslide susceptibility mapping. A case study was conducted in the Youfang catchment in southern Gansu Province of China. Ten groups of absence data were generated each corresponding to one of the ten different thresholds of reliability ranging from 0.0 to 0.9. The results show that the prediction accuracy of the data-driven methods rose when the threshold increased from 0.0 to 0.5, but the accuracy decreases as the threshold continues to increase after 0.5, that is, from 0.5 to 0.9. The best performance was obtained when the threshold was 0.5. The proposed method was compared with existing methods for absence data generation (i.e. buffer controlled and target space exteriorization). These results show that the similarity-based approach has a better performance than these existing methods for landslide susceptibility mapping using data-driven methods.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Ligang Ma, Shengtian Yang, Qing Gu, Jiadan Li, Xiaodong Yang, Jinjie Wang, Jianli Ding〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Excessive farming has transformed large proportions of Xinjiang's terrestrial surface, which leads to widespread loss and degradation of ecosystems and biodiversity. Mapping croplands at regional scale and in a rapid and less costly approach is becoming increasingly needed. This study explored an integrated approach based on a combined use of multiple remotely sensed data to map croplands in the oasis of northwest China. The Terra MODIS land surface temperature, Enhanced vegetation index, TRMM precipitation and SRTM digital elevation model data products were examined and combined. The Random Forest models were established to estimate fractional croplands at the regional scale. The influences of basin, images and percentage of croplands were all examined on the accuracy of cropland estimation. Moreover, time series analysis of croplands from 2000 to 2017 was conducted across the basin scale. The results are: ① the integrated approach for cropland mapping at regional scale is promising with the explained variances of fifteen trial models ranging from 58%–93% and two basin scale models ranging from 77.21%–86.10%. ② The prediction accuracy of croplands in Tarim Basin was much higher than that in Junggar Basin indicated by explained variances. ③ Prediction errors increase and then decrease with the increase of percentage of croplands. ④ EVI and DEM were identified to be the most important variable in Junggar and Tarim basin. ⑤ During the past 18 years, the area of croplands has been expanding at approximately 641.3km〈sup〉2〈/sup〉/year in Junggar Basin and 271.3 km〈sup〉2〈/sup〉/year in Tarim Basin respectively with no sign of cease. The fastest expansion period and the most dramatic changing area were identified. This study is especially valuable for time series analysis of croplands and its correlation with land degradation in arid region.〈/p〉〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Jun Li, Zhaoli Wang, Chengguang Lai, Zhenxing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Extending series of river streamflow based on tree-ring reconstruction is of scientific and practical importance for understanding hydrological or meteorological change of past. To achieve more accurate reconstructions, the intelligent learning algorithm random forest (RF) was proposed in this study to reconstruct the annual streamflow of the source region of the Yangtze River (SRYR). The method was developed using tree-ring chronologies ranging from 1485 to 2000 (AD) and annual streamflow from 1956 to 2000 (AD). The relationship between streamflow and the main large-scale atmospheric circulation as well as solar activity has also been discussed. The results show that: a) RF model could capture a more realistic characteristic of streamflow and show higher predictive ability for streamflow reconstruction than bagged regression trees (BRT), support vector machine (SVM), and simple linear regression (SLM). b) A period of lower streamflow occurred during the late 16th and mid-18th centuries, and the early 19th and mid-20th centuries experienced higher streamflow; an interesting temporal pattern indicated that the instrumental period was representative of individual highest (1979) and lowest (1989) streamflow years; in addition, a 2–8-year significant periodical oscillation (at 95% confidence level) was observed over most of the reconstructed series, with dominant periods of 2.5- and 4.9-year. c) The variability of streamflow in the study area was strongly associated with Pacific Decadal Oscillation (PDO), El Nino-Southern Oscillation (ENSO) and solar activity. This study provides reference for streamflow reconstruction based on tree-ring data and helps to understand the hydrological variation of past in SRYR.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 183〈/p〉 〈p〉Author(s): Xunming Wang, Junpeng Lou, Diwen Cai, Linlin Jiao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Field investigation, sampling and element analyses were used to analyze the contributions of different surface processes on the heterogeneity of surface soils and the responses of vegetation elements in China's Otindag Desert. The analyzed results show that there are variations in the contributions of different surface processes on the spatial heterogeneity of the surface soils. In this region, the aeolian processes play key roles in the spatial heterogeneity of the surface soils, and the contributions of other processes, such as hydrological processes, dustfall deposition, anthropogenic pollution and underlying rocks, are lower than those of the aeolian processes. In addition, the analyzed results also show that the vegetation elements and communities respond differently to the surface soils. For the 〈em〉A. frigida〈/em〉 community, the soil contents of Co, Mg, Sr, Pr, Nd, Sm, Eu, Tb, Tm, Y, In, La, and Ce may have close relations with community development, while the soil contents of Co, Cu, Ni, Sr, Pr, Nd, Sm, Tb, Y, In, La, Ce, and Bi may affect the development of the 〈em〉S. klemenzii〈/em〉 community in the region. These results show that although surface processes play important roles in the heterogeneity of soil elements, the autogenic adaptability of the community may also result in the heterogeneity of the vegetation elements.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Jeppe Aagaard Kristensen, Susan Helene Boëtius, Mark Abekoe, Theodore W. Awadzi, Henrik Breuning-Madsen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the tropical moist semi-deciduous forests of West Africa, soil catenas with extremely gravel-rich soil horizons at the summits and upper slopes and largely gravel-free profiles at the lower slope are common. Previous investigations have suggested that these gravel layers are the result of macro-invertebrates mining of fine-grained soil material from the subsoil leaving behind the gravel, to build galleries at the surface subsequently exposing it to water erosion transport downslope. We examined the indirect effect of this process on the distribution along a soil 〈em〉catena〈/em〉 of crucial base cations (Ca〈sup〉2+〈/sup〉, Mg〈sup〉2+〈/sup〉, K〈sup〉+〈/sup〉) and plant available phosphorous (P), which is often growth-limiting in these tropical ecosystems. We found that the export of fine-grained soil material at the top of the 〈em〉catena〈/em〉 reduces the soil stocks (to 1 m) of these elements by up to 60%, while the soil fertility downslope did not change significantly. This important long-term (100–1000 yr scale) reduction in soil fertility at the top of slopes resulting from bioturbation and water erosion is overlooked in contemporary literature, which primarily focus on the beneficial impact termites and ants have on ecosystem functioning in more level savannah landscapes. As the type of 〈em〉catena〈/em〉 studied is widespread across tropical environments, this effect is likely ecologically substantial. Future research should aim at understanding such long-term consequences of bioturbation on landscape ecology as well as soil heterogeneity and fertility, so we do not overlook potential negative ecosystem effects.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): D. Moret-Fernández, B. Latorre, M.L. Giner, J. Ramos, C.L. Alados, C. Castellano, M.V. López, J.J. Jimenez, Y. Pueyo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Estimation of soil sorptivity (〈em〉S〈/em〉) and hydraulic conductivity (〈em〉K〈/em〉) is fundamental to model the water infiltration into the soil. This process can be affected by soil water repellency, which is defined as a reduction in soil wettability due to coating of soil particles by hydrophobic substances. Unlike to wettable soils, this phenomenon can generate infiltration curves with double-slope shape: a transient infiltration curve followed by a steady-state section. Because the topsoil final volumetric water content (〈em〉θ〈/em〉〈sub〉〈em〉1〈/em〉〈/sub〉) of the transient phase of the double-slope curve is not a measurable data, in principle, the standard model based on the Haverkamp et al. (1994) model cannot be used to estimate 〈em〉S〈/em〉 and 〈em〉K〈/em〉. This work presents two different approaches based on the Haverkamp et al. (1994) equation, which allow estimating 〈em〉S〈/em〉 and 〈em〉K〈/em〉 from the first phase of a double-slope infiltration curve, when 〈em〉θ〈/em〉〈sub〉〈em〉1〈/em〉〈/sub〉 data are not available. The methods, which are based on the analysis of both short-medium time transient infiltration curve (〈em〉Tr〈/em〉) and the combination of both short-medium transient and steady-state infiltration steps (〈em〉Mx〈/em〉), were applied on 20 soils affected by different degrees of water repellency. The Haverkamp et al. (1994) model was also valid for infiltration curves measured on hydrophobic soils, and the final volumetric water content was not an essential data to estimate 〈em〉K〈/em〉 and 〈em〉S.〈/em〉 Although the steady-state infiltration rate (〈em〉q〈/em〉〈sub〉〈em〉1〈/em〉〈/sub〉) calculated with 〈em〉Mx〈/em〉 was about 26% larger than that estimated with 〈em〉Tr〈/em〉, comparable 〈em〉K〈/em〉 and 〈em〉S〈/em〉 values were obtained with both methods. Overall, a large dispersion on the estimate of 〈em〉θ〈/em〉〈sub〉〈em〉1〈/em〉〈/sub〉 was observed with both methods. The gravimetric time, 〈em〉t〈/em〉〈sub〉〈em〉grav〈/em〉〈/sub〉, estimated in the studied soils was low, 〈500 s. While the 〈em〉Mx〈/em〉 method required simpler numerical calculus, 〈em〉Tr〈/em〉 looked like to be more robust and less subjective.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Xinhui Han, Chengjie Ren, Boyong Li, Shengji Yan, Shuyue Fu, Dexin Gao, Fazhu Zhao, Jian Deng, Gaihe Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil microbial communities are closely associated with aboveground plant communities and soil properties. This study explored the dynamics of soil bacterial communities during the plant growing season and their interaction with soil carbon and nitrogen, physicochemical properties, plant biomass and diversity following afforestation. The study investigated afforested lands containing 〈em〉Robinia pseudoacacia〈/em〉 L (RP) and 〈em〉Caragana korshinskii〈/em〉 Kom (CK), as well as abandoned land (AL) and farmland (FL) in the Loess Hilly Region of northern China. After establishment on former FL for 40 years, the Richness and Shannon's index, above-ground herbaceous biomass (AGB) and below-ground biomass (BGB) in RP and CK increased by 0.5, 0.1, 1.2 and 1.7 times, respectively, compared with AL. Additionally, the soil organic carbon (SOC), total nitrogen (TN), dissolved organic carbon/nitrogen (DOC/N) and microbial biomass carbon/nitrogen (MBC/N) increased by 1.7, 1.9, 0.8 and 2.5 times, respectively, while the soil bacterial abundance and alpha diversity (Shannon index) increased by 4.7% and 2.0% compared with FL. During the growing season, the soil carbon and nitrogen content was higher in August or October than in April or June. Particularly, the AGB, DOC and MBC showed a temporal pattern of normal distribution that was 36.7%, 48.2% and 74.9% higher in August than the rest of the study period. The BGB also increased by 123.5% in October compared with June in all study areas. The soil bacterial abundance in afforested lands was also higher in October, and beta bacterial diversity (Principal coordinates analysis plots: PCoA) was greater in June and August than in April and October. The dominant bacterial taxa, 〈em〉Proteobacteria〈/em〉 and 〈em〉Bacteroidetes〈/em〉, were significantly higher in afforested lands than in FL, and 〈em〉Proteobacteria〈/em〉 increased from April to October, while 〈em〉Actinobacteria〈/em〉 and 〈em〉Acidobacteria〈/em〉 peaked in June or August. These seasonal changes in the soil bacterial community were significantly correlated with carbon and nitrogen levels of soil and plant biomass, especially with DOC and BGB. Additionally, soil variables explained 41.2% of the total variation in bacterial-dominant phyla, while plant biomass only explained 20.2% of it, which indicates that soil properties are more important controlling factors of the bacterial community than plant biomass. In conclusion, soil variables change seasonally, which drives the composition and diversity of the soil bacterial community to exhibit a temporal pattern over the growing season after return of AL to forest.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Jesús Horacio, Efrén Muñoz-Narciso, Alan S. Trenhaile, Augusto Pérez-Alberti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Historical air photographs, LiDAR, and an unmanned aerial vehicle (UAV) were used to record the movement, from 1956 to 2018, of a clay and clast earthflow in a coastal valley in northwestern Spain. Two procedures were employed. The first tracked changes, in a GIS environment, in the location of eight, easily identified objects on the surface of the deposit (large boulders, topographic lobes, and the foundations of an old hut). The second used DEMs of Difference (DoDs) based on Digital Elevation Models from a 2011 LiDAR flight and two UAV flights in 2016 and 2018 obtained by Structure from Motion-Photogrammetry techniques. While the first procedure provided estimates for earthflow movement over a 62-year period, the second produced more precise data for periods of up to 8-years. The first procedure indicated that the mean rate of movement was 0.48 m·yr〈sup〉−1〈/sup〉, increasing from only 0.14 m·yr〈sup〉−1〈/sup〉 from 1956 to 1983 to between 0.50 and 0.83 m·yr〈sup〉−1〈/sup〉 from 1983 to 2018. Despite some temporal and spatial changes in direction, rates of surface movement were quite uniform on the deposit. The increase in earthflow movement after 1983 may be related to an increase in rainfall, although human activities associated with the removal of a wrecked ship from the nearshore may have been a contributing factor. The role of debuttressing due to the wave-induced removal of lateral support from the toe of the deposit is less clear. While there was no clear relationship between wave erosion and rates of movement, coastal retreat may have triggered changes in the direction and sediment flux in the toe of the deposit. This effect could have been tempered by negative feedback, however, whereby coastal erosion and increased flow activity were countered by the protection afforded by the accumulation of large, dislodged boulders on the beach. Because of this feedback, it is difficult to predict the impact of sea level rise and other elements of climate change along this coast.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Yang Wang, Xiao-yan Li, Xiu-chen Wu, Hua-wu Wu, Jing-hui Zhang, Yi-nan Wu, Chuan-yan Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although soil respiration (〈em〉R〈/em〉〈sub〉〈em〉s〈/em〉〈/sub〉), as the largest flux of CO〈sub〉2〈/sub〉 from terrestrial ecosystems to the atmosphere, has been measured and simulated widely, its drivers on different temporal scales in high-altitude regions are not well known. These driving factors were analysed at a site upstream of the Heihe River Basin based on measurements carried out using a field chamber over 3 years during three stages of the 5 cm soil layer: freezing and thawing (FT), completely frozen (CF), and completely thawed (CT). The analysis covered hysteresis with reference to soil respiration, photosynthesis, diurnal changes in soil temperature during CT in the growing season, and the contribution of carbon emissions outside the growing season (winter) to the total annual 〈em〉R〈/em〉〈sub〉〈em〉s〈/em〉〈/sub〉. Results show that 1) the drivers of 〈em〉R〈/em〉〈sub〉〈em〉s〈/em〉〈/sub〉 on the diurnal scale during FT, CF, and CT were totally different: soil temperature (〈em〉T〈/em〉〈sub〉〈em〉5〈/em〉〈/sub〉) and moisture (〈em〉W〈/em〉〈sub〉〈em〉5〈/em〉〈/sub〉) at 5 cm depth for FT; air temperature near soil surface (〈em〉T〈/em〉〈sub〉〈em〉a〈/em〉〈/sub〉) and soil water content at 20 cm depth (〈em〉W〈/em〉〈sub〉〈em〉20〈/em〉〈/sub〉) for CF, and 〈em〉T〈/em〉〈sub〉〈em〉5〈/em〉〈/sub〉 and photosynthetically active radiation (〈em〉PAR〈/em〉) for CT; 2) at the diurnal scale during CT, 〈em〉R〈/em〉〈sub〉〈em〉s〈/em〉〈/sub〉 took 1.48–6.16 h less to reach its peak value than what 〈em〉T〈/em〉〈sub〉〈em〉5〈/em〉〈/sub〉 did, while 0.84–2.81 h more than 〈em〉PAR〈/em〉 did; 3) cumulative 〈em〉R〈/em〉〈sub〉〈em〉s〈/em〉〈/sub〉 in winter was 132.31 g cm〈sup〉−2〈/sup〉, accounted for approximately 16% of the annual carbon efflux from the subalpine meadow. Results suggest that the contribution of winter to the annual total 〈em〉R〈/em〉〈sub〉〈em〉s〈/em〉〈/sub〉 was large and should be considered in assessing carbon budget in high-altitude regions.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219300918-ga1.jpg" width="339" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Veerle Vanacker, Yolanda Ameijeiras-Mariño, Jerome Schoonejans, Jean-Thomas Cornélis, Jean P.G. Minella, Florence Lamouline, Marie-Liesse Vermeire, Benjamin Campforts, Jeremy Robinet, Marijn Van de Broek, Pierre Delmelle, Sophie Opfergelt〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Topography is one of the key factors controlling soil erosion and redistribution of pedogenic material along slope. Land cover change can have an accelerating or retarding impact on topographically-controlled soil erosion rates, depending on the type and intensity of land use and management. In this study, we investigated the combined effect of hillslope gradient and land cover change on soil redistribution and rejuvenation in a subtropical region where Atlantic rain forest was converted to agricultural land. We used a two versus two factorial design, and evaluated the effect of hillslope gradient (steep vs. gentle) and land cover (forest vs. cropland) on the spatial pattern of soil weathering degree along slope. In four soil toposequences, soil weathering indices (Total Reserve in Bases, Chemical Index of Alteration, clay content, iron oxide content) and mineralogical assemblages were used to express genetic and morphological differences among soil profiles. Our data showed that the spatial differentiation in chemical weathering degree along slope is strongly dependent on the hillslope gradient: while the gentle slopes show negligible differences in chemical weathering degree along slope, the steep slopes show clear spatial differences. Besides, there is an interaction effect between hillslope gradient and land cover. Forest conversion to cropland enhances erosion-driven soil redistribution with a marked effect on soil rejuvenation along steep slopes but no clear effect along gentle slopes. The comparative study based on four toposequences highlights that accelerated soil erosion after conversion of forests to cropland has further enhanced lateral soil fluxes and redistribution of topsoil material along steep slopes, and led to soil rejuvenation and exposure of less weathered soil material at the eroding sites.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 179〈/p〉 〈p〉Author(s): Wojciech Piaszczyk, Ewa Błońska, Jarosław Lasota, Martin Lukac〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of this study is to compare the C/N/P stoichiometry of deadwood among four tree species at different stages of decomposition. The way in which the relative concentrations of these elements in the soil are directly impacted by deadwood decomposition is also explored. First, hornbeam, alder, aspen and fir logs in different decomposition stages (III, IV and V) were selected and sampled. Second, the concentration and stoichiometry of carbon, nitrogen and phosphorous were established. Marked differences in C/N/P stoichiometry were observed between deadwood in an advanced decomposition stage and the soil immediately under the log. The average C/N/P ratio of soil under the influence of deadwood was narrower compared to the C/N/P ratio of deadwood. The C/N/P ratio of studied soils was similar to the expected C/N/P ratio of organic soils or humus. The results indicate that stage of decomposition and tree species have an impact on the elemental stoichiometry of the soil. Thus, C/N/P stoichiometry is a useful indicator of the intensity of nutrient flux from deadwood to the soil.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Chu-tian Zhang, Yong Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A better understanding of the spatial pattern of soil organic matter (SOM) is important for scientific soil management. As multisource secondary data become increasingly cheap and readily available, numerous methods have been established to incorporate secondary information; however, these methods exhibit limitations under certain conditions due to their relatively strict requirements on secondary data. In this study, we tried to integrate sampled soil data and secondary data more effectively within the framework of Bayesian maximum entropy (BME). Specifically, multiple linear regression (MLR) and geographically weighted regression (GWR) were run 100 times based on environmental covariates such as terrain indices, vegetation indices and categorical variables obtained from soil maps. Then, the 95% confidence interval was derived from the multiple prediction values at each of the soft data points. For comparison, some conventional techniques, including ordinary kriging (OK), regression kriging (RK) and geographically weighted regression kriging (GWRK), were also applied. The results showed that BME exhibited a prediction accuracy comparable to that of OK and maintained the prediction uncertainty at a low level, while other studied methods (MLR, GWR, RK and GWRK) were all significantly inferior to BME and OK. The proposed methodology in this study represents a promising scenario for the digital soil mapping, especially when the relationships between the target soil attributes and various secondary information are not strong or residuals of trend models show insignificant spatial autocorrelation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Katayoun Haghverdi, Yahya Kooch〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The long-term consequences of changing beech abundance by admixture of valuable broad-leaved species and its effects on nutrient cycling and soil-related processes are not sufficiently investigated. Four different forest types [i.e., beech-hornbeam-maple-alder (〈em〉Fagus orientalis-Carpinus betulus-Acer velutinum-Alnus glutinosa〈/em〉), beech-hornbeam-maple (〈em〉Fagus orientalis-Carpinus betulus-Acer velutinum〈/em〉), beech-hornbeam (〈em〉Fagus orientalis-Carpinus betulus〈/em〉), and pure beech (〈em〉Fagus orientalis〈/em〉)] in northern Iran were evaluated. Litter samples were collected via litter traps, and topsoil samples were taken and analyzed for selected properties. It was found that litter quality and turnover time improved with decreasing beech abundance. Soil pH, total N, nutrient pools (i.e., P, K, Ca, and Mg), C and N stock, fine root biomass, earthworm and nematode activities, respiration, microbial biomass N, C and N mineralization, and dissolved organic N were significantly higher under mixed beech stands. However, water content, C/N ratio, and dissolved organic C were found to be significantly higher under pure beech forest type. Greater amount of soil organic C was found under beech and beech-hornbeam-maple-alder, but the microbial biomass C was not significantly different among different forest types. The stands with higher tree diversity enhanced the level of soil qCO〈sub〉2〈/sub〉 and particulate organic N. A higher value of microbial entropy was recorded under beech-hornbeam stands, whereas soil particulate organic C increased under beech and beech-hornbeam forest types. Based on the result, the abundance of beech influenced nutrient cycling via litter quality and turnover time. This led to an increase in soil fertility through the admixture of broadleaf species into beech forests.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): R. Osman, F. Alaily, A. Sayed, M. Kaupenjohan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soils of two Nile Valleys (White Nile and Blue Nile) and the neighboring Nubian Sandstone plateaus (Qoz) in Central Sudan were investigated. The White and Blue Niles rise from different areas and are different in their water flow velocity, flood amplitude and flooding time. The results of this study show that sediments of both valleys consist of an allochthonous and a parautochthonous component. The allochthonous part of the White Nile and Blue Nile show different texture and mineralogical composition. It consists of smectite-rich clayey material in the White Nile whereas the Blue Nile sediment contains carbonates, is rich on smectite and is silty-clay. The parauthochthone part in both Nile Valleys is sandy and rich on kaolinite. Its origin is predominantly eolian and fluvio-eolian from Nubian Sandstone. Its amount in the first terraces (youngest terraces) is highest and lowest in the second Terraces. This point out, that the youngest terraces as well as the third terrace on the Blue Nile were developed in a time when the surrounding area was covered with a loose vegetation cover (ergo-dry climate) and the second terraces were developed in a period with a dense vegetation cover (ergo wet climate).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Kunyong Yu, Xiong Yao, Yangbo Deng, Zhuangjie Lai, Lingchen Lin, Jian Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is of great importance to assess the effect of stand age on soil respiration (SR) to understand the potential carbon sequestration capacity of afforestation. In this study, we investigated the changes in SR and microclimate variables in a chronosequence of four different aged stands (8-, 17-, 27-, and 36-year-old) in a 〈em〉Pinus massoniana〈/em〉 plantation in the soil erosion area of southern China. SR was found to have obvious seasonal dynamics among the four aged stands, and the highest and lowest value in summer and winter, respectively. We also found that SR increased with increasing stand age, and the mean SRs for the 8-, 17-, 27-, and 36-year-old stands were 1.45, 1.83, 2.03, and 2.32 μmol CO〈sub〉2〈/sub〉 m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉, respectively. Furthermore, all stands showed that SR increased exponentially with increasing soil temperature and that the temperature sensitivity of SR (Q〈sub〉10〈/sub〉) was 2.08, 2.09, 2.23, and 2.19 for 8-, 17-, 27-, and 36-year-old stands, respectively. Moreover, the Q〈sub〉10〈/sub〉 values for the 27- and 36-year-old stands were significantly higher than those of the other two stands (〈em〉p〈/em〉 〈 0.05). Stepwise multiple regression analysis indicated that soil temperature had a greater effect on SR than soil organic carbon. This study provides insights for estimating SR in 〈em〉P. massoniana〈/em〉 plantations in the eroded area of southern China and highlights the need to consider the effect of stand age and seasonal patterns when predicting the carbon budget under different future climate change scenarios.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Ondřej Bábek, Ondřej Kielar, Zuzana Lenďáková, Kateřina Mandlíková, Jan Sedláček, Jitka Tolaszová〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Interpretation of catchment pollution history from sediment cores is a common approach for dam reservoirs, but relatively little is known about the spatial distribution of pollutants in the lithologically diverse depositional subsystems. We studied the depositional system of a hundred-year-old valley-type reservoir of the Les Království Dam built in 1919 on the upper reaches of the Elbe River, Czechia. Based on the analysis of pre-dam river valley morphology using historical topography maps with 1 m vertical resolution, 30 ground-penetrating radar sections on the lake and 〈sup〉137〈/sup〉Cs dating of four cores, we described a deltaic sediment body with maximum thickness of ~11 m, accumulation rates ranging from 3.6 to 9.7 cm/yr, and an annual loss in reservoir capacity of 0.8%. The sediment body has a distinct delta shape in the longitudinal section, with a delta platform dissected by a channel (topsets) and delta slope (foresets) and a ponded basin (bottomsets) located near the dam. The upstream sections of the channels are prone to erosion and sediment redistribution into downstream parts of the reservoir, as indicated by ground-penetrating radar sections and distribution of 〈sup〉137〈/sup〉Cs in younger sediment strata.〈/p〉 〈p〉We retrieved four cores 1.0 to 1.6 m long from different parts of the delta and analysed the sediment grain size using laser granulometry, geochemical composition (X-ray fluorescence, ICP-MS lithogeochemistry, total organic carbon (TOC)) and concentrations of polycyclic aromatic hydrocarbons (PAH). The grain size variation between the delta platform (sandy silts and silty sands) and prodelta (clayey silts) sediments strongly controls the concentrations of lithogenic elements (Al, Fe, K and Ti) but it has a relatively little effect on distribution of toxic metals (Zn, Cu, Pb) and TOC concentrations. The toxic metals show strong affinity to TOC and PAH show a distinct sawtooth vertical distribution suggesting that they were deposited from depositional events during hyperpycnal flows induced by river floods. This study shows that a hyperpycnal delta may serve as a good predicable model for toxic metal- and organic pollutant distribution in dam reservoirs. The role of hyperpycnal flows should not be overlooked in contamination studies of dam reservoirs.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Hannah Lehnhart-Barnett, Susan Waldron〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fluvial dissolved and particulate organic carbon concentrations, [DOC] and [POC], were measured weekly in two contrasting catchments in east Iceland in June and July 2016. Sampling was carried out at ten sites in each catchment, including the outlets. [DOC] ranged from 2.1 to 6.6 mg L〈sup〉−〈/sup〉〈sup〉1〈/sup〉, and [POC] from 0.4 to 3.1 mg L〈sup〉−〈/sup〉〈sup〉1〈/sup〉. Mean TOC fluxes over the sampling period amounted to 0.46 μg m〈sup〉−〈/sup〉〈sup〉2〈/sup〉 s〈sup〉−〈/sup〉〈sup〉1〈/sup〉 from the West catchment and 0.42 μg m〈sup〉−〈/sup〉〈sup〉2〈/sup〉 s〈sup〉−〈/sup〉〈sup〉1〈/sup〉 from the East catchment. Concentration and flux data were used to analyse the relationship between organic carbon budgets and different land cover: heathland, wetland, sparse vegetation and dense Nootka lupin (〈em〉Lupinus nootkatensis〈/em〉). Wetland area, associated with C-rich Histic Andosols, was found to have a significant positive influence on in-stream organic carbon concentrations and fluxes, and the opposite was found with sparsely vegetated areas, likely due to limited soil development. Areas with dense lupin cover were associated with relatively-low organic carbon fluxes in the East catchment, possibly because lupin stabilises its substrate, reducing mobilisation of DOC and POC. In the West catchment this influence was not clear, but this is likely due to the co-location of wetland, causing increased C exports.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Chao Guo, Zhongwu Jin, Leicheng Guo, Jinyou Lu, Shi Ren, Yinjun Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Climate change and anthropogenic activities such as dam construction alter basin-scale hydrological regime of a river. The upper Changjiang River (uCR) stands out as one of the most heavily dammed rivers in the world after the construction of the Three Gorges Dam (TGD) and other large dams in its mainstem. Quantification of the cumulative dam impact is prerequisite for better river management. In this work, we provide a rigorous appraisal of the changes in streamflow, sediment load, and sediment composition at multiple time scales throughout the uCR based on data in 1950–2017. We observed that a decreasing trend in annual streamflow has emerged since 2015 at Yichang, the outlet of the uCR basin, although the changes were statistically insignificant for the first 65 years. The annual sediment load has decreased progressively and substantially, e.g., by 97% in 2010s compared to 1950s at Yichang. The Three Gorges Dam and the new large dams in the upstream mainstem accelerated the sediment load reduction in 2003 and 2014, respectively. As a result, the suspended sediment became finer, with a decrease in mean diameter from 17 μm in the 1960s to 8 μm in the 2010s at Yichang. We established a reservoir storage capacity index, which is the ratio of the total reservoir storage capacity to annual streamflow, and identified a threshold of 4% larger than which the cumulative dam impact will induce profound sediment load reduction. We concluded that climate change and anthropogenic activities, in particular the large dams in the mainstem, have transformed the uCR system from a turbulent and muddy river to a placid one, which can affect fluvial processes as well as aquatic ecosystems by altering sediment and nutrient concentrations and ratios. These hydro-morphological changes merit the urgent attention of concerned authorities.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Gianmarco Mugnai, Federico Rossi, Sonia Chamizo, Alessandra Adessi, Roberto De Philippis〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Cyanobacteria are widespread prokaryotic organisms that represent feasible biotechnological tools to set up valid approaches to counteract desertification. Their peculiar physiological traits, and their resilience to abiotic stresses, allow their application on abiotically constrained soils to trigger their stabilization. A successful cyanobacteria inoculation results in the formation of cyanobacterial biocrusts, complex microbial communities characterized by tangled filament meshes imbued in a matrix of self-secreted extracellular polysaccharides (EPS) that keep loose sediments and aggregates firmly in place. However, the capability to form stable cyanobacterial biocrusts is not common to all the species, and a mix of factors can hamper the process, notably inoculum amount, and substrate characteristics.〈/p〉 〈p〉The aim of this work was to assess the influence of inoculum quantity and substrate granulometry on the physical stability of cyanobacterial biocrusts induced by inoculating the strain 〈em〉Leptolyngbya ohadii〈/em〉 in a microcosm experiment, under laboratory conditions. After applying three different initial inoculum amounts on two different sand granulometries (medium and coarse sand), we assayed aggregate stability, physical stability and surface hydrophobicity on the resulting biocrusts during a 30-day incubation. Also, the features and the role of the EPS synthesized by L. 〈em〉ohadii〈/em〉 were studied following their isolation, characterization, and direct application on the sand. The two EPS fractions produced by the strain, one more soluble and easily released in the surrounding medium (released polysaccharides, RPS) and one solidly attached to the filaments (glycocalyx EPS, G-EPS), were separately tested.〈/p〉 〈p〉Cyanobacterial biocrusts visibly formed in all the microcosms after 15 days. However, we observed a strong effect of sand granulometry in affecting aggregate stability and tensile strength, both of which appeared weaker on coarse sand. A higher amount of initial inoculum was necessary to produce stable biocrusts on coarse sand compared to medium sand. Also, we observed how the inoculation of EPS alone did not sort most of the significant effects that we detected by inoculating the whole culture, pointing at the importance of the action of the cyanobacterial filaments in soil conglomeration. However, a significant increase in physical stability was achieved by inoculating G-EPS on medium sand, suggesting the involvement of this fraction in biocrusts structuration.〈/p〉 〈p〉This work analyzes for the first time the effects of the variable grain size and inoculum amount in the achievement of physically stable biocrusts by cyanobacteria inoculation. The results that we obtained are useful in improving and optimizing the process of biomass preparation and dispersion for future indoor and outdoor studies.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Kritika Malhotra, Jasmeet Lamba, Stephanie Shepherd〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Excessive delivery of fine-grained sediment and sediment-bound nutrients to surface waters results in water quality impairment. Information on the relative contribution of different sources contributing sediment to river systems is a prerequisite to target management practices. The overall goal of this study was to determine the sources of stream bed sediment at a subwatershed scale using sediment fingerprinting approach in an urbanized, 31 km〈sup〉2〈/sup〉 Moore's Mill Creek watershed in Southern Piedmont region in Alabama, USA. The relative source contribution from construction sites and stream banks was quantified for two different particle size fractions, 63–212 μm (fine sand) and 〈63 μm (silt and clay). Results of this study showed that both construction sites and stream banks were important sources of stream bed sediment. The stream bed sediment in the upstream reaches originated largely from channel bank sources, and in the lower reach (watershed outlet), construction sites were the dominant sources of stream bed sediment. The results of this study showed that the relative source contribution from different sources is dependent on the particle size of the sediment, time and location of sampling within a watershed, riparian buffers, and areas of construction activities in proximity to the sampling sites. Conservation practices in this watershed should be targeted to stream banks or construction sites depending upon the dominant source of stream bed sediment within a subwatershed. Overall, this study underscores the importance of considering the spatial and temporal variability of sediment sources as a function of sediment particle size for targeted implementation of best management practices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Diane Saint-Laurent, Lisane Arsenault-Boucher〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soils and tree species are studied in mixed temperate forests along the Coaticook River (Southern Québec, Canada) to examine the effect of frequent floods on soil properties and vegetation. The soils and tree stands are located in the flood zones (FZ) and no-flood zones (NFZ) in 49 quadrats. Different statistical analyses were carried out on soils and tree data, including ANOVA, Kruskal-Wallis, Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA) ordinations. The variables used for soil property analysis were pH, total organic carbon, total nitrogen, C/N ratio, total sulfur, Fe + Al, texture, bulk density, soil moisture, and soil biomass (litter), while the vegetation variables consisted of the number of tree species, their density, and the diameter and measurement of the basal area. The soil property analyses show significant differences between alluvial and non-alluvial soils, including organic carbon, nitrogen, pH, Fe + Al, soil moisture, texture, and plant litter thickness (cm). The PCA ordination realized on soil variables shows two distinct axes, including a first axis (PC1) grouping TOC, TN, TS, soil moisture and pH variables, and accounting for 35% of the total variation, and a second axis (PC2) that includes textural variables (clay and silt) and representing 21% of the total variability. The species richness and diversity analyses did not show statistical differences for the tree species between the two zones that were analyzed (FZ and NFZ), although some tree species are associated with the specific edaphic conditions. The results of the CCA ordination conducted on soil and vegetation data revealed that the tree communities have a significant response to soil variables and flood frequency. All the variables that were studied account for 40% of the variation in species composition based on soil properties. This study shows that successive floods affect soil properties, including depletion of soil organic carbon and nitrogen, and that floods and soil conditions can have a direct effect on the distribution of certain tree species.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Chuanhua Li, Hao Sun, Xiaodong Wu, Haiyan Han〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Biome-BGC (biome biogeochemical cycles) model is widely used for modeling the net primary productivity (NPP) of ecosystems. However, this model ignores soil water changes during the freeze-thaw process in permafrost regions, which may lead to considerable errors in the NPP estimations. In this study, we proposed a numerical simulation method for improving soil water during the freeze-thaw process based on the field observation data of soil water and temperature. This approach does not require new parameters and has no impact on other modules. The improvement of soil water content during the freeze-thaw process was then incorporated in the Biome-BGC model for NPP in an alpine meadow in the central Qinghai-Tibetan Plateau (QTP). The results indicated that this method effectively reduced the RMSEs (root mean square errors) of the simulated soil moisture, leaf area index, and NPP, indicating that this approach performs well in the Biome-BGC model. This study suggested that the improvement of soil water content during the freeze-thaw process is also applicable to other models and, thus, could be a useful method to reduce the uncertainty of NPP estimations in permafrost regions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 184〈/p〉 〈p〉Author(s): Ali Sungur, Alaaddin Vural, Ali Gundogdu, Mustafa Soylak〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the possible impacts of an antimonite mineralization area on agricultural lands with regard to heavy metal concentrations were examined. In this scope, surface soil samples (0–20 cm) were taken from a total of 27 locations including eleven from the Avliyana antimonite mineralization area (Torul, Gümüşhane-NW Turkey) and its surroundings, eleven from agricultural areas and five from the control area. Wet digestion method was used with 〈em〉aqua regia〈/em〉 procedure for determining the total heavy metal (Cd, Cr, Cu, Ni, Pb, Zn) concentrations of the soil samples. The geochemical fractions of heavy metals in soil samples were determined by way of a sequential extraction procedure. The total heavy metal contents of the soils were determined as: Ni 〉 Cr 〉 Zn 〉 Cu 〉 Pb 〉 Cd for control soils, Cr 〉 Ni 〉 Zn 〉 Cu 〉 Pb 〉 Cd for agricultural soils and Zn 〉 Cu 〉 Ni 〉 Cr 〉 Pb 〉 Cd for mining area soils. It was determined that especially the values of Zn (57.6 ± 6.2 μg/g) and Cu (52.4 ± 5.8 μg/g) were high at the mineralization area due to hydrothermal alterations that are effective in the formation of mineralization. It was put forth as a result of sequential extraction that the heavy metals examined excluding Pb were observed dominantly in the residual fraction for all data set. On the other hand, it was determined that the non-residual mobile fractions reached from 11% Cr to 78% Pb in control soils, from 20% Cd to 88% Pb in agricultural soils and from 24% Cd to 87% Pb in mineralization area soils. Contamination signals due to mineralization area were monitored by way of the metal content in mobile fractions. Even though the metal concentrations determined in short term are not alarming for agricultural production, signals were observed especially for Cd, Pb, Cu, Ni and Zn elements to be more mobile in mineralization area soils in the long term due to the impact of environmental factors thereby being carried over to and accumulating in agricultural soils. In conclusion, while it is expected that the metal inputs due to mineralization areas may increase in the future, it is suggested to include plant analyses in future studies for determining the impact of the amount of bioavailable metal.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 188〈/p〉 〈p〉Author(s): S. Mirzaee, S. Ghorbani-Dashtaki, R. Kerry〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil erosion prediction and conservation planning require detailed soil data under different environmental conditions. When such data are needed at the field scale, aspatial and spatial models could be used to predict soil erosion processes. This study was conducted to develop spatial models including geostatistical models (i.e. ordinary kriging (OK) and cokriging (CK)) and hybrid geostatistical models (i.e. multiple linear regression-kriging (MLRK) and artificial neural network-kriging (ANNK)) for estimating WEPP baseline soil sensitivity to erosion parameters for calcareous agricultural soils in northwest Iran. Inter-rill and rill erosion simulation experiments were carried out at 100 locations at the field scale with 3 replications. At each location, the soil properties (organic matter, calcium carbonate equivalent, sand, silt, clay, base infiltration rate) were measured and auxiliary data obtained from attributes derived from digital elevation models (elevation, slope, stream power index, wetness index and sediment transport index) and remote sensing data (three visible bands, NIR, SWIR (5 and 7 bands), NDVI indices). The MLR and ANN models were used to estimate baseline inter-rill soil sensitivity to erosion (K〈em〉〈sub〉ib〈/sub〉〈/em〉) and rill soil sensitivity to erosion (K〈em〉〈sub〉rb〈/sub〉〈/em〉 and τ〈em〉〈sub〉cb〈/sub〉〈/em〉) using two types of input data. For the first type of prediction models (type I), the measured soil properties and auxiliary data were used, whereas for the second type of models (type II), principal components (PCs) based on the soil and auxiliary data were used. In comparison to the models that were developed here, the WEPP inter-rill and rill soil sensitivity to erosion models showed a relatively poor performance. The ANN models developed here predicted K〈em〉〈sub〉ib〈/sub〉〈/em〉, K〈em〉〈sub〉rb〈/sub〉〈/em〉 and τ〈em〉〈sub〉cb〈/sub〉〈/em〉 parameters better than the MLR models using both types of data (type I and II). Moreover, the results indicated that the ANNK model was the most appropriate spatial or hybrid model for predicting soil sensitivity to erosion parameters.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): A. Brook, N. Shtober-Zisu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Inland notches are elongated C-shape indentations carved into hard, dense carbonate rocks of the Mediterranean climate zone. In recent years these unique features became of particular interest as geoindicators of denudation and slope erosion processes. The study goals are to learn the processes acting upon the notches cavity by (1) examining the micromorphology of the backwall, (2) identifying and classifying zones of erosion, (3) learning the surface flow pattern and, (4) proposing an erosion mechanism induced by exfoliation. To this end, a machine learning algorithm was designed, using the microstructure, texture, streamlines formation and potential focal flow. The workflow uses data from terrestrial laser scanning, applies high-resolution textural and curvature analyses and trains an artificial neural network to the different segments of the notch. The reconstructed surface model shows division into three distinct belts within the cavity surface: (1) The spalled belt [SB]; (2) The transition zone belt [TZ] and (3) The deposition belt [DB]. Each belt owes its distinct microtopography, implying on different geomorphic processes. The newly developed methodology improves the recognition of streamline networks along the cavity backwall, which mimic alluvial networks. The organization of the reconstructed micro channels is similar to drainage basin systems, where, first order channels developed upstream converge into larger ones and diverge as distributaries as the gradient decreases, depositing tufa along the notches base.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Cheng Hong, Liu Chenchen, Zou Xueyong, Li Huiru, Kang Liqiang, Liu Bo, Li Jifeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vegetation is regarded as the most effective measure for soil erosion control and sand control projects, which plays an important role in controlling soil wind erosion and sand disasters in arid and semiarid regions. Most of the existing models for soil wind erosion rate prediction are based on empirical results that consider factors such as vegetation coverage and wind speed but have rarely investigated the wind erosion rate from the shear strength perspective, which is also an important reason why it is difficult for existing wind erosion models to be popularized. In fact, the presence of vegetation alters the distribution of the near-surface airflow field and thus profoundly changes the magnitude and spatial distribution of shear stress generated by airflow on soil particles. According to existing theories, it is very difficult to describe these processes. Although the shear stress on a vegetation-covered soil surface may be measured using existing observation techniques, difficulties in technology make it impractical for conducting at a large scale. Consequently, research that combines soil wind erosion and the shear strength of vegetation-covered soil surfaces has rarely been reported. Therefore, the prediction of discrete wind erosion rates considering the uneven spatial distribution of the airflow field has gradually become a new trend in the study of the wind erosion of vegetation-covered soil surfaces. In this study, the model for the airflow field of a single plant and the conversion model for the airflow field from a single plant to multiple plants were examined, based on which parameters, such as vegetation characteristics and plant density in wind tunnel tests, were combined to simulate the spatial distribution of the airflow field over vegetation cover surface under four different vegetation coverages. A method for calculating the effective shear strength of the vegetation-covered soil surface was proposed, and the effective shear strength of the surface with different vegetation covers was determined. The effective shear strength of the vegetation-covered soil surface was found to increase with increasing wind speed, decrease with increasing vegetation coverage, and decrease with increasing particle size. On this basis, the relationship between the wind erosion rate 〈em〉q〈/em〉 and the effective shear strength 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mover〉〈msub〉〈mi〉τ〈/mi〉〈mrow〉〈mi mathvariant="italic"〉eff〈/mi〉〈/mrow〉〈/msub〉〈mo〉¯〈/mo〉〈/mover〉〈/mrow〉〈/math〉 of the vegetation-covered soil surface was quantitatively established as 〈em〉q〈/em〉 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈mo linebreak="goodbreak" linebreakstyle="after"〉=〈/mo〉〈mi〉k〈/mi〉〈msqrt〉〈mrow〉〈mi〉d〈/mi〉〈mo stretchy="false"〉/〈/mo〉〈mi〉g〈/mi〉〈/mrow〉〈/msqrt〉〈mo〉·〈/mo〉〈mover〉〈msub〉〈mi〉τ〈/mi〉〈mrow〉〈mi mathvariant="italic"〉eff〈/mi〉〈/mrow〉〈/msub〉〈mo〉¯〈/mo〉〈/mover〉〈/mrow〉〈/math〉, where 〈em〉k〈/em〉 = 114.02. Findings of this study help to explain the wind erosion dynamics of a vegetation-covered soil surface and can also provide a solid foundation for constructing a wind erosion prediction model based on the theory of dynamics.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 188〈/p〉 〈p〉Author(s): Duminda N. Vidana Gamage, Asim Biswas, Ian B. Strachan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Time stability of soil water storage (SWS) is the similarity of spatial patterns of soil water storage over time and is scale and location dependent due to multivariate effects of controlling factors. However, our understanding of scale and location dependency of the time stability of SWS and its seasonally dependent controls in cropped fields is inadequate. This study examined the scale and location dependent time stability of SWS at multiple depths, over different seasons in a cropped field in western Quebec, Canada. Soil water content was measured at 0.05, 0.10 and 0.20 m depths along six transects (128 locations per transect) using the actively heated fiber optic (AHFO) technique. Wavelet coherency analysis was used to examine the scale and location dependent time stability of SWS over different seasons. Results showed strong intra-seasonal time stability across all scales, locations and depths during the dry period in the summer due to a dominant control of evapotranspiration (ET). The weak inter-seasonal time stability of SWS showed the change in the dominant processes controlling the spatial patterns of SWS in different seasons. While the intra-seasonal time stability was also strong during the wet period of autumn, correlations were not significant across all scales, locations and depths, likely due to the dominant effects of smaller to medium scale processes. The results of the study clearly showed that the dominant hydrological processes controlling the time stability of SWS at different depths during a dry period in summer were different than that of a wet period in autumn. The change in the dominant hydrological processes affected the spatial scales and the locations of the similarity of the spatial patterns of SWS in the field. Therefore, the analysis outcome can be used to identify the change in the sampling domain as controlled by the hydrological processes operating at different scales and locations delivering the maximum information with minimum sampling effort.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Xiaohan Wang, Jianghua Yang, Xuefeng Xie, Xinjian Chen, Lijie Pu, Xiaowei Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Large area of tidal flats in Chinese coast has been reclaimed to support agriculture and urban development because of rapid population and economic growth. Knowledge of soil development mechanisms is essential for efficient management of land resources in coastal zone. So far, most studies have focused on consequences of soil physico-chemical properties on soil quality evolution after tideland reclamation for cultivation. However, a large part of soil bioprocess drives many soil processes and the effect of organism composition on the performance of soil development remains unclear. In this study, temporal dynamics of microbial communities were investigated by DNA metabarcoding to delineate the patterns and drivers of soil microbial succession along a chronosequence since reclamation from tidal flat in the Yangtze River Delta of China. Soil physicochemical properties and soil microbial structure shifted significantly, indicating the development of soil fertility. Both soil bacterial and eukaryotic diversities significantly increased after about 60 years of agricultural reclamation. Succession of bacterial structure was linked with significant decrease in the relative abundance of Proteobacteria and increase in the relative abundance of Acidobacteria. Succession of eukaryote structure exhibited significant decrease in the relative abundance of Metazoa and Ochrophyta and increase in the relative abundance of Fungi. Further analysis indicated that temporal and environmental filters act together to structure soil microbial communities across long-term cultivation. An orderly growth of soil microbial community and diversity with respect to soil fertility development has been verified. The succession of soil microbial community and diversity towards higher soil quality after the tidal flat reclamation, which was mainly correlated with soil physicochemical changes with time.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 188〈/p〉 〈p〉Author(s): Zheng-Rong Kan, Shou-Tian Ma, Qiu-Yue Liu, Bing-Yang Liu, Ahmad Latif Virk, Jian-Ying Qi, Xin Zhao, Ratan Lal, Hai-Lin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Understanding the process of soil organic carbon (SOC) sequestration and mineralization in aggregates is pertinent to mitigate climate change and minimize risks of soil degradation. Thus, soil samples were obtained after a 10-year field experiment to identify the influences of tillage on aggregate-associated SOC sequestration and mineralization in the North China Plain (NCP). Four tillage practices investigated were as follows: no-till with straw retention (NTS, conservation tillage), rotary tillage with straw incorporation (RTS), conventional tillage with straw incorporation (CTS), and conventional tillage with straw removal (CT). Significantly negative correlations were observed between SOC concentration and potentially mineralized carbon in aggregates under different treatments for the 0–10 cm soil layer. The large macro-aggregates (〉2 mm) with the highest proportion of size distribution represented the major pool of SOC stock (47.3–51.2%) and mineralization amount (38.2–43.6%) in the 0–30 cm layer, followed by that in the small macro-aggregates (0.25–2 mm), regardless of tillage practices. However, the mineralization quotient (mineralization per unit SOC concentration) of macro-aggregates (〉0.25 mm) was lower than that for the other size classes. The NTS enhanced the macro-aggregate formation in the 0–20 cm layer and associated SOC concentration in the 0–10 cm layer. Furthermore, NTS decreased total potential mineralization in the 0–30 cm layer compared with the other tillage practices, attributed to decrease in the large macro-aggregates (30.0–51.4%) with low particulate organic carbon (POC) concentration. The NTS with low straw inputs had higher incremental efficiency with straw incorporation than that in the RTS and CTS by 45.0% and 13.5%, respectively (〈em〉P〈/em〉 〈 0.05). Overall, the higher proportion of macro-aggregates recorded under NTS decreased carbon mineralization, and consequently, increased incremental efficiency with straw incorporation, and improved SOC sequestration in the surface soil layer in the NCP.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Havalend E. Steinmuller, Michael P. Hayes, Nia R. Hurst, Yadav Sapkota, Robert L. Cook, John R. White, Zuo Xue, Lisa G. Chambers〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Coastal wetlands in Louisiana experience high rates of edge erosion due to combined eustatic sea level rise and coastal subsidence. This study sought to (1) evaluate site-specific spatial and temporal patterns in marsh edge erosion rates within Barataria Bay, LA, (2) develop an understanding of the physical and chemical properties of eroding soils through biogeochemical and spectroscopic characterization, and (3) evaluate interactions between erosion, saltwater incursion, and soil properties through a comparison of sites with different erosion rates and varying distances from the eroding edge. Replicate soil cores were collected at three distances inland (1 m, 3 m, 5 m) at three different sites (west, south, and north) to a depth of 1 m. Erosion rates were measured at each site, and soils were sectioned into 10 cm intervals for a total of 270 soil and porewater samples. Each soil sample was subjected to soil physicochemical analysis (bulk density, moisture content, organic matter content, and total carbon (C), nitrogen (N), and phosphorus (P)) as well as assessments of biogeochemical cycling (production of CO〈sub〉2〈/sub〉, mineralization of N and P, and extractable nutrient concentrations). Porewater samples were analyzed to elucidate spectroscopic and fluorometric indicators of carbon quality (aromaticity, humification, lignin proportion, and C source). Erosion rates at the west, north, and south sites were 3.36 ± 0.4, 1.34 ± 0.2, and 0.58 ± 0.03 m yr〈sup〉−1〈/sup〉, respectively. Neither erosional magnitude nor saltwater incursion was found to be significant predictors of any measured spectroscopic or biogeochemical parameters, though depth was a significant control on 18 of the measured 20 parameters. The top 30 cm were more biologically active (as indicated by greater mineralization of C, N and P) and were characterized by lower molecular weight porewater DOM with less aromaticity. Degree of humification and aromaticity of porewater DOM increased with both depth and distance inland. Concentrations of bioavailable N and P at 1 m depth were at least 5 times greater than surface concentrations, representing a pool of nutrients that could be exported into the coastal ocean with ongoing erosion. This study is the first to couple spectroscopic and biogeochemical measurements for the purpose of assessing soil and porewater physicochemistry within wetland soils and illustrates an as-yet unaccounted for potential for the export of labile C, N, and P into the coastal ocean.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Jing-Bo Zhao, Yan-Dong Ma, Jun-Ji Cao, Yu-Fen Hao, Tian-Jie Shao, Xiu-Ming Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The relationship between Holocene climate change and the evolution of civilizations, both in China and elsewhere, is of increasing research interest. Here we present the results of a study of the particle size, CaCO〈sub〉3〈/sub〉 content, magnetic susceptibility, and soil microstructure of the Holocene paleosol and loess sequence at the sites of Luochuan and Lintong in the southern Chinese Loess Plateau. The results reveal that the paleosol in the late stage of the mid-Holocene is less developed than that in the early stage, and that the corresponding average annual precipitation was at least 100 mm higher than today, due to the enhancement of the summer monsoon. Climatic deterioration occurred in the middle stage of the mid-Holocene, during 6000–5000 yr BP, which was the coldest and driest stage. Four stages of monsoon change occurred in the study area during the Holocene: at 8500, 6000, 5000, and 3100 yr BP. They enable the following climatic subdivision of this interval: three cold and dry periods with enhanced winter monsoon and dust storm activity, and two warm humid periods with a strong summer monsoon and weak dust storm activity. The transformation of the monsoon climate since 3100 yr BP indicates that the modern interglacial period, compared with the last interglacial, is not typical and possesses some of the characteristics of cold and dry climates. The observed pattern of climate change since the mid-Holocene has substantially affected the development of civilization in the region. This is manifested by the frequent migration of ancient capitals caused by the onset of a cold and dry climate: the location of capitals shifted from high altitudes in the Loess Plateau to loess tableland areas on the lower altitude plains, including to the first terrace in the low-altitude plain and then to the moderately-high second terrace of the Wei River. Our results contribute to an improved understanding of the climatic drivers of human civilization in China and provide a basis for predicting future environmental changes in the region.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Christos A. Karavitis, Demetrios E. Tsesmelis, Panagiotis D. Oikonomou, Orestis Kairis, Constantinos Kosmas, Vassilia Fassouli, Coen Ritsema, Rudi Hessel, Victor Jetten, Nikolaos Moustakas, Branislav Todorovic, Nikolaos A. Skondras, Constantina G. Vasilakou, Stavros Alexandris, Elpida Kolokytha, Demetrios V. Stamatakos, Ruzica Stricevic, Emmanuel Chatzigeorgiadis, Jane Brandt, Nicky Geeson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Desertification constantly and diachronically manifested itself as one of the most critical environmental issues to be confronted and mitigated by society. This work presents the development of a land desertification risk Expert System (ES) for assessing the application of different land management practices by utilizing indicators through a desertification risk index (DRI). The DRI was developed by a desertification risk assessment framework generated in seventeen study sites worldwide. This assessment was performed through a methodological process incorporating indicators suited to a plethora of physical, social and economic characteristics. Then, the Desertification Risk Assessment Support Tool (DRAST) was created using the indicators’ methodology in an effort to efficiently handle complexity and variability in soil and water resources management. To demonstrate DRAST’s applicability, an independent data base of indicators was used, and the tool was employed in all the seventeen study sites. Five indicative sites, experiencing different desertification processes, are selected as key representatives of the methodological process implementation. Overall, the assessment depicted that DRAST performs appropriately in demarcating existing desertification risk as well as in portraying how the desertification risk changes after the application of pertinent mitigation actions. Thus, the current approach may lead towards a standardized procedure, which is using the advantages of information technology to assess the effectiveness of various land management practices and facilitate stakeholders and decision-makers to produce and implement timely and appropriate responses to combat desertification.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Davoud Davoudi Moghaddam, Omid Rahmati, Mahdi Panahi, John Tiefenbacher, Hamid Darabi, Ali Haghizadeh, Ali Torabi Haghighi, Omid Asadi Nalivan, Dieu Tien Bui〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Machine learning models have attracted much research attention for groundwater potential mapping. However, the accuracy of models for groundwater potential mapping is significantly influenced by sample size and this is still a challenge. This study evaluates the influence of sample size on the accuracy of different individual and hybrid models, adaptive neuro-fuzzy inference system (ANFIS), ANFIS-imperial competitive algorithm (ANFIS-ICA), alternating decision tree (ADT), and random forest (RF) to model groundwater potential, considering the number of springs from 177 to 714. A well-documented inventory of springs, as a natural representative of groundwater potential, was used to designate four sample data sets: 100% (D〈sub〉1〈/sub〉), 75% (D〈sub〉2〈/sub〉), 50% (D〈sub〉3〈/sub〉), and 25% (D〈sub〉4〈/sub〉) of the entire springs inventory. Each data set was randomly split into two groups of 30% (for training) and 70% (for validation). Fifteen diverse geo-environmental factors were employed as independent variables. The area under the operating receiver characteristic curve (AUROC) and the true skill statistic (TSS) as two cutoff-independent and cutoff-dependent performance metrics were used to assess the performance of models. Results showed that the sample size influenced the performance of four machine learning algorithms, but RF had a lower sensitivity to the reduction of sample size. In addition, validation results revealed that RF (AUROC = 90.74–96.32%, TSS = 0.79–0.85) had the best performance based on all four sample data sets, followed by ANFIS-ICA (AUROC = 81.23–91.55%, TSS = 0.74–0.81), ADT (AUROC = 79.29–88.46%, TSS = 0.59–0.74), and ANFIS (AUROC = 73.11–88.43%, TSS = 0.59–0.74). Further, the relative slope position, lithology, and distance from faults were the main spring-affecting factors contributing to groundwater potential modelling. This study can provide useful guidelines and a valuable reference for selecting machine learning models when a complete spring inventory in a watershed is unavailable.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): M. Ließ〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In environmental research, there is an extensive knowledge of the underlying processes that cause a distinct spatial landscape pattern of system properties. Statistical sampling theory deals with how a dataset must be constructed that allows for the transferability of the insights from the collected data to the system. Stratified and balanced sampling schemes applied for environmental survey, seek to reduce the necessary amount of data to capture the spatial heterogeneity of a landscape. The particular design’s specification depends on the field of application. Against this background, the author strives to draw the attention to the conceptual shortcomings of conditioned Latin hypercube sampling (cLHS) in the context of soil survey and digital soil mapping. Furthermore, a new sampling design is presented which (1) combines the advantages of both, stratified and balanced designs, (2) shows consistency in the application of pedogenetic theory, and (3) which can be obtained by some simple modifications to the computer code of cLHS. Overall, this manuscript shall promote a vivid discussion in the Pedometrics community concerning the consideration of scientific domain knowledge in statistical sampling theory.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S034181621930565X-ga1.jpg" width="289" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 188〈/p〉 〈p〉Author(s): Yanjun Guan, Wei Zhou, Zhongke Bai, Yingui Cao, Yuhan Huang, Hongyuan Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil nutrients are critical indicators of land reclamation effects and play significant roles in soil restoration in degraded mining areas; however, few studies have analyzed the characteristics and variations in soil nutrients after reclamation in ecologically fragile regions on the Loess Plateau. To analyze the spatial and temporal variations in reclaimed soil nutrients, an experimental field was established in an inner reclaimed dump consisting of four land use types (cultivated land (CL), forestland (FL), grassland (GL), and barren land (BL)) in the Antaibao mine on the Loess Plateau of China. Sampling was conducted in 2013 and 2017, with 78 and 81 sampling points, respectively. The soil available phosphorus (SAP), soil available potassium (SAK), soil total nitrogen (STN) and soil organic matter (SOM) contents at depths of 0–20 cm were measured at each sampling point, and the variations in soil nutrients were analyzed using two-way multivariate analysis of variance, geostatistical analysis, and correspondence analysis. This study revealed the following: (1) All the reclaimed soil nutrients tested increased between 2013 and 2017. (2) There were significant differences in the SAP, SAK, STN and SOM contents among land use types and reclamation ages, and land use type and reclamation age had an interaction effect on the reclaimed soil nutrients. (3) The spatial distributions of the SAP, SAK, STN and SOM contents in 2017 were significantly different from those in 2013 but were almost consistent with the distributions of soil nutrient changes between 2013 and 2017. (4) The most improved SAP, SAK, STN and SOM (SAP-VI, SAK-VI, STN-VI, and SOM-VI) were predominantly distributed in the GL, and there was no obvious trend for the other land use types. These findings are significant for the restoration of reclaimed soil nutrients and provide reasonable land use type options for land reclamation in coal mining areas, especially in ecologically fragile areas on the Loess Plateau.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219305697-ga1.jpg" width="449" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Nozomi Hatano, Kohki Yoshida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The collaborative study between descriptive paleopedology and sedimentology for the Pliocene sediments in southwest Japan clarified the paleo-groundwater table at lake margins and the change of the paleoclimatic conditions in the coastal region of eastern Asia during the Pliocene period (3–4 Ma). Some hydromorphic paleosols were formed in the proximal floodplain and the natural levee, which are generally located in a high-topographic position, and these paleosols finally reached a similar maturity to ultisol and inceptisol. The vertical variation of the sedimentary facies suggests the increased sedimentation rates and increased volume of sediment supply during this period. The stratigraphic distribution of the hydromorphic paleosols in the Pliocene formation implies the rising of the paleo-groundwater table and to become considerably fluctuating of the paleo-groundwater table. The temporal change in weathering conditions implies that precipitation increased during the middle Pliocene warm period.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): M.L. Rodríguez-Blanco, M.M. Taboada-Castro, M.T. Taboada-Castro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉During the winter of 2013/2014, a sequence of explosive cyclogeneses occurred in NW Spain, causing severe flooding and substantial economic damage. Peak discharges were extremely high in many areas, with return periods in excess of 2–5 years. The heavy flow registered during these episodes provides a unique opportunity to evaluate the sedimentological effects resulting from high-magnitude flow events. Such events are relatively rare and the technical difficulties in sampling with sufficiently high frequency means that few observations on sediment transport can be gathered during the same. In this study, we present detailed hydrological and sedimentological observations across a period of consecutive explosive cyclogeneses from two small-sized catchments (i.e., the Corbeira stream and headwater of the Mero river) located in Galicia (NW Spain), in order to examine the factors controlling suspended sediment (SS) dynamics during high-magnitude flow events. The study sites are representative of the biophysical conditions (e.g. rainfall pattern, land use, vegetation cover and management practice) in NW Spain. The catchments of the Corbeira stream and headwater of the Mero river are similar with respect to climate, land use and management practice. The main differences are the distribution of land use and catchment size (Corbeira: 16 km〈sup〉2〈/sup〉 and Mero: 65 km〈sup〉2〈/sup〉).〈/p〉 〈p〉Large amounts of sediment were transferred in both catchments in response to flow events. A high variability in SS load during these was also observed in the two catchments, which is attributed to variation in rainfall characteristics, magnitude peak discharge, antecedent conditions controlling sediment availability, and suggests that sediment supply and transport vary widely over time. Higher concentration and variability of SS was observed in the Corbeira catchment. Differences in SS dynamics were also noted between the catchments that may be attributed to differences in the spatial distribution of land use, which influence the location of the erosion source and SS availability, and directly and indirectly affects connectivity between the sediment source area and the stream. In the Corbeira catchment, the SS load was closely linked to the hydrological response and rainfall, whereas in the Mero basin, preceding conditions, i.e. the sediment depletion during the previous events, played an important role. The results demonstrated that peak SS concentrations may coincide with, or lag behind, peak discharge, and factors other than discharge (mainly the location of the sediment source and its connectivity with the drainage network) have a major influence on SS concentrations.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Guohua Wang, Seth M. Munson, Kailiang Yu, Ning Chen, Qianqian Gou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Oasis-protection systems are created globally to reverse land degradation in drylands and improve ecosystem condition. This study assessed the effects of a 40-year oasis-protection system on soil physicochemical and plant community properties along a gradient from prohibited grazing to fenced shrublands, to shrub- and tree plantation belts in arid northwestern China. We found that compared with shifting dunes in unprotected desert settings, the wind velocity and sand transportation rate decreased by 75 and 98% when spring storms passed through the most protected shrub- and tree- plantations in the oasis-protection system, respectively. The fraction of silt and clay content, and soil carbon, total nitrogen, and total phosphorus significantly increased along the protection gradient, and reached their highest levels at the most protected belts. Meanwhile, an annual herbaceous plant community developed, and the densities, covers, and biomasses of herbaceous plant species increased with soil nutrients along the gradient. However, a significant increase in soil salinity, sodicity, and desiccation occurred at the shrub- and tree plantation belts, and shrub and tree species introduced in the plantations failed to regenerate after 40 years. Our results demonstrate that the positive effects of oasis-protection systems need to be weighed against the long-term negative consequences of soil salt accumulation and desiccation that can occur in frequently used shrub- and tree plantations, which limits future plant regeneration and ecosystem recovery.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219305168-ga1.jpg" width="257" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Remus Prăvălie, Cristian Patriche, Ionuţ Săvulescu, Igor Sîrodoev, Georgeta Bandoc, Lucian Sfîcă〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Land degradation is a major environmental issue affecting numerous countries worldwide, including certain European states. An in-depth understanding of this complex process’s spatial pattern requires multicriteria approaches such as MEDALUS (Mediterranean Desertification and Land Use) model, which can be extremely useful in identifying lands that are sensitive to degradation in countries that have yet to be explored in this respect, such as Romania. This paper aims to apply the well-established MEDALUS methodology for the first time in a nationwide analysis of Romania, based on various spatial data used as main indicators and sub-indicators (environmental parameters) considered to be driving forces of land degradation. The study aims to map and statistically assess lands with different degrees of sensitivity to degradation, considering seven main environmental quality indicators, four of which are featured in the original MEDALUS method (Climate Quality Index – CQI, Soil Quality Index – SQI, Vegetation Quality Index – VQI and Management Quality Index – MQI), while three were proposed and added (Water Quality Index – WQI, Geomorphological Quality Index – GQI and Anthropic Quality Index – AQI) in order to capture the particularities of potentially degraded lands in Romania as accurately as possible. The seven quality indicators were processed by considering 24 geographical parameters, 14 of which were featured in the standard MEDALUS method, while 10 parameters were added in order to reflect the specific land degradation conditions in Romania. The final results, analysed using the Land Degradation Sensitivity Index (LDSI), showed that 29% (~68,600 km〈sup〉2〈/sup〉) of the country’s total area is critically sensitive to degradation, if considering the most complex LDSI model, assessed based on all biophysical/natural (CQI, SQI, GQI, VQI and WQI) and anthropogenic (MQI and AQI) indicators. If considering the LDSI obtained based only on biophysical indicators (which highlight the natural degradation of lands, not directly influenced by anthropogenic pressures), then only 18% (~42,400 km〈sup〉2〈/sup〉) of Romania’s territory is critically susceptible to degradation. Spatially, it was found that extra-Carpathian areas are by far the most heavily threatened by degradation. The results provide a full overview of this process in Romania and can constitute a basic scientific support for implementing current and future policies aimed at fighting the negative ecological and socio-economic effects of this disrupting environmental process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Josu Narbarte-Hernández, Eneko Iriarte, Carlos Rad, Carlos Tejerizo, Javier Fernández Eraso, Juan Antonio Quirós-Castillo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cultural landscapes are the result of human societies interacting with their environment, which is reflected in the onset and evolution of social practices such as settlement and agricultural production. This paper discusses the results of a transdisciplinary research program carried out on the vineyard landscape of the Rioja Alavesa district, one of the main wine-producing regions of Spain, focusing on the deserted village of Torrentejo (Basque Country, Spain). The study of archival records, combined with extensive archaeological survey and excavation, as well as the intensive analysis of geoarchaeological core samples, permitted the reconstruction of a long sequence of human settlement and agricultural practices extending over ~4000 years. The oldest documented records refer to a Chalcolithic occupation, developed on a buried gypsisol and possibly related to the climatic event at 4.2 ka BP. After a long hiatus, four phases of landscape transformation were documented above this Chalcolithic occupation: (1) the formation of a nucleated village in the Early Middle Ages, represented by the construction of a terraced agricultural landscape, and its passage under the control of different seigneurial powers over the High Middle Ages; (2) the abandonment of the village during the Late Middle Ages and the subsequent concentration of settlement in the charted town of Bastida; (3) a complete reorganisation and expansion of the local terraced systems in the 18th–19th centuries, in a context of specialisation and commercialisation of agricultural production; and (4) present-day mechanisation and capitalisation. These results therefore offer an interesting overview on the complexity and diversity of the historical trends that lie beneath the vineyard landscape of Torrentejo, proving the value of interdisciplinary research approaches for the investigation of the role of human settlement and agriculture in the formation and evolution of agricultural landscapes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Dong Wang, Xinxing Li, Defu Zou, Tonghua Wu, Haiyan Xu, Guojie Hu, Ren Li, Yongjian Ding, Lin Zhao, Wangping Li, Xiaodong Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Permafrost regions store a large amount soil organic carbon (SOC), and the decomposition of these carbon pools can release greenhouse gases and further strength climate warming. An explicit spatial distribution of SOC is one of the basic databases for Earth System Models. However, efficient approaches for obtaining the spatial distribution of SOC remain challenging, especially in mountainous areas which are characterized by complex terrains. Here, we modeled the spatial SOC distribution using the geographically weighted regression (GWR) approach in an area on the eastern part of the Qinghai-Tibetan Plateau (QTP). We analyzed multiple environmental variables and soil profile data (n = 73) to find the best prediction models for the SOC density (SOCD) for the 0–50 cm layers. The results showed that normalized difference vegetation index (NDVI), elevation, and slope gradient are the significant predictors for the SOCD. For the upper 50 cm soil layers, the SOCD ranged from 1.08 to 18.32 kg·m〈sup〉−2〈/sup〉, with higher values in mountain slopes but lower values in mountain valleys and basins. The GWR model had a higher prediction accuracy in the modeling SOCD in comparison with other models such as ordinary kriging (OK) interpolation, multiple linear regression (MLR) model. Our results showed that GWR model is a useful tool for modeling of SOC distribution and potentially can be integrated into Earth system models in areas of complex terrains.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 188〈/p〉 〈p〉Author(s): Jing Hao, Guangyao Xu, Li Luo, Zhong Zhang, Haolu Yang, Hongyuan Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vegetation coverage in coastal wetlands has been significantly altered in response to multiple disturbances over recent decades. However, the major driving factor of vegetation coverage in coastal wetlands remains unclear, with natural and human factors playing interactive roles at the national scale. To identify the major controls of vegetation coverage in coastal wetlands, structural equation modeling (SEM) was conducted to quantify the relative contribution of natural and human factors to vegetation coverage in coastal wetlands in China over a 16-year period (2000–2015). The results showed that, in brief, vegetation coverage was slightly degraded (〈em〉k〈/em〉 = −0.0035) over the 2000–2015 period. The area with a probability of vegetation coverage degeneration ≥80% covered 16.6% of the study area. Most annual mean vegetation coverage was lower but improved near the sea, with inverse results obtained near land. In 2000, human1 (population and GDP, 〈em〉r〈/em〉 = −0.31) and topography (〈em〉r〈/em〉 = 0.32) were the major controls of vegetation coverage. The vegetation coverage (2000) played the most important and positive role (〈em〉r〈/em〉 = 0.62, 〈em〉r〈/em〉 = 0.66) in the vegetation coverage in 2015. Our findings highlight that the major drivers of vegetation coverage in coastal wetlands changed with time and selected variables.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219305715-ga1.jpg" width="273" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Francisco L. Pérez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Rolling mosses of 〈em〉Grimmia longirostris〈/em〉 Hook. were studied in Páramo Piedras Blancas, a high Andean area in Venezuela, using a geoecological research framework focused on interactions between geomorphic, ecological, and soil processes. Spatial patterns of mosses were analyzed downslope from granitic outcrops on three slopes at 4445–4480 m elevation. Fragments from epilithic mosses on the apex outcrops were the source of other mosses. Distance of moss transport below rocks was measured at all sites; mosses on the gentlest (≤4°), 34 m-long, slope were censused along a belt transect on 17 contiguous quadrats; density of moss growth forms, stone size, percent of bare-soil cover, and surface soil properties were determined. Surface clast morphology and profile characteristics of a periglacial stone pavement at the slope base were also examined. Mosses on this site included four growth forms: epilithic mosses on outcrops; mobile, rolling moss balls; epilithic mosses on loose clasts; and unattached elongated mosses. Moss balls (density: ≤0.87 mosses/m〈sup〉2〈/sup〉) lay on upper-transect plots over bare soils (≤92% cover) disturbed by needle ice. Soils here contained ~43–51% fine grains (≤0.063 mm) and 2.9–5.9% organic matter; this made them exceptionally prone to ice segregation and needle-ice formation. Lower-transect plots showed 78–100% stone cover—cobbles and blocks—but little exposed soil; mosses attached to loose clasts were exceedingly abundant (≤31/m〈sup〉2〈/sup〉) on this section. Unattached elongated mosses, often resting along boundaries between adjacent stones, were also common (≤5.5/m〈sup〉2〈/sup〉). The basal stone pavement showed a shallow (≤7 cm) rock veneer over a 24 cm-thick profile with exceptionally fine soil—up to 83.2% fine grains, ≤8.6% organic matter.〈/p〉 〈p〉A conceptual developmental model emphasizing the close linkages among the spatial distribution of mosses, patterns of surface clasts, and characteristics of soils and stone pavements is proposed: (i) Stones and mosses are transported downhill by needle ice and other frost agents; moss fragments gradually assume a globular shape, forming rolling moss balls. (ii) When these reach the stones and pavements on the basal slope, they cannot be transported any further, and remain immobile. (iii) Some mosses come to rest along boundaries between stones and develop into unattached elongated mosses or, (iv) they may become gradually attached to cobbles on the stone pavement; clasts with epilithic mosses can continue moving toward the basin floor. (v) Some mosses become fragmented and provide a source of elongated mosses, or remain partially attached to clasts. Stone pavements develop by a combination of rock accumulation following needle-ice transport, rock upheaving and sorting by ground frost, slope runoff, and downward soil illuviation.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Qihua Ran, Xinyi Zong, Sheng Ye, Jihui Gao, Yanyan Hong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Along with big floods, the heavily loaded sediments have caused devastating social and economic impairments in the Yellow River Basin (YRB). However, the regional differences in the dominant mechanisms for these extreme events haven’t been fully understood. This study selected 68 hydrological stations in the YRB to examine the seasonality of annual maximum rainfall, runoff and sediment events to explore the dominant factors of the extreme flow and sediment events. Our results show that all the extreme events are concentrated in July and August with limited inter-annual variability. The flood occurrence is usually consistent with extreme rainfall events, especially the weekly precipitation. The extreme sediment events are more closely correlated with precipitation than discharge in the Middle of YRB. While at the main stem of Yellow River and outlets of major tributaries, sediment storage in channel takes over the dominance in extreme sediment events.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Makoto Matsuzawa, Masahiro Chigira〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We conducted a multifaceted analysis of the weathering zones of arenite, containing a minute amount of calcite cement, based on mineralogical, chemical, and physical properties. The survey targeted sandstone with mudstone interbeds belonging to the Cretaceous Izumi Group. The survey revealed that the weathering mechanism is a chain reaction; the most important process is the pore opening between the grains caused by the dissolution of calcite cement in the initial stage of weathering. Subsequently, the pores between the grains connect and widen, separating the sand grains within the sandstone. This primary weathering action may be a major difference from wacke. During calcite dissolution in the initial stage, sulfuric acid generated by pyrite oxidation in sandstone plays an important role. Chlorite breaks down as calcite dissolves; however, iron resulting from the breakdown disappears only after the pore water has been replaced by acidic water.〈/p〉 〈p〉Sandstones with advanced diagenesis are dense and hard, and it was previously assumed that thick weathering zones could not develop because they were less susceptible to weathering. However, we discovered that weathering caused arenite with a minute amount of calcite cement to disintegrate into grains down to a depth of 30 m. The surface layer of the weathered arenite lost fine particle fraction and crept to form a fragile soil layer susceptible to landslides.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Sigit D. Sasmito, Yakov Kuzyakov, Ali Arman Lubis, Daniel Murdiyarso, Lindsay B. Hutley, Samsul Bachri, Daniel A. Friess, Christopher Martius, Nils Borchard〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mangrove organic carbon is primarily stored in soils, which contain more than two-thirds of total mangrove ecosystem carbon stocks. Despite increasing recognition of the critical role of mangrove ecosystems for climate change mitigation, there is limited understanding of soil organic carbon sequestration mechanisms in undisturbed low-latitude mangroves, specifically on organic carbon burial rates and sources. This study assessed soil organic carbon burial rates, sources and stocks across an undisturbed coastal mudflat and mangrove hydrogeomorphological catena (fringe mangrove and interior mangrove) in Bintuni Bay, West Papua Province, Indonesia. 〈sup〉210〈/sup〉Pb radionuclide sediment dating, and mixing model of natural stable isotope signatures (δ 〈sup〉13〈/sup〉C and δ〈sup〉15〈/sup〉N) and C/N ratio were used to estimate organic carbon burial rates and to quantify proportions of allochthonous (i.e., upland terrestrial forest) and autochthonous (i.e., on-site mangrove forest) organic carbon in the top 50 cm of the soil. Burial rates were in the range of 0.21–1.19 Mg C ha〈sup〉−1〈/sup〉 yr〈sup〉−1〈/sup〉. Compared to the fringe mangroves, organic carbon burial rates in interior mangroves were almost twice as high. Primary productivity of C〈sub〉3〈/sub〉 upland forest vegetation and mangroves induced soil organic carbon burial in interior mangroves and this was consistent with the formation of the largest organic carbon stocks (179 ± 82 Mg C ha〈sup〉−1〈/sup〉). By contrast, organic carbon stored in the fringe mangrove (68 ± 11 Mg C ha〈sup〉−1〈/sup〉) and mudflat (62 ± 10 Mg C ha〈sup〉−1〈/sup〉) soils mainly originated from upland forests (allochthonous origin). These findings clearly indicate that carbon sequestered and cycling in mangrove and terrestrial forest ecosystems are closely linked, and at least a part of carbon losses (e.g., erosion) from terrestrial forests is buried in mangrove ecosystems.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219305569-ga1.jpg" width="400" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 188〈/p〉 〈p〉Author(s): Jinqiu Ren, Mingdeng Zhao, Wei Zhang, Quanxi Xu, Jing Yuan, Bingjiang Dong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Peak sediment transport during flood events is very important to the sustainability of the Three Gorges Reservoir (TGR), and thus, in-depth research on peak sediment transport must be performed for the refined regulation of this reservoir. The variation in peak sediment transport and its corresponding causes following the completion of the cascade reservoirs in the lower Jinsha River in the TGR are still unclear. In this study, based on daily discharge and suspended sediment concentration time series, hysteresis patterns and peak sediment transport times were used to determine the peak sediment transport variations. The temporal peak sediment transport variations and their origins were revealed based on wave theory and a one-dimensional hydraulic model. The results show that peak sediment hysteresis has become more obvious recently, and the greatest influencing factor is the construction of cascade reservoirs. Rising water levels in the TGR contributed to slowing SSC, doubling the proportion of anti-clockwise patterns, and increasing the peak sediment transport time by approximately 31% after 2003. The cascade reservoirs in the lower Jinsha River reduced the peak discharge by approximately 15%, which had a relatively large influence on the SSC peak, increasing the SSC peak transport time by approximately 22% and increasing the proportion of the anti-clockwise pattern at the inflow reach. These results can provide references for reservoir regulation during flood events; more significant sediment hysteresis means the regulation timing should be changed. The lag between the peak sediment and peak discharge is affected by the flow process and water level and can be used to help develop a reservoir regulation model.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 187〈/p〉 〈p〉Author(s): Michael Tobias Löbmann, Rita Tonin, Camilla Wellstein, Stefan Zerbe〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Herbaceous vegetation is an important factor for control of shallow slope failure. While roots of herbaceous vegetation rarely cross potential shear planes, they increase soil cohesion in the top soil and create a surface-mat effect. The surface-mat is a dense layer of laterally interwoven plant fibers, which create considerable horizontal tensile strength of the top soil. Through redistributing impacting forces from unstable towards stable slope areas, the surface-mat can prevent shallow slope failure.〈/p〉 〈p〉We present a method for measuring the horizontal tensile strength of the top soil, which estimates the surface-mat effect. On four montane grassland slopes in Northern Italy, grass sods were cut out from the soil and their tensile strength was measured with a traction machine. The scope of this study is to investigate potential soil physical and biological factors influencing slope stability. Generally, the surface-mat effect decreased with soil depth. Bulk density, soil moisture and aboveground vegetation parameters showed no correlation with the surface-mat effect. Root length density was weakly correlated. Soil water saturation had a marginally significant negative correlation (p 〈 0.1) when root length density was low, but no correlation when root concentration was high. Vegetation type and management influenced the surface-mat effect. We conclude that the low influence of wet conditions on the surface-mat effect makes it a promising strategy for shallow erosion control. In addition, our findings suggest, that specific vegetation management can increase the surface-mat effect.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: May 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 188〈/p〉 〈p〉Author(s): Xiao-Dong Song, Feng Liu, Hua-Yong Wu, Qi Cao, Chen Zhong, Jin-Ling Yang, De-Cheng Li, Yu-Guo Zhao, Gan-Lin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Over the last three decades, both the crop yields and population in China have steadily increased due to continued agricultural investments. K fertilizer and the return of straw have played vital roles in the yield and quality of crops. However, the effects of long-term fertilization on soil K to a soil depth of 1 m have received little focus, and unbalanced K fertilization frequently occurs because local farmers lack sufficient information about soil K. In this study, the spatial distribution of available potassium (AK) in East China was predicted using kriging with external drift (KED) and random forest (RF) techniques. A comparison of the trends in the 1980s and 2010s showed that the mean AK values in East China generally increased. The mean AK values at soil depths of 0–20 cm, 20–50 cm and 50–100 cm increased by 17%, 12% and 23%, respectively, and the AK stocks increased from 0.14 Pg to 0.17 Pg. However, the spatial patterns of AK at the regional scale suggested that approximately 68.12% of the study area lacked AK. AK deficiency was found in Northeast and South China. The ratios of AK concentrations in the subsoil to those in the topsoil suggested that less K was stored in the subsoil than in the topsoil. Relatively more AK was found in the subsoil (20–50 cm) of paddy fields in the middle of East China than in the other areas. The maps produced in this study could be used to support the decisions of regional agriculture management, and our study demonstrates that effective K fertilizer application in East China should be taken into consideration.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Gordana Kaplan, Ugur Avdan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉As one of the most important ecosystems, wetlands are threatened from both natural and anthropogenic activities. Mapping wetland is one of the curtail needs in order to prevent further loss. Since the beginning of the Remote Sensing revolution, different approaches using satellite images have been used for mapping and monitoring wetlands.〈/p〉 〈p〉In this paper we investigate the potential of the recently launched Sentinel satellites, both separate and in combination, for accurately mapping of different wetland classes using Support Vector Machines (SVMs) learning classifier. For investigating the influence of the Sentinel-2 red-edge bands, and the radar bands from Sentinel-1, three different datasets have been analyzed.〈/p〉 〈p〉The results showed that for more accurate mapping of different wetland classes, different datasets should be used. Thus, the red-edge bands have significant influence over the intensive vegetated wetland classes such as swamps, and the radar bands have significant influence over partially decayed vegetated wetland areas such as bogs. For future studies, in addition to the analyzed datasets, we recommend adding and investigating several vegetation indices for mapping and monitoring wetland areas.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Komeil Rokni, Tajul Ariffin Musa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vegetation indices have been developed to characterize and extract the Earth's vegetation cover from space using satellite images. For detection of vegetation changes, temporal images are usually independently analyzed or vegetation index differencing is implemented. In this study, a vegetation change index, named normalized difference vegetation change index (NDVCI), was developed to directly detect vegetation changes between two different time images with improved accuracy. The effectiveness of the proposed method to detect vegetation changes was evaluated in comparison with that of enhanced vegetation index (EVI) differencing and normalized difference vegetation index (NDVI) differencing methods at seven test sites under different environmental conditions in Iran, Malaysia, and Italy. Landsat imagery as one of the most widely used sources of data in remote sensing was used for this purpose. Overall accuracy, kappa coefficient, and omission and commission errors were calculated to assess the accuracy of the resulting change maps. The results demonstrated superiority and higher performance of NDVCI compared to EVI and NDVI differencing for detection of vegetation changes. In five out of the seven test sites, the classification accuracy of NDVCI was higher compared to that of the other methods. In contrast, the results revealed lower accuracy of EVI differencing for vegetation change detection at all the test sites, while NDVI differencing was superior at two of the test sites. In conclusion, the study demonstrated great performance of NDVCI for monitoring vegetation changes at different environmental conditions. Accordingly, this technique may improve the vegetation change detection in future studies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Roberto Avelino Cecílio, Stefania Marques Pimentel, Sidney Sara Zanetti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉There are many controversies about the effect of forest cover on basin streamflows. The objective of this paper was to use the Soil and Water Assessment Tool (SWAT) to provide hydrological modeling of streamflows of a Brazilian Atlantic Rainforest watershed, simulating land use change scenarios with increasing and decreasing forest cover. Regarding the afforestation scenarios, the influence of the geographic location on the afforestation was also evaluated through two approaches: a) a “random” approach (RA), in which the location of reforested areas does not matter; and b) an “imposed” approach (IA), in which the geographical positions of the afforestation are precisely defined. The RA results showed little tendency of reduction in the simulated average and minimum flows with the afforestation. The IA approach showed that the geographic position of afforestation did not significantly interfere in the average flows, but interfered in the simulated minimum flows. Afforestation concentrated in areas close to streams caused a reduction in minimum flows, while its concentration in the upper parts of the basin managed to increase them.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Pierluigi Confuorto, Diego Di Martire, Donato Infante, Alessandro Novellino, Raffaele Papa, Domenico Calcaterra, Massimo Ramondini〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques have repeatedly proved to be an effective tool for built environments monitoring in areas affected by geological hazards. This paper describes how the Coherent Pixel Technique (CPT) approach has been successfully applied to assess the response of an unstable slope to the different phases of remedial works following a landslide event. The CPT technique was performed on 59 COSMO-SkyMed images obtained between May 2011 and August 2016 and centred on the Quercianella settlement (a small hamlet of Livorno municipality, Tuscany, Italy), where the reactivation of a dormant shallow slide had occurred in March 2011 and, hereafter, a geotechnical intervention, designed with the aim of mitigating the risks, has been conducted from August 2013, lasting thirteen months. The time series of CPT results show a deformation pattern with sudden accelerations (up to 21 mm in few months) corresponding to the beginning of the interventions, during which the area has been excavated to install a drainage well, followed by mild decelerations resulting from the stabilization of the area after the conclusion of the works. In particular, the integration of ground-based subsurface monitoring (inclinometers and piezometers) and DInSAR superficial data has provided consistent results for landslide characterization and helped defining the state of activity and the areal distribution of the sliding surface. Moreover, the performance of remedial works in the landslide-affected area has been observed, showing stabilization in the upper part of the hamlet and the ongoing movement in the lower part. The combined monitoring system also led the geotechnical company in charge of remedial works to design further stabilization works in order to preserve buildings and roads in the moving area. Therefore, the integration of remote sensing techniques and in situ instruments represents a timely and cost-efficient solution for intervention works monitoring, opening new perspectives on designing engineering solutions for the stabilization of unstable slopes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Tianyang Li, Siyue Li, Chuan Liang, Binghui He, Richard T. Bush〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil detachment capacity (Dc) is a key parameter in many soil erosion models and is typically estimated using hydraulic parameters. However, the accuracy of predicting Dc and its relationship to hydraulic characteristics remains poorly understood for many soil types. This study investigates the predictability of Dc with hydraulics by simulated scour rill flow and quantifies erosion vulnerability to rill erosion as reflected by rill erodibility and critical hydraulic values for an Entisol from Southwestern China. Small samples (10 cm in diameter, 6 cm in depth) of sandy clay loam of Entisol were subjected to scouring by simulated rill flow under the combinations of flow discharges (18.8, 26.3, 46.6, 54.4, 64.6 l min〈sup〉−1〈/sup〉) and slope gradients (3.5%, 8.7%, 17.6%, 26.8% and 36.4%). The results showed that Dc increased as a power function with flow discharge irrespective of slope gradients, and at low discharge gradients Dc increased as a power function with slope and with transitions to a linear function at higher discharge gradients. The association of flow discharges and slope gradients was a better predictor of Dc than flow depths and slope gradients. Shear stress and stream power were similar and better predictors of Dc than flow velocity, unit stream power and unit energy. Rill erodibility related to all hydraulic parameters were significantly different from zero under combination of flow discharges and slope gradients, and this was true for critical hydraulic values related to comprehensive data. Relatively higher rill erodibility and lower critical hydraulic values compared with other soils demonstrated that sandy clay loam of Entisol is susceptible to detachment. These results highlight the erosion vulnerability of Entisols and provide deeper insights on the reliability of hydraulic parameters which strongly affect soil detachment modeling.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219300888-ga1.jpg" width="272" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): C.A. Mushi, P.M. Ndomba, M.A. Trigg, R.M. Tshimanga, F. Mtalo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study uses the Global Assessment of Soil Degradation (GLASOD) to map sediment sources and erosion process types within the Congo Basin as part of a scoping study to guide a basin wide sedimentation study. The GLASOD map is validated using information from literature and published sediment concentration data at the Brazzaville gauging station, which includes over 95% of the basin area. Validation is complemented by analysis of timelapse satellite images and surface water transition maps derived from Landsat images. The upper catchments are shown to be the main sources of sediment, with the largest exporter by quantity being the Upper Congo sub-basin followed by the Kasai. In terms of severity, the Kasai has the highest specific sediment production rates at 8.92 t/km〈sup〉2〈/sup〉/year, followed by the Sangha and Upper Congo at 8.52 t/km〈sup〉2〈/sup〉/year and 7.61 t/km〈sup〉2〈/sup〉/year, respectively. The dominant erosion/degradation type is the loss of topsoil through water erosion (sheet erosion), occurring in 32% of the entire Congo Basin area, followed by loss of nutrients and organic matter through chemical degradation, 21% of area. The mapping also shows that a large proportion of the Basin (39%) consists of stable terrain under natural conditions, without any human induced erosion. The erosion levels in the Basin are generally low with the predominant mapped erosion processes occurring mostly infrequently and with low levels of severity. The GLASOD map performs satisfactorily as a tool for mapping erosion sources and process types, but fails to explain the process dynamics within the sub-basins, for example, the high sediment exportation rates published for the Sangha sub-basin despite consisting mainly of stable natural terrain (84%). Analysis of satellite images shows an increase in sediment concentration in the Congo River's waters over the years. However, this temporal increase in sediment concentration is neither reflected in the GLASOD map nor the quantitative studies reviewed for this paper, pointing to the urgent need for future research on sediment dynamics in the Basin. Questions are also raised on the roles of the Malebo Pool and Cuvette Centrale in the sediment transport processes of the Basin. The questions raised, and observations made from this study have been used to identify strategic sampling sites for further field studies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Jenny Richter, Phillip R. Owens, Zamir Libohova, Kabindra Adhikari, Bryan Fuentes〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil mappers have traditionally relied on tacit knowledge and qualitative assessment of soil-landscape relationships to obtain the physiographic context necessary to predict soil distribution and spatial patterns. This assessment implicitly utilizes a nested hierarchical approach based on differences in the phenomenon scale of soil forming factors where climate, landscape, parent material, and topography are examined in sequence to create a model of soil-landscape relationships. Our objective was to predict parent material distribution using expert knowledge paired with quantitative digital terrain attributes as part of a nested approach to digital soil mapping. The study took place at an 890-hectare research farm in Logan County, Arkansas, which is part of the Arkansas River Valley. Two major groups of parent material are identifiable in the Arkansas River Valley: residual sandstone and shale on erosional uplands, and silty/clayey pedisediment in depositional areas. A 5-m digital elevation model was used to derive thirteen terrain attributes for the study site. Three of the terrain attributes, namely topographic position index, multi-resolution valley bottom flatness, and vertical distance to channel network, were utilized as part of a rule-based approach to model parent material distribution based on preliminary reconnaissance and expert knowledge of the area. The model was validated by sampling 20 locations using a conditioned Latin hypercube sampling (cLHS) design to evaluate the prediction accuracy. Seventy-five percent of cLHS samples were accurately predicted to be residuum or pedisediment. The resulting map also had 90% agreement with the National Cooperative Soil Survey map; however, the digital map was able to provide more spatially explicit information especially on inclusions. Incorporating parent material distribution as part of a nested hierarchical approach to digital soil mapping aids in constraining and predicting soil properties, enables a more straightforward examination of physiographic context and can ultimately lead to more accurate digital soil maps for land management.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 177〈/p〉 〈p〉Author(s): A. Abdourhamane Touré, A.D. Tidjani, J.L. Rajot, B. Marticorena, G. Bergametti, C. Bouet, K.J.M. Ambouta, Z. Garba〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In the Sahel, wind erosion increases the vulnerability of sandy soil through the removal of the finest and most fertile fraction of the soil, including nutrients, potentially limiting vegetation development. To provide experimental evidence of the role of different land uses on wind erosion, measurements of horizontal sand fluxes and associated meteorological parameters were taken for four years in Kilakina (southeast of Niger), where large rangeland surfaces coexist with cultivated surfaces and moving dunes in a typical Sahelian semiarid regime (average annual precipitation in the order of ±300 mm yr〈sup〉−1〈/sup〉). The horizontal sand fluxes were monitored using BSNE sediment traps on the three sandy surfaces representative of the main land uses in the region: a cultivated field, a pastured land and a mobile dune. In addition, a meteorological station was installed to monitor the wind speed and direction and rainfall.〈/p〉 〈p〉Saltation flux on the bare mobile dune appeared to be an excellent proxy for wind erosivity in this region. The mobile dune produced saltation fluxes 2 to 40 times higher than the cultivated field and the rangeland. The annual fluxes on the dune varied from 2000 to 6000 kg m〈sup〉−1〈/sup〉 due to the variability of the winds from year to year. The sediment fluxes are higher in the millet field than those on the pastured land due to a larger fraction of bare surface compared to the relatively homogeneous grass cover that exists on pastured surfaces. The vegetation produced in a given year affects the wind erosion of the following year through the effect of dry vegetation and litter cover. These results highlight the sensitivity of wind erosion to dry vegetation, even for low cover rates. This outcome suggests that any agricultural practice that decreases dry vegetation cover, such as the uptake of vegetation residues from the fields and the pastured land, has a strong impact on wind erosion. Wind erosion in East Niger can be higher during the Harmattan season than during the monsoon season, while similar measurements in West Niger showed that saltation fluxes were higher during the monsoon season. This outcome suggests that the intensity of the Harmattan surface winds could decrease from east to west. In addition to land use changes, the regional pattern of the surface winds and its future evolution clearly deserve further investigation based on relevant long-term in situ measurements.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Zi-Qiang Yuan, Xiao-Jin Jiang, Guo-Jun Liu, Hui-Jun Jin, Ji Chen, Qing-Bai Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Alpine meadow degradation is a major environmental problem in the Qinghai-Tibetan Plateau of China. While it is expanding at a rapid pace, quantitative information on the effect of grassland degradation on soil properties remains largely unavailable. This study aimed to evaluate the effect of vegetation cover reduction on soil organic carbon (SOC) and nutrient stocks. A degraded alpine meadow with vegetation cover gradients of 90% ± 6.6% to 70% ± 8.3% and 45% ± 8.7% was selected, and soil samples were collected at two soil depths (0–20 and 20–40 cm depths). The reduction in vegetation cover decreased soil sand, SOC, total nitrogen (N), available phosphorus (P), inorganic N, microbial biomass carbon and N, soil moisture, and the ratio of SOC to available P, but increased soil pH, bulk density, the ratio of SOC to total N, and clay and silt contents. The decline in vegetation cover from 90% to 45% significantly affected SOC, total N, total P, and available P stocks at 0–40 cm soil depths (〈em〉p〈/em〉 〈 0.05, respectively), with losses as high as 3.89 kg m〈sup〉−2〈/sup〉 for SOC, 0.47 kg m〈sup〉−2〈/sup〉 for total N, and 1.05 g m〈sup〉−2〈/sup〉 for available P. These values corresponded to depletion rates at 28.7%, 39%, and 21%. The increases were as high as 39 g m〈sup〉−2〈/sup〉 for total P and corresponded to an increase rate of 15%. The structural stability index had a linear decrease trend with decreasing vegetation cover. The index was 〉9% at the COV90 site and was close to 5% at the COV45 site for 0–20 cm soil depth. These results confirmed that vegetation cover reduction is a key factor that influences the soil nutrient stocks and structural stability of the alpine meadow. The losses in SOC and nutrients by vegetation cover reduction on the alpine meadow can have a remarkable influence on a large scale. Meanwhile, the alpine meadow may have huge carbon and N sequestration potentials duo to the potential increase of vegetation productivity in this area.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Yahya Kooch, Razie Sanji, Masoud Tabari〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The properties of litter and soil, which are probably influenced by vegetation traits, have an effect on the fractions of C and N and ultimately global warming. In this study, litter and soil samples were collected from representative forestlands, including a mixed natural forest dominated by hornbeam‑ironwood and tree plantations of ash, maple, cypress and pine which are situated in a temperate area of Northern Iran. Main litter characteristics, soil aggregation and fractions of C and N were studied. Pine had the highest values of litter thickness (14.46 cm), C (60.31%) and C/N ratio (81.77 and 20.28 for litter and soil, respectively). However, litter N (2.20%), micro aggregates of total soil (39.75%), aggregate stability (73.86%) and macro aggregates of total soil (54.87%) were found significantly higher under the natural stands. Total C (2.58%), C in macro and micro aggregates (0.31 and 0.33 respectively), POM-C (4. 68 g/kg), DOC (125.54 mg/kg) and C sequestration (45.34 Mg/ha) were considerably higher under pine (for POM-C, pine ≈ cypress) and the greater values of total N (0.34%), N in macro and micro aggregates (0.10 and 0.08 respectively), POM-N (0.47 g/kg), DON (33.80 mg/kg) and N sequestration (6.86 Mg/ha) were observed under natural stands. Under our conditions, conversion of natural forest is due to reduction of soil N fractions and C increased under pine tree plantations.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Raul-David Șerban, Alexandru Onaca, Mihaela Șerban, Petru Urdea〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Block streams, as common features in the Southern Carpathians, are essential for understanding the evolution of alpine environments. Despite their widespread occurrence, they have frequently been omitted from previous inventories of periglacial landforms and from the general understanding of landscape development. This study evaluated the environmental controls on spatial distribution and dimensions of 2056 block streams for a better understanding of their evolution and climatic significance. Different lithology classes and topographic characteristics were assessed using standard least-square linear regression and one-way analysis of variance (ANOVA). The majority of the block streams belong to the linear morphological type, but six other types of morphologies were found (e.g. sinuous, curved, and braided). Bivariate and multivariate statistical analysis revealed a high density of landforms on southern slopes (59%), granite terrains (47%), and above 1750 m. Large features occur mainly on southern slopes and in areas with granites. Landform dimensions and spatial distribution are influenced to a certain degree by lithology, slope aspect, and elevation, making it difficult to identify a dominant factor. Block streams developed extensively at the end of the Pleistocene under permafrost conditions. Today, these features suggest inactivity, but during the cool episodes of the Holocene (e.g. Little Ice Age - LIA), the formation of block streams above 2100 m was re-initiated. Future absolute dating and monitoring of landform dynamics will support these findings.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219300840-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Simon Drollinger, Yakov Kuzyakov, Stephan Glatzel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Decomposition of organic substances is one of the main processes responsible for the signatures of stable carbon and nitrogen isotopes (δ〈sup〉13〈/sup〉C and δ〈sup〉15〈/sup〉N) in soils and peats. However, the applicability of δ〈sup〉13〈/sup〉C and δ〈sup〉15〈/sup〉N signatures at the natural abundance level as indicators of the degree of peat decomposition is still debatable. We evaluated δ〈sup〉13〈/sup〉C and δ〈sup〉15〈/sup〉N depth patterns of peat cores sampled at nine sites in two nearby Alpine peat bogs with varying degree of organic matter degradation. Based on water table depths and past drainage intensities, the peat cores were divided into three degradation classes. We found similar overall depths patterns of δ〈sup〉13〈/sup〉C and δ〈sup〉15〈/sup〉N across the nine depth profiles and distinct differences between aerobic and anaerobic peat layers. Considerable differences in stable C and N isotope signatures of same depths were detected between profiles of the three classes, whereas depth profiles of peat cores with similar degree in peatland degradation were nearly identical. In the aerobic peat layers, δ〈sup〉13〈/sup〉C and δ〈sup〉15〈/sup〉N increased with depths at all study sites from 2.6‰ to 4.9‰ for δ〈sup〉13〈/sup〉C and 3.2‰ to 7.0‰ for δ〈sup〉15〈/sup〉N compared to the initial signatures of the plant biomass. Standardised δ〈sup〉13〈/sup〉C of aerobic layers differ distinctly between slightly degraded peats at the open peat bog area, intermediately degraded peats at the tree-covered edge areas and strongly degraded peats at the former peat-cutting site. δ〈sup〉13〈/sup〉C signatures of aerobic layers of strongly degraded peats were markedly more negative compared to the slightly degraded peats because of the selective 〈sup〉12〈/sup〉C losses by microbial respiration. δ〈sup〉15〈/sup〉N were more positive at strongly degraded than at slightly degraded sites in both, aerobic and anaerobic peat layers. The uniform stable isotope ratios in the anaerobic layers deeper than the local maxima of the isotopic signatures support the assumption that minor 〈sup〉13〈/sup〉C fractionation occurs under anaerobic conditions. δ〈sup〉13〈/sup〉C slightly declining with depth in the waterlogged layers of strongly degraded peat reflects the preferential utilisation and loss of labile organic compounds enriched in 〈sup〉13〈/sup〉C. δ〈sup〉15〈/sup〉N of strongly degraded peats was higher compared to well-conserved peat. The close relationship between the measured δ〈sup〉15〈/sup〉N to δ〈sup〉15〈/sup〉N modelled based on C:N ratios and bulk densities supports the assumption that the δ〈sup〉15〈/sup〉N signature is the result of isotopic fractionation by peat decomposition. We conclude that peat decomposition strongly affects the δ〈sup〉13〈/sup〉C and δ〈sup〉15〈/sup〉N depth profiles of peat bogs and most likely overrides other factors, such as differences between plant species, litter components, atmospheric δ〈sup〉13〈/sup〉C shift during peat formation, temperature effects, or type of mycorrhizal symbiosis.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): M.J. Uddin, Peter S. Hooda, A.S.M. Mohiuddin, Mike Smith, Martyn Waller〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Land inundation is a common occurrence in Bangladesh, mainly due to the presence of two major river systems – the Brahmaputra and the Ganges. Inundation influences land use and cropping intensity. However, there is little information on the influences of the extent of flooding and cropping intensity has on soil organic carbon (SOC), particularly at the landscape level. To investigate these influences, we collected 268 surface (0–30 cm) soil samples from 4 large sites within the two alluviums deposits (the Brahmaputra river and the Ganges river), on a regular grid (1600 m). The findings show that SOC levels are generally low, reflecting the intensity of agriculture and land management practices. SOC variability was higher across the medium high land (MHL) and medium low land (MLL) sites than in the high land (HL) and low land (LL) sites. The relatively low SOC levels and variability in the HL sites indicate soils here might have reached to equilibrium levels due to higher land use intensity. Topographically higher lands (HL and MHL), due to less of inundation, had higher cropping intensities and lower SOC's than lower lands (MLL and LL), which had lower cropping intensities, as they remain inundated for longer periods of time. The findings clearly demonstrate the intrinsic influence of land inundation in driving cropping intensity, land management practices and SOC levels.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 177〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Furong Niu, Ji Chen, Peifeng Xiong, Zhi Wang, He Zhang, Bingcheng Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pulsed rainfall affects both aboveground vegetation dynamics and belowground biogeochemical processes, such as carbon cycling, in semi-arid regions. In order to study carbon released by soil respiration (SR) after rainfall pulses in natural grassland on the Loess Plateau, a rainfall simulation experiment was conducted in a grassland community co-dominated by a C〈sub〉4〈/sub〉 herbaceous grass [〈em〉Bothriochloa ischaemum〈/em〉 (L.) Keng] and a C〈sub〉3〈/sub〉 leguminous subshrub [〈em〉Lespedeza davurica〈/em〉 (Laxm.) Schindl] in the loess hilly-gully region. Soil respiration rate (〈em〉R〈/em〉〈sub〉s〈/sub〉), soil temperature (〈em〉T〈/em〉〈sub〉s〈/sub〉), and soil volumetric water content (〈em〉S〈/em〉〈sub〉v〈/sub〉) were measured 1 day before and 1, 2, 3, 5, and 7 days after four rainfall treatments (ambient rainfall plus a 5 mm, 10 mm, 20 mm, and 30 mm rainfall pulse) and one control treatment (only ambient rainfall) in June and August 2013. Results showed that 〈em〉R〈/em〉〈sub〉s〈/sub〉 and 〈em〉S〈/em〉〈sub〉v〈/sub〉 largely increased one day after simulated rainfall 〉 5 mm. In June, the peak 〈em〉R〈/em〉〈sub〉s〈/sub〉 under 10, 20, and 30 mm rainfall was 0.80–1.03 μmol C m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 in 〈em〉B. ischaemum〈/em〉, with a 25–62% increase compared with the control treatment, and 0.74–1.0 μmol C m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 (+51–104%) in 〈em〉L. davurica〈/em〉. In August, the peak 〈em〉R〈/em〉〈sub〉s〈/sub〉 was 1.23–1.73 μmol C m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 (+23–73%) and 1.52–1.70 μmol C m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉 (+81–102%) in 〈em〉B. ischaemum〈/em〉 and 〈em〉L. davurica〈/em〉, respectively. The magnitude and duration of the increase in SR were positively related to the rainfall size, and a more considerable increase was observed in August. There was a threshold rainfall (i.e., 5–10 mm) for triggering SR increases in both months. And different responses were found between the two species, there was more substantial SR increases in 〈em〉L. davurica〈/em〉 in comparison to 〈em〉B. ischaemum〈/em〉. After rainfall pulses, soil moisture and soil temperature co-regulated SR. During the relatively dry season (i.e., June), SR was negatively correlated with soil temperature and the temperature sensitivity 〈em〉Q〈/em〉〈sub〉10〈/sub〉 value of SR was small (0.5–0.6), while it changed to positively in August and the 〈em〉Q〈/em〉〈sub〉10〈/sub〉 was largely increased (3.2–4.3). Conversely, soil moisture was positively related to SR in both months and explained a large portion of the variation in SR (32–43% and 42–52% in 〈em〉B. ischaemum〈/em〉 and 〈em〉L. davurica〈/em〉, respectively). These findings indicated that soil moisture was the major environmental factor in controlling SR in this grassland. Overall, our study suggests that SR response following rainfall pulses is species-specific within the grassland community and tends to be controlled by soil moisture, and these should be considered in the regional carbon budget assessment in the background of vegetation rehabilitation and rainfall pattern changes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Xiuqing Nie, Lucun Yang, Fan Li, Feng Xiong, Changbin Li, Guoying Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Alpine shrubland ecosystems in the Three Rivers Source Region (TRSR) store substantial soil organic carbon (SOC), but the storage, patterns and control of SOC in those ecosystems have rarely been investigated. In this study, using data from 66 soil profiles surveyed from 22 sites between 2011 and 2013, we estimated the storage and patterns of SOC, and their relationships with climatic factors, elevation, ground cover and slope. Our results showed that SOC storage in the top 100 cm across the TRSR shrubland was 0.68 ± 0.38 Pg C, with an average SOC density (soil carbon storage per area) of 26.21 ± 14.58 kg m〈sup〉−2〈/sup〉. Spatially, SOC density increased with longitude and latitude. Vertically, SOC in the topsoil at 30 cm and 50 cm accounted for 56% and 75%, respectively, of the total at 100 cm. SOC density showed a decreasing trend with increasing elevation, but it was greater in regions of higher ground cover. The density had no relationship with either mean annual precipitation or slope. Increasing mean annual temperature had positive effects on SOC density, which is inconsistent with the global trend. With increasing soil depth, however, the effects of temperature on SOC density were not significant. Therefore, in a global warming scenario, increasing temperature gives shrubland considerable C sink potential on the topsoil, and the regions of C sequestration differ as a result of uneven increases in temperature. Hence, further monitoring of dynamic changes is necessary to provide a more accurate assessment of potential C sequestration in TRSR shrubland.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): F.J. Blanco-Velázquez, S. Muñoz-Vallés, M. Anaya-Romero〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Contamination has been identified as one of the main threats for soil conservation worldwide. Availability of high-quality information on soil contamination, its impacts and effects is still required at global level. Well documented case studies provide valuable information to understand long-term trends associated with management of contaminated soils. The temporal evolution of contamination and associated factors have been studied in the Guadiamar river basin, after a mine waste spillage of about 6 hm〈sup〉3〈/sup〉 of acidic waters and toxic sludge enriched with trace elements. An extensive database has been compiled, harmonized and standardized from the numerous and heterogeneous sectorial studies and monitoring carried out in the area since 1998, and has been used for spatio-temporal analysis of the effectiveness of individual and mixed soil remediation measures as a pilot case for data exploitation. Database variables consider six ecosystem compartments (soil, water, sediment, air, plant and animal biomass), management (remediation measures applied over time and space), land use and cover, and present and predicted climate. The pilot developed for remediation effectiveness considered 11 different treatments, including mixed addition of compost, red clays and sugar beet lime (SBL). Harmonization and Standardization processes were carried out according to EU-HYDI, INSPIRE and ENVASSO recommendations. However, correlation and regression analyses were applied to standardize pH and Cd values from our case study with R Software. According to the land use, high doses of SBL with other soil amendments don't provide high benefits for the reduction of Cadmium pseudototal. The created database provided a relevant resource of information for the management of the Guadiamar area and other similar cases. Also, the present methodology and harmonized data-based will be useful for soil contamination assessment across Europe allowing the development of decision support tools and decision making for the selection of effective and available remediation strategies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Eduardo Osório Senra, Carlos Ernesto Schaefer, Guilherme Resende Corrêa, Davi Feital Gjorup, João Santiago Reis, Márcio Rocha Francelino〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The high mountains of Central Andean represents one of the most diverse and heterogeneous landscape of South America, with very contrasting climates across an east-west gradient that remains poorly investigated in terms of Late Quaternary soil formation. Climatic forces within a diverse pedogeomorphological framework generates a complex geoenvironmental scenario, extremely susceptible to climatic changes. From the high aridic bolivian altiplano to moist periglacial regions at high mountain, and from these, to the tropical rainforest downslope, one finds soil chronosequences and different ecosystems. The objective of this work was to describe and interpret chronological, morphological, physical, chemical and mineralogical attributes of 18 profiles along a long and representative east-west transect through the Cordillera Real, at altitudes varying between 1800 and 5030 m a.s.l. The parent material is lithologically diverse, ranging from till, fluvio-glacial, talus and loess sediments. Most soils show a sequence of O, A, C and C/R with high organic carbon contents at surface and subsurface, forming Umbric horizons. Buried, polycyclic organic layers are common and the 〈sup〉14〈/sup〉C dating reveals a sequence of processes as one moves away from the glaciated peaks, varying from 1500 to 6000 years (BP). The occurrence of paleo-peatlands and past and present-day hydromorphic areas (bofedales) result in widespread melanization trend, with histic horizons and histosols formation in the bottomlands. The relict, degraded state of bofedales indicates a reduction of waterlogging in the Altiplano in the late Holocene, resulting in increasing water shortage. Inceptisols occur at the high mountain sector, under periglacial conditions and high slope instability and solifluxion. In general soils are acid or high acid, with low base saturation and high Al saturation. High mountain Tundra soils at (5020 m) are exclusively developed on moraines of resistant granodiorite and have low clay content and less mineralogical diversity. Soils at the western slope were affected by the last glaciation and show more diverse mineralogy with cryogenic features under dry, open vegetation (Puna). On the other hand, soils at the eastern slope are associated with a greater climatic variation, varying mineralogical attributes, greater organic carbon mineralization and formation of organometallic complexes. Although most soils show influence of non-crystalline minerals, such as allophanes and amorphous Fe oxides, andic soil properties were apparently absent.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Justine L. Ramage, Daniel Fortier, Gustaf Hugelius, Hugues Lantuit, Anne Morgenstern〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thermokarst results from the thawing of ice-rich permafrost and alters the biogeochemical cycling in the Arctic by reworking soil material and redistributing soil organic carbon (SOC) and total nitrogen (TN) along uplands, hillslopes, and lowlands. Understanding the impact of this redistribution is key to better estimating the storage of SOC in permafrost terrains. However, there are insufficient studies quantifying long-term impacts of thaw processes on the distribution of SOC and TN along hillslopes. We address this issue by providing estimates of SOC and TN stocks along the hillslopes of three valleys located on Herschel Island (Yukon, Canada), and by discussing the impact of hillslope thermokarst on the variability of SOC and TN stocks. We found that the average SOC and TN 0–100 cm stocks in the valleys were 26.4 ± 8.9 kg C m-〈sup〉2〈/sup〉 and 2.1 ± 0.6 kg N m-〈sup〉2〈/sup〉. We highlight the strong variability in the soils physical and geochemical properties within hillslope positions. High SOC stocks were found at the summits, essentially due to burial of organic matter by cryoturbation, and at the toeslopes due to impeded drainage which favored peat formation and SOC accumulation. The average carbon-to‑nitrogen ratio in the valleys was 12.9, ranging from 9.7 to 18.9, and was significantly higher at the summits compared to the backslopes and footslopes (p 〈 0.05), suggesting a degradation of SOC downhill. Carbon and nitrogen contents and stocks were significantly lower on 16% of the sites that were previously affected by hillslope thermokarst (p 〈 0.05). Our results showed that lateral redistribution of SOC and TN due to hillslope thermokarst has a strong impact on the SOC storage in ice-rich permafrost terrains.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Xiong Yao, Kunyong Yu, Yangbo Deng, Qi Zeng, Zhuangjie Lai, Jian Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Masson pine (〈em〉Pinus massoniana〈/em〉) is a typical reforestation species in subtropical China, which plays a key role in soil and water conservation. Site-specific forest management requires an accurate estimation of the soil organic carbon (SOC) stocks, and information about the spatial distribution of SOC stocks is essential for improving the soil quality and ecosystem productivity. We examined the spatial distribution of SOC stocks using 91 soil samples from Masson pine forests in subtropical China. Ordinary kriging (OK) and inverse distance weighting (IDW) methods were used to compare the spatial patterns of the SOC stocks. A moderate spatial dependence of the SOC stocks suggested that extrinsic and intrinsic factors affected the SOC stocks. Similar spatial distributions but different cross-validation accuracies indicated that OK outperformed IDW. The soil pools at a depth of 0–60 cm were 774.06 Gg and 761.61 Gg as determined by the OK and IDW methods, respectively, which were higher than that measured by the conventional method (CM, 734.22 Gg). This highlights the need to apply different methods when studying the regional SOC pools. On the basis of the comparison of OK, IDW, and CM methods, OK is recommended for determining nonhomogeneous sampling point distributions. The present results enhance our understanding of method selection when studying the spatial distribution of SOC stocks.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 178〈/p〉 〈p〉Author(s): Xiao Jin Jiang, Chunfeng Chen, Xiai Zhu, Sissou Zakari, Ashutosh Kumar Singh, Wanjun Zhang, Huanhuan Zeng, Zi-Qiang Yuan, Chenggang He, Shuiqiang Yu, Wenjie Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The soil hydrological process plays an important role in transporting and distributing water in soils. However, the correlation between water flow behaviors, soil physical properties, infiltration patterns of soil exhibiting different soil layers, and the variation patterns in water flow behavior in rubber-based agroforestry systems remain poorly understood. Here, we mainly used dye-tracer infiltration to classify water flow behavior and HYDRUS-3D to interpret variation patterns of water flow behaviors in a rubber-based agroforestry system in southwest China. The results showed that (1) the soil of forestry patches under 〈em〉Hevea brasiliensis〈/em〉 (HB) and 〈em〉Citrus reticulata〈/em〉 (CR) exhibited better soil physical properties than those with no vegetation (NV). Compared with these in the NV, the saturated soil water content and field capacity increased by 15% and 21% in CR, and by 2% and 12% in HB, respectively; while the saturated hydraulic conductivity enhanced by 584% (〈em〉p〈/em〉 〈 0.001) in the CR plot and by 226% (〈em〉p〈/em〉 〈 0.001) in the HB plot. Correlation analysis shows that the soil bulk density, noncapillary porosity and capillary porosity significantly affected the field capacity, saturated water-holding capacity, and saturated hydraulic conductivity. (2) the general infiltration capacity of the whole soil profile, its order of continuity and the degree of connectivity of preferential flow path networks followed the order of CR 〉 HB 〉 NV. Finally, (3) the infiltration flow in soil under HB and CR exhibited a faster downward wetting front and an obvious lateral flow. These infiltration patterns compensated for the insufficiency of soil water in NV and finally caused water redistribution to be more homogenized across the whole soil profile. Therefore, our findings indicated that the rubber-based agroforestry system is a successful approach for conserving water and reducing runoff in tropical regions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Giora J. Kidron〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is generally accepted that biological soil crusts promote the growth of vascular plants. Nevertheless, contradictory results were recently found for annual plants in the extreme desert dunefield of the Negev (average precipitation of 95 mm) during extreme drought years, explained by the lower available water content (AWC) under the low-albedo biocrusted surfaces at the interdune (ID). Trying to assess whether the biomass and fecundity of the annual plants is higher at the non-crusted dune crest (CR) in comparison to ID also during years with near-average precipitation, surface stability, rain, AWC, fine (silt and clay) content (FC), and soil organic carbon (SOC) were measured in a pair of plots established in CR and ID in two dunes and interdunes. The research was conducted for three years (2009/2010, 2013/14 and 2014/15), having a mean precipitation of 109.4 mm. At the end of each winter, sampling of the annual plants (cover, density, species composition, biomass) took place at CR and ID at 30 cm-diameter miniplots (miniplot-scale), while the biomass and fecundity of 50 randomly-chosen individuals that abundantly inhabited both habitats during the same year were measured at parallel transects (individual plant-scale). Significantly higher cover and generally higher diversity characterized the plants at ID at the miniplot-scale, explained by the higher surface stability. Although characterized by lower FC and SOC, significantly higher biomass and fecundity characterized the individual plants at CR, explained by the higher AWC. Biocrusts were found to have a dual effect on the annual plants: positive due to increased surface stability (cover and for most years also diversity) at the miniplot-scale, and negative due to reduced AWC (low biomass and fecundity) at the individual plant-scale. The higher biomass and fecundity of the individual plants at CR point to the cardinal role played by water (rather than SOC) in this low-nutrient extreme desert. As far the annual plants are concerned, these findings also point at the fact that moderate crust destruction (such as by light trampling) may not necessarily be hazardous to the ecosystem, as it may increase fecundity and subsequently germination success.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): M.J. Wilson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Parent material/mineralogy is widely recognized as an important soil-forming factor along with climate, biota (vegetation), relief (drainage) and time. Bearing in mind that mineral soils, by definition, consist predominantly (usually 〉95%) of mineral particles and control many soil properties, it is surprising that international soil classification systems attribute a relatively insignificant role to the parent material factor. How this situation has come about is briefly reviewed in a historical context, focusing particularly on the contributions of Dokuchaiev in Russia and of Hilgard in the USA. It is argued that the parent material/mineralogy of mineral soils could be used to far greater effect than currently, as a prominent refining factor in soil classification, and as a means of explaining the physico-chemical characteristics of soil units in the contexts of agricultural, environmental and geological studies. More detailed characterization of the hitherto neglected silt fraction could make a significant contribution to such studies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): G. Cecchini, A. Andreetta, A. Marchetto, S. Carnicelli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Acidification is a major soil-forming process, and concerns about acidifying anthropogenic atmospheric deposition make it a significant environmental issue. In the long term, the depletion of exchangeable base cations (BCEs) is the main process underpinning soil acidification. In south-central Italy, acidic soils are not rare and are often located in areas with no excess rainfall over potential evapotranspiration. Many such soils are understood to have been derived from long-term weathering, although whether acidification is an active process remains an open question.〈/p〉 〈p〉Data from the International Co-operative Programme (ICP-Forests) monitoring system revealed that BCE atmospheric deposition was high and stable in south-central Italy and allowed us to estimate the BCE budget of some acidic forest soils. We estimated the overall BCE budget of four sites in this network. Tracer approaches using conservative ions, Na〈sup〉+〈/sup〉 and Cl〈sup〉−〈/sup〉, were calibrated to estimate dry BCE deposition and soil water fluxes. The contribution of atmospheric deposition to the BCE budget was such that potassium was found to be regularly accumulating at all sites at the rate of 0.08 to 0.42 g⋅m〈sup〉−2〈/sup〉⋅y〈sup〉−1〈/sup〉, while calcium was accumulating at a rate of 1.11 g⋅m〈sup〉−2〈/sup〉⋅y〈sup〉−1〈/sup〉 at a central Italy site. For Ca〈sup〉2+〈/sup〉 at the other sites and for magnesium at all sites, the effect of deposition was such that the rate of BCE depletion was significantly reduced. Soil acidification appeared to be a non-active process in the central, lowland and hilly areas of Italy.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Zuzana Ballová, Ladislav Pekárik, Vladimír Píš, Jozef Šibík〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Important influences of burrowing animals on ecosystems are reported from several environments. However, the impact of burrowing on alpine meadows has only been poorly studied. The largest and most widespread burrowing animals living in an alpine region are marmots. We tried to answer the following questions: Do marmots cause structural and compositional changes in alpine plant communities? Do marmots have a significant effect on soil properties? Do vegetation types differ according to their dependency on the functional utilization of the burrow?〈/p〉 〈p〉On a colony scale marmots significantly increased cover of herbs on next-to-burrow mound plots as opposed to on burrow and control plots, while they decreased cover of graminoids, lichens, and litter, which were the highest on sites without marmot activities. Equitability increased gradually in direction from controls, next-to-burrow mound plots to burrow plots. Simultaneously, marmots increased N, Mg and K on next-to-burrow mound plots as opposed to on burrow and control plots.〈/p〉 〈p〉Biopedturbation by marmots contributes to creating the gradient of vegetation between marmot free meadows and disturbed habitats. Tatra marmots encourage settlement of moisture and light-demanding plants with larger requirements for soil depth on their burrow mounds. On next-to-burrow mound plots they support acidophilous vegetation with grazing- and trampling-resistant or grazing-tolerant species. A considerable higher content of P was present directly on the mounds compared to next-to-burrow mound plots.〈/p〉 〈p〉Marmot activities alter soil properties, reduce the dominance of common species and thereby enhance community diversity. Their effects, depending on the volume and nature of their activities, are the strongest on hibernation and maternal burrows and their surroundings. Our results demonstrate the key role of environment-marmot interactions in alpine ecosystems and landscape development.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 CATENA, Volume 182〈/p〉 〈p〉Author(s): Vanessa Solano-Rivera, Josie Geris, Sebastián Granados-Bolaños, Liz Brenes-Cambronero, Guillermo Artavia-Rodríguez, Ricardo Sánchez-Murillo, Christian Birkel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tropical volcanic landscapes are important because of the short timescales (〈 years) over which they transform. Sediment sources, availability and transport can be highly dynamic, but our understanding of these is limited by a lack of data in these complex environments, especially with regards to extreme events. To investigate the responses to extreme rainfall events in particular, we conducted extensive monitoring in a pristine tropical rainforest catchment (3.2 km〈sup〉2〈/sup〉), located in the Volcanic Cordillera of Tilarán, Costa Rica. We established high temporal resolution hydro-meteorological and turbidity monitoring from June 2015 to July 2016. This included a record convective rainfall event in August 2015 which resulted in an estimated 〉50 yr return period flood event. We also surveyed hillslope soils, landslides, and sediments of the river network, to characterize sediments before and after the extreme event. Our results suggested that rainfall events activated surface flow pathways with associated mobilization of material. However, erosion processes were mostly linked to finer material (sand, silt) properties of the soils that developed on more highly weathered bedrock. The single extreme event (return period 〉50 years) had an overriding impact on the general sediment dynamics. Recovery in the form of fine material transport and associated hysteresis took only about three months. We conclude that the combined use of high-temporal resolution monitoring with spatially distributed surveys provided new insights for the initial assessment into the fluvial geomorphology and transport dynamics of steep, volcanic headwater catchments in the humid tropics with potential to establish more complete time scales of land-forming processes. This work can build the foundation for more complete monitoring using radioisotopes as a tool to fingerprint the sediment origin and composition.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0341816219302607-ga1.jpg" width="221" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉