ALBERT

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Sougueh Cheik, Nicolas Bottinelli, Benoit Soudan, Ajay Harit, Ekta Chaudhary, Raman Sukumar, Pascal Jouquet〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the tropics, termites are key litter decomposers and soil bioturbators. Termite foraging activity involves the production of sheetings and galleries that influence the physical, chemical and hydraulic properties of soils. The functional impacts of these biogenic structures and biopores have been acknowledged for a long time in soils dominated by 1:1 minerals. Less is known, however, on their functional impacts in soils dominated by 2:1 minerals, such as vertisol which represent 22% of the land surface in India. Therefore, an experiment was carried out in a vertisol in southern India where elephant (〈em〉Elephas maximus〈/em〉) dung pats (ED) and 〈em〉Lantana camara〈/em〉 twigs (LT) were applied on the ground and protected (+) or not (−) from termite activity. Termite activity was only measured below ED−, showing a clear preference for organic matter derived from elephant dung. Soil sheetings had similar properties to the surrounding topsoil, with the exception of their C content that was reduced. This result raised the question of the origin of the soil used by termites for covering ED. ED− was also associated with the presence of effective macropores up to 5 cm depth and a significant increase in water hydraulic conductivity (12-fold). However, the utilization of the coefficient of linear extensibility showed that these galleries were unstable and most likely short-lived. In conclusion, this study confirmed that the structure of soils dominated by 2:1 minerals is mainly controlled by physical processes (i.e., the shrinking and swelling of soils). This study also stresses the need to better understand the dynamic of termite galleries in soil and to quantify the origin and fate of organic matter in soil sheetings.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Yinli Bi, Kun Wang, Jin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Artificial ecological engineering plays an important role in promoting the restoration of mining subsidence areas. To investigate the effects of field inoculation on soil remediation, field studies were conducted in Shendong Daliuta mining area in Yulin, northwest China. 〈em〉Amorpha fruticose〈/em〉 plants were treated with under five different inoculations, 〈em〉Funneliformis mosseae〈/em〉 (F. m), 〈em〉Rhizophagus intraradices〈/em〉 (R. i), 〈em〉F. mosseae〈/em〉 and 〈em〉R. intraradices〈/em〉 (F. m + R. i), 〈em〉Pantoea〈/em〉 sp. (CA), 〈em〉F. mosseae〈/em〉 and 〈em〉Pantoea〈/em〉 sp. (F. m + CA), as well as no inoculation (CK) as control. The diversity and structure of arbuscular mycorrhizal (AM) fungal communities, glomalin, and soil organic carbon (SOC), available phosphorus, available nitrogen, soil pH were investigated. Based on pyro-sequencing on small subunit ribosomal RNA genes (SSUs), 63 AM fungal operational taxonomic units (OTUs) were identified, which belonged to six genera and two families. F. m + CA inoculation exhibited the highest available phosphorus, the lowest N/P ratio, and higher the ratio between total glomalin-related soil protein (T-GRSP) fractions and soil organic carbon (SOC). Fungal community diversity indices, including Shannon-Wiener, Simpson, and pielou, in F. m inoculation were significantly lower than others, and the phylogenetic index in F. m + CA inoculation was the highest (〈em〉P〈/em〉 〈 0.05). In addition, Permutational multivariate analysis of variance (PerMANOVA) and non-metric multidimensional scaling (NMDS) analyses showed that the distribution of AM fungal communities without F. m inoculation were not significantly different from CK. These results demonstrated that the diversities and structures of AM fungal communities were sensitive indicators for monitoring the environmental changes in subsidence area. Furthermore, structural equation model (SEM) showed that AM fungal diversity had direct effects on T-GSRP. In summary, field inoculation of 〈em〉Amorpha fruticose〈/em〉 plants had a valid effect on soil remediation, and F. m + CA inoculation is the befitting combination for soil restoration in the experimental field.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Jinliang Liu, Vu Ngoc Ha, Zhen Shen, Peng Dang, Hailan Zhu, Fei Zhao, Zhong Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rhizosphere microbial community structure and composition are affected by tree species, soil properties and fine root parameters. In this study, we investigated the changes in rhizosphere soil properties, fine root parameters and rhizosphere microbial community composition following 〈em〉Robinia pseudoacacia〈/em〉 afforestation. Rhizosphere microorganisms were analyzed by high-throughput sequencing of the 16S rRNA gene and the internal transcribed spacer (ITS). Soil available phosphorus (AP) and fine root total phosphorus (RTP) were lower at the 25- and 35-Y sites than at the 5- and 15-Y sites, and fine root parameters could be inferred by soil AP, nitrate nitrogen (NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉) and nitrogen:phosphorus (N:P). Rhizosphere microbial community composition clustered into the 5- and 15-Y group and the 25- and 35-Y group at the operational taxonomic unit (OTU) level. At genus level, 28.57% of the major bacterial genera (relative genera abundances ≥0.1%) and 18.33% of the major fungal genera exhibited significant differences. Rhizosphere soil and fine root properties explained 89.42% and 65.04% of the total variation in the major bacterial genera group, and 84.17% and 62.13% of the total variation in the major fungal genera group at the genus level, respectively. Soil AP and fine root TP are crucial for regulating rhizosphere soil microbial communities. Our results suggest that fine root and soil properties cooperatively affect rhizosphere microbial community composition in the root-soil system following 〈em〉Robinia〈/em〉 afforestation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Shima Shirinbayan, Houshang Khosravi, Mohammad Jafar Malakouti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A large area of Iran is located in arid and semi-arid regions; as a result, drought stress is a major problem for the growth of plants. Therefore, it is very important in crop productivity to increase plant tolerance to drought stress. Plant growth promoting rhizobacteria such as 〈em〉Azotobacter〈/em〉 may enhance plant growth under drought stress conditions by different mechanisms. In this study, a total of 20 〈em〉Azotobacter〈/em〉 strains were isolated and characterized from 77 rhizosphere soil samples collected from semi-arid regions. The strains were screened for the production of siderophore and IAA, solubilization of phosphate and potassium and growth under drought stress in PEG 6000. The strains were identified by 16S rRNA gene sequencing. The efficient strains were tested on the growth of maize (〈em〉Zea mays〈/em〉) under drought stress by using three levels of irrigation, including 80, 60 and 40 percent of field capacity in greenhouse conditions. The laboratory results revealed that Az63, Az69 and Az70 were the most effective strains in terms of phosphate and potassium solubilisation, siderophore producion and maximum growth in PEG 6000. At 40 percent of field capacity, the inoculation increased shoot dry weight, plant height, chlorophyll content, nitrogen, phosphorous and iron concentration compared to the control. Az63 and Az70 increased shoot dry weight significantly at 60 percent of field capacity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Séverine Lopez, Xavier Goux, Antony van der Ent, Peter D. Erskine, Guillaume Echevarria, Magdalena Calusinska, Jean Louis Morel, Emile Benizri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ultramafic soils cover large areas in Indonesia, with over 8000 km〈sup〉2〈/sup〉 on Halmahera Island. Nickel hyperaccumulator plants have evolved on these soils which are suspected to host highly nickel tolerant bacteria in their rhizosphere. To date, research has been limited on the characterization of the genetic diversity of such bacterial communities. The objective of this study was to investigate the genetic diversity of bacterial communities in the rhizosphere of nickel hyperaccumulator plants from Halmahera Island to improve knowledge on the factors that drive bacterial community diversity. We collected 45 rhizosphere soils from 10 woody nickel hyperaccumulator species at 16 sites to highlight the influence of plants, soil chemical parameters and site effects on bacterial diversity, richness and composition. A total of 2,508,874 bacterial 16S rRNA gene sequences were obtained and clustered into 6645 OTUs. In total, 40 phyla were identified with the most dominant phyla being 〈em〉Proteobacteria〈/em〉, 〈em〉Acidobacteria〈/em〉, 〈em〉Actinobacteria〈/em〉 and 〈em〉Chloroflexi〈/em〉. Redundancy analysis between soil chemical characteristics and bacterial phyla relative abundances for the three main species (〈em〉Rinorea〈/em〉 aff. 〈em〉bengalensis〈/em〉, 〈em〉Ficus trachypison〈/em〉 and 〈em〉Trichospermum morotaiense〈/em〉) showed that the main factor driving the bacterial diversity in the rhizosphere of 〈em〉Rinorea〈/em〉 aff. 〈em〉bengalensis〈/em〉 appears to be the plant itself (regardless of the characteristics of the soil), while the impact of soil conditions was important for the two other hyperaccumulator species. This may be explained by the fact that 〈em〉Rinorea〈/em〉 aff. 〈em〉bengalensis〈/em〉 (at least in Halmahera Island) is an obligate nickel hyperaccumulator.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): A.E.S. Cerqueira, T.H. Silva, A.C.S. Nunes, D.D. Nunes, L.C. Lobato, T.G.R. Veloso, S.O. De Paula, M.C.M. Kasuya, C.C. Silva〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The advance of livestock towards the hydrographic basin of Mutum-Paraná River, in the state of Rondônia contributes to the conversion of the amazon forest to pasture. This process can decrease the plant diversity, contributing to loss of endemic microorganisms and natural enemies leading to the replacement of native biota by non-native and generalist species. Thereby, we hypothesized that this conversion changes fungal composition, reduce fungal alpha diversity and community dissimilarity and increase the incidence of potential phytopathogenic genera at pasture soils compared to forest. Soil of 10 sampling points from forest and 10 from pasture were collected at the Mutum-Paraná River basin. Via ITS amplicon sequencing of the total soil DNA, differences in composition and in the taxonomic diversity between the two environments were addressed. The phylum Ascomycota predominated in both forest and pasture. Basidiomycota presented lower percent in both, but was higher in pastures. Zygomycota and Glomeromycota presented opposite tendencies, the first being predominately present in forest and the second only present in pasture with low incidence. The fungal diversity was higher in pasture soils, contrasting our hypothesis. There were also significant correlations between soil physicochemical properties and fungal community. The reduction of the dissimilarity in pasture was confirmed and this signalized for a biotic homogenization. In addition, higher incidence of potential phytopathogenic fungi was observed in pasture. These results contribute to a better understanding of how fungal communities are driven by forest-to-pasture conversion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Ryan Orr, Paul N. Nelson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Production of many crops, including bananas, is threatened worldwide by the spread of pathogenic strains of 〈em〉Fusarium oxysporum〈/em〉, the causal agent of Fusarium wilt. Severity of the disease is related to soil biotic and abiotic attributes, which influence the plant, the pathogen and the other soil organisms. Across a variety of crops, soil temperature, redox potential, and extractable iron and manganese contents are generally positively correlated with disease severity, whereas pH, nitrate:ammonium ratio, organic matter content and extractable calcium, zinc, silicon, potassium, phosphorus and boron contents are negatively correlated, but less consensus exists for bananas. There are numerous incompletely understood interactions between soil abiotic attributes and disease severity, including those between pH- and redox-controlled micronutrient availability, buffering by organic matter and clay, and effects of nutrients on plant defence mechanisms. Though not all soil attributes can be managed, pH, organic matter content and availability of nutrients show promise for manipulation to reduce disease severity and mitigate risk.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): H. Huot, J. Cortet, F. Watteau, V. Milano, J. Nahmani, C. Sirguey, C. Schwartz, J.L. Morel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Forest ecosystems can spontaneously establish themselves on former industrial sites contaminated by metals. The sustainable management of these sites by natural attenuation requires a better understanding of the relationships between soil biodiversity, metals and soil functioning in such ecosystems. In this context, a forest ecosystem growing on iron industry by-products containing potentially toxic metals as major elements was studied using a multiproxy approach including chemical soil properties, microstructure, meso- and macro-fauna. Fauna communities in the topsoil were characterized by a high abundance and taxonomic diversity, but also by an unusual predominance of epigeic and detritivorous species. Fauna community structures were partly explained by the presence not only of heavy metals (Zn, Cd), but also Fe and Mn, dominant metals in iron industry by-products. The uncommon structure of macrofauna communities could have effects on the soil functioning, such as limiting the incorporation and mixing of organic matter into the soil. Mesofauna communities contributed to the metal redistribution in the soil by integrating metals into organo-mineral associations. In terms of management, this study showed the feasibility of using natural attenuation to manage sites with high metal contents but low metal availability and favorable conditions for plant growth. However, the influence of soil biota on metal mobility and soil functioning needs to be further investigated in order to assess the sustainability of such management.〈/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-S0929139318300702-ga1.jpg" width="416" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Violeta Matus-Acuña, Gustavo Caballero-Flores, Blanca J. Reyes-Hernandez, Esperanza Martínez-Romero〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we analyzed the nematode-bacteria-plant interaction by using bacteriovorus nematodes isolated from maize rhizosphere and plant growth promoting rhizobacteria to evaluate their effect on plant growth and root development of maize and 〈em〉Arabidopsis thaliana〈/em〉. Two bacterial feeding nematodes, identified as 〈em〉Oscheius tipulae〈/em〉 and 〈em〉Mesorhabditis〈/em〉 sp., displayed distinct attraction patterns for seven rhizosphere bacteria with a strong bias towards 〈em〉Rhizobium〈/em〉 strains. We tested the effect of these two nematodes on both plant growth and root morphology using native 〈em〉Zea mays〈/em〉 and found that the co-inoculation of 〈em〉Rhizobium phaseoli〈/em〉 Ch24-10, a plant growth promoter, and maize rhizosphere nematodes, increased dry weight of corn plants compared to plants treated only with bacteria or the nematode. Additionally, we found that the nematodes reduced the weight and length of the primary root and increased the number of emerging lateral roots. We further analyzed the effect of nematodes and bacteria using the model plant 〈em〉A. thaliana〈/em〉 and observed similar effects on roots as those found in native corn. Nematodes reduced the primary root growth and increased the number of emerging lateral roots. The model nematode 〈em〉Caenorhabditis elegans〈/em〉 N2 alone had no effect on 〈em〉A. thaliana〈/em〉 plants, it became capable of affecting root morphology when fed with 〈em〉Acinetobacter pittii,〈/em〉 which was originally isolated from the maize rhizosphere nematodes. Our results suggest a synergistic effect of nematodes and their associated bacteria both in plant development and root morphology, highlighting the importance of nematode-bacteria interactions in shaping plant growth and root morphology. A model of nematodes as Trojan horses carrying bacteria is proposed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Dayana da Silva Correia, Samuel Ribeiro Passos, Diogo Neves Proença, Paula Vasconcelos Morais, Gustavo Ribeiro Xavier, Maria Elizabeth Fernandes Correia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interactions between saprophagous invertebrates and microbes are essential for the maintenance and functioning of soil ecosystems, as they directly affect the degradation of organic matter and the nutrient cycle. The intestinal tract of invertebrates is inhabited by a diversity of microbes, and it is closely associated with the food ingested. The aim of this work was to evaluate the profile of prokaryotes associated with the intestinal tract of three invertebrate species. The species of invertebrates 〈em〉Trigoniulus corallinus〈/em〉 was collected and incubated in the experiment, after 5 days of incubation we observed the uninduced colonization of two invertebrate species 〈em〉Cubaris murina〈/em〉 and 〈em〉Pycnoscelus surinamensis〈/em〉. Therefore, the three species were evaluated in the same way, after 60 days of incubation. The diet supplied comprised different vegetal residues, with distinct carbon/nitrogen compositions. Six treatments were evaluated. After 60 days, five individuals of each species were randomly selected, by removing the posterior third of the intestinal tract. These specimens were next subjected to DNA extraction. The PCR/DGGE analysis was carried out using the 16S rDNA, for the domain Bacteria and the phylum Actinobacteria. DGGE bands were cloned and sequenced using the Bacterial domain. In multivariate analyzes, individuals of the same species after 60 days of incubation, were strongly grouped. These results may be in accordance with the environmental criteria of the host itself, stage of development, phylogeny and diet. Thus, the investigation of the intestinal microbiota, provides relationships between invertebrates and their intestinal bacterial communities. In view of this information, we used the technique of sequencing cloned DGGE bands to quantify the diversity of microorganisms present in the intestinal tract of the studied invertebrates. The phylum Firmicutes, Bacteroidetes, and Proteobacteria were identified by sequencing the cloned bands; Proteobacteria presented the highest number of genera, comprising 〈em〉Enterobacter〈/em〉, 〈em〉Buttiauxella〈/em〉, 〈em〉Serratia〈/em〉, 〈em〉Kluyvera〈/em〉, and 〈em〉Pantoea〈/em〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Hua Xiao, Richard R. Rodrigues, Merideth Bonierbale, Richard Veilleux, Mark Williams〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Iron (Fe) is a crucial nutrient for plant growth (e.g. chlorophyll production), and though it is one of the most abundant elements in soil, very low bioavailability can limit plant growth. Studies indicate that many soil bacteria and fungi (e.g. mycorrhizal) play a role in Fe nutrient cycling and plant production, but the evidence for fungal support of plant growth is overwhelmingly correlative and in need of experimental corroboration. An Andean native potato landrace was grown in a greenhouse under Fe limitation and using three levels (Low, Medium, High) of foliar fertilization (FeEDDHA). Application occurred at 45, 60 and 70 days of growth corresponding to periods where Fe limitation is expected to be greatest. The rhizosphere soils were sampled at the flowering stage (80 days). Soil bacterial and fungal communities were examined using high-throughput sequencing of 16S and ITS regions of ribosomal RNA gene, respectively, followed by analysis using Quantitative Insights Into Microbial Ecology (QIIME v1.8). Multivariate data analyses showed that Fe fertilization of leaves significantly (〈em〉p〈/em〉 〈 0.05) influenced the beta diversity of fungi but not bacterial communities in the rhizosphere. Using our novel approach, it was expected and confirmed that fungal communities would shift and mycorrhizal genera (〈em〉Glomus〈/em〉) would be altered, however, the degree to which community change was observed was more than expected. 〈em〉Glomeromycota〈/em〉 (∼16.3%) related to the family 〈em〉Gigasporaceae〈/em〉 accounted for 2.8% of OTU and were 2–3 times greater in the rhizosphere of high relative to medium and low Fe conditions. Overall, the results indicate that foliar addition of Fe influences plant Fe and resonates into the root system to affect rhizosphere fungal communities. Potato Fe status thus appears to impact potato root-fungal interactions potentially mediated through mycorrhizal fungi.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Silvana Gomes dos Santos, Valfredo Almeida Chaves, Flaviane da Silva Ribeiro, Gabriela Cavalcanti Alves, Veronica Massena Reis〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Renovation of Brazilian sugarcane plantations using the pre-sprouted seedling technique (PSS) was undertaken to increase sanitation and productivity while reducing the cost of sugarcane planting. The objective of this study was to evaluate growth, nutrient acquisition, and contribution of biological nitrogen fixation (BNF) in two sugarcane cultivars RB867515 and IACSP95-5000, inoculated with five strains/species of diazotrophic bacteria, applied together and individually, for 60 days during growth. The cultivars were grown in a greenhouse in boxes filled with a sterile substrate followed by growth in tubes filled with a commercial substrate in the second phase; finally the plants were transferred to pots containing soil enriched with 〈sup〉15〈/sup〉N and grown outdoors. The treatments used were control (no inoculation); mixed inoculation with the five strains, 〈em〉Gluconacetobacter diazotrophicus〈/em〉 (PAL5〈sup〉T〈/sup〉), 〈em〉Herbaspirillum rubrisubalbicans〈/em〉 (HCC103), 〈em〉Herbaspirillum seropedicae〈/em〉 (HRC54), 〈em〉Nitrospirillum amazonense〈/em〉 (CBAmC) and 〈em〉Paraburkholderia tropica〈/em〉 (PPe4〈sup〉T〈/sup〉); and individual inoculation with each strain. Increases of up to 50% in the root dry mass was observed following mixed inoculation of the seedlings in the germination phase, with a significant increase in root initiation, volume, and area, especially of the fine roots. Inoculation of seedlings of both cultivars led to increased biomass in tubes of non-sterile substrate. In soil, a higher nitrogen accumulation was also observed in the cvar. IACSP95-5000 in all treatments except plants inoculated with 〈em〉N. amazonense〈/em〉. For the cvar. RB867515 shoots, the opposite was observed were the highest N accumulation was observed for 〈em〉N. amazonense〈/em〉, 〈em〉H. seropedicae〈/em〉 followed by the mixture. In this experiment using soil labelled with 〈sup〉15〈/sup〉N there was a response on N uptake caused by all bacteria used in one cvar but only by 2 of the 5 strains in other cvar. Using the 〈sup〉15〈/sup〉N enrichment of the plants the results showed that the control and inoculated plants all derived 60–70% of N from the atmosphere, and inoculation had no effect on BNF contribution. For P and K levels, RB867515 showed no effect of inoculation, but the other cvar. did respond to inoculation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Pallieter De Smedt, Safaa Wasof, Tom Van de Weghe, Martin Hermy, Dries Bonte, Kris Verheyen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Forests are structurally rich ecosystems with strong spatial variation in microclimate. Local temperature and soil moisture are important drivers of leaf litter breakdown, a key ecosystem process vital for forest functioning. Additionally, detritivore species composition and activity are equally dependent on microclimate, rendering changes in microclimate key to understand leaf litter breakdown. We investigated the interaction between microclimatic variables (i.e. temperature and moisture) and different combinations of macro-detritivores (a drought sensitive i.e. 〈em〉Oniscus asellus〈/em〉 vs. a drought tolerant species i.e. 〈em〉Glomeris marginata〈/em〉) on litter breakdown of easily decomposable (high quality) 〈em〉Acer〈/em〉 litter and decomposition resistant (low quality) 〈em〉Quercus〈/em〉 litter in a full factorial microcosm field experiment in a temperate forest in Belgium. We hypothesize litter breakdown to be faster for high quality litter and macro-detritivore biomass and dependent on macro-detritivore identity, mediated by forest microclimate e.g. faster with higher soil moisture and warmer temperatures.〈/p〉 〈p〉We found high quality litter breakdown to be reduced by decreasing moisture availability, while it was not affected by temperature. There was no effect of moisture and temperature on litter breakdown of low quality litter. The effect of detritivore biomass on the breakdown of 〈em〉Quercus〈/em〉 litter depended on detritivore identity: elevated millipede biomass increased 〈em〉Quercus〈/em〉 litter breakdown, which was not the case for woodlice. There was a positive effect of macro-detritivore biomass but no effect of macro-detritivore identity on leaf litter breakdown of high quality litter. In addition, the relative consumption rates were equal between the drought sensitive (woodlouse) and the drought tolerant (millipede) species for high quality litter, but different for low quality litter. The woodlouse species was more efficient in the breakdown of low quality litter compared to our tested millipede species. Relative consumption rate was not influenced by the moisture or temperature treatments. Combining both detritivore taxa in a single microcosm had additive (non-synergistic) effects on litter breakdown, indicating that they are not complementary in their resource use. We conclude that mainly differences in moisture availability in forest ecosystems are important for litter breakdown and that detritivore identity is critical for the breakdown of especially low quality litter.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Peilei Hu, Shujuan Liu, Yingying Ye, Wei Zhang, Xunyang He, Yirong Su, Kelin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vegetation restoration following agricultural abandonment is an effective method for soil organic carbon (SOC) sequestration. However, SOC dynamics during post-agriculture succession in different soil layers, and its regulation by soil nitrogen (N), are not well understood. We investigated SOC and soil N dynamics during post-agriculture succession at soil depths of 0–10, 10–20, 20–30, and 30–50 cm in a subtropical karst area in southwest China. The succession sequence included grassland (∼9 years), shrubland (∼25 years), secondary forest (∼52 years), and primary forest, with cropland as a reference. In the 0–50 cm soil profile, the SOC and soil N stocks will recover to the primary forest level in ∼74 years at a rate of 112.35 g C m〈sup〉−2〈/sup〉 yr〈sup〉−1〈/sup〉 and in ∼100 years at a rate of 12.07 g N m〈sup〉−2〈/sup〉 yr〈sup〉−1〈/sup〉, respectively. The accumulation rate of SOC and soil N was higher in the topsoil (0–20 cm) than in the subsoil (20–50 cm). The estimated time for SOC stock to recover to the primary forest level in topsoil and subsoil was similar (72 and 76 years, respectively), whereas that for soil N stock require more time in topsoil than in subsoil (106 and 89 years, respectively). The higher rate of relative N stock change than that of SOC suggests that progressive N limitation does not occur in the long term following agricultural abandonment. Our results highlight the importance of soil depth and soil N in determining SOC change for secondary succession. Furthermore, the results suggest that, compared to that of previous studies, which considered only surface soil in the karst regions of southwest China, the recovery period of C and N in soil profile may be longer than that assumed previously.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Małgorzata P. Oksińska, Elżbieta G. Magnucka, Krzysztof Lejcuś, Anna Jakubiak-Marcinkowska, Sylwia Ronka, Andrzej W. Trochimczuk, Stanisław J. Pietr〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The colonization and biodegradation of the superabsorbent polymer component of water absorbing geocomposite by microorganisms occurring in the soil were investigated using a pot experiment. The polymer used in this study was technical cross-linked potassium polyacrylate (tKPA). It was placed inside a plastic skeleton structure covered with a polyester fabric sheath and incubated in non-sterile Haplic Luvisol soil sown with grass for nine months. After this time, we noticed a 77.88% reduction of 4.25 g of the tKPA initial dry mass. The highest number of soil microbes that colonized and utilized tKPA as the sole carbon and energy source was found after the first month of incubation. It ranged from 4.02 log〈sub〉10〈/sub〉 CFU g〈sup〉−1〈/sup〉 of water absorbed by tKPA for fungi and protists to 6.99 log〈sub〉10〈/sub〉 CFU for bacteria; during the next eight months, the number decreased to 3.05 and 5.63 log〈sub〉10〈/sub〉 CFU, respectively.〈/p〉 〈p〉〈em〉Bacillus megaterium〈/em〉 isolate 37SBG and the 〈em〉Acremonium sclerotigenum – Acremonium egyptiacum〈/em〉 complex isolate 25SFG shown to possess the ability to degrade tKPA were selected among the microorganisms that colonized the superabsorbent polymer. After 60 days of incubation of these microorganisms in mineral media supplemented with tKPA as the sole nutrient source, 280.50 mg of the initial polymer dry mass declined by 30.28% and 20.50% for 37SBG and 25SFG, respectively. In addition, after 30 days of growth in a medium mimicking the composition of grass root exudates that was additionally enriched with ultra pure cross-linked potassium polyacrylate (upKPA), 17.21% of the 267 mg initial dry mass of upKPA was degraded by 〈em〉B. megaterium〈/em〉 37SBG. Enzymatic activity similar to lignin peroxidase appears to be connected with this process.〈/p〉 〈p〉The tKPA geocomposite component was also effectively colonized by phytopathogens from the genus 〈em〉Phytophthora〈/em〉. Their numbers ranged from 0.70 to 2.26 log〈sub〉10〈/sub〉 CFU g〈sup〉−1〈/sup〉 of water absorbed by tKPA after 5 and 12 months, respectively, of the geocomposite incubation in the soil. In addition, some colonized tKPA microorganisms were able to limit the multiplication of the pathogen. The mycelial growth of 〈em〉Phytophthora cactorum〈/em〉 and 〈em〉Rhizoctonia solani〈/em〉 was inhibited in the presence of the 〈em〉A. sclerotigenum–A. egyptiacum〈/em〉 complex isolate 25SFG.〈/p〉 〈p〉We concluded that the colonization of tKPA by both microbes with the ability to biodegrade it and phytopathogenic oomycetes could limit the soil application of geocomposite as a plant growth support. The biodegradation of tKPA by soil bacteria, fungi, and protists seems to also be important for the reduction of the amount of polymer residues deposited in the soil. In addition, this study expands our knowledge about antagonistic interactions between polymer degrading microbes and soil-borne pathogens.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Caroline Krug Vieira, Luiz Gustavo dos Anjos Borges, Leticia Marconatto, Adriana Giongo, Sidney Luiz Stürmer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Cerrado domain is composed of different phytophysiognomies and considered a 〈em〉hot spot〈/em〉 of global diversity. However, few studies have assessed the soil microbiome of this domain using metabarcoding approach. This study aimed to determine the soil microbiome in a mining site under revegetation and compare with communities of pristine ecosystems. Soil samples were collected in the dry and rainy seasons in an iron-mining site under revegetation (RA), semi-decidual forest (FL), 〈em〉canga〈/em〉 (NG) and Cerrado 〈em〉stricto sensu〈/em〉 (CE). Soil community was accessed by the amplification of the 16S and 18S ribosomal gene fragments using high-throughput sequencing. The prokaryotic operational taxonomic units (OTUs) were assigned to 18 phyla, 48 classes, 73 orders, 123 families and 168 genera. Acidobacteria and Proteobacteria were the most abundant phylum for FL, CE and RA while Actinobacteria and Acidobacteria were dominant in NG. Relative abundance of families within each phylum varied mainly among sites, but not seasons. For Eukarya, OTUs were assigned to 15 phyla, 35 classes, 94 orders, 168 families and 247 genera. Opisthokonta, SAR (Stramenopiles, Alveolates, and Rhizaria), and Archaeplastida were the most abundant groups for all phytophysiognomies and Fungi accounted for 51–71% of total sequences. Principal coordinate analysis indicates that soil community composition was not influenced by season within each site. We concluded that soil microbiome was dissimilar among sites at the family and genus level but sites shared the same dominant phyla, and that differentiation of soil microbiome was driven mainly by plant community composition.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Graham S. Frank, Cindy H. Nakatsu, Michael A. Jenkins〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Invasive woody plant species are a threat to biodiversity and ecosystem function in forests of the eastern U.S., due in part to their effects on soil properties and nutrient cycling. Controlling invasive shrubs can benefit the ecosystem at multiple scales, but these species tend to resprout when cut, and post-cutting flushes of root exudates have been linked to accelerated decomposition of soil organic matter (SOM), a rhizosphere priming effect. We removed the invasive shrub 〈em〉Lonicera maackii〈/em〉 (Rupr.) Herder (Amur honeysuckle) from forested sites in central Indiana, USA, using cut-stump and forestry mulching head treatments. For two growing seasons after the initial removal treatments, we compared the soil chemistry and microbial community function of bulk and honeysuckle rhizosphere soils in shrub removal areas to those in invaded reference areas. Microbial activity measured using multiple substrate induced respiration (MSIR) in bulk soils was generally lower in removal areas than reference areas the first year, coinciding with relatively elevated responses in the rhizosphere soils of resprouting shrubs. Elevated SOM and organic C in rhizosphere soils of resprouting shrubs suggested a flush of rhizodeposits from cutting and regrowth. However, bulk soil chemistry responses to shrub removal did not show any evidence of a rhizosphere priming effect, but instead reflected the reduced effects of honeysuckle on throughfall precipitation chemistry—higher ammonium and lower magnesium. Nonetheless, changes in bulk soil chemistry between years were driven by the chemical characteristics of rhizosphere soil associated with resprouting honeysuckle. This study is the first to document the potential for invasive shrub control to affect soil properties through rhizodeposition by the target species.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Fabienne Legrand, Adeline Picot, José Francisco Cobo-Díaz, Matthieu Carof, Wen Chen, Gaétan Le Floch〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Agricultural soil microbial communities are largely impacted by agronomic practices, soil physicochemical properties and climatic conditions. To understand how these factors induce changes in fungal and bacterial communities in soil, we used a metabarcoding approach to profile the microbial communities of 31 agricultural wheat fields with maize as previous crop, representative of usual crop rotation in Brittany, France. Our results clearly highlighted the importance of tillage for both bacteria and fungi, with species richness and evenness significantly higher in fields under minimum tillage practices than in fields under conventional tillage, despite that the core microbiota was similar between fields under these two practices. The functional diversity of the bacterial communities, predicted using FAPROTAX, was also significantly higher in fields under minimum tillage notably that involved in nitrogen cycling (denitrification, respiration). We also observed that animal manure increased bacterial richness and evenness compared to chemical fertilization only. Interestingly, fungal diversity was less sensitive to disturbance than bacterial communities. We also identified taxa groups as potential bioindicators of a specific agronomic practice, such as the strong association between animal manure application and 〈em〉Hydrogenophaga〈/em〉, 〈em〉Mycoplana〈/em〉 and 〈em〉Sphingopyxis〈/em〉, as well as the enrichment of oligotrophic 〈em〉Acidobacteria〈/em〉 under conventional tillage.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Vasileios A. Tzanakakis, Antonios Apostolakis, Nikolaos P. Nikolaidis, Nikolaos V. Paranychianakis〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Strains of ammonia oxidizing archaea (AOA) can utilize urea under limited conditions of ammonia in terrestrial environments. In this work, we investigate whether this mechanism operates more widely, including soils with non-limiting conditions of ammonia. To test this hypothesis, pots filled with a soil of basic pH (8.3) were supplied with two rates of N (25 and 50 μg N/g dry soil) in the form of urea and ammonium applied at seven consecutive doses every 2 days. The findings of the study revealed a strong increase in the abundance of ammonia oxidizing bacteria (AOB) at both application rates, independently of N source. By contrast, AOA did not respond to N additions. These findings indicate that urea availability does not offer an advantage on the growth and activity of AOA over the AOB under non-limiting conditions of N. However, a slight increase in AOA abundance following substrate utilization provided support for a link between AOA growth and mineralization of soil organic matter.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Mengli Zhao, Jun Yuan, Ruifu Zhang, Menghui Dong, Xuhui Deng, Chengzhi Zhu, Rong Li, Qirong Shen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Non-ribosomal peptides (NRPs) are one of the largest groups of natural microbial secondary metabolites, which include peptides such as the antibiotics vancomycin and gramicidin, as well as lipopeptides (surfactin, iturin A and bacillomycin). In this study, banana Fusarium wilt disease suppressive and conducive soils were chosen to investigate the role of microbes that harbor the NRPS gene in disease suppression based on the 454-pyrosequencing platform and real-time PCR technique. The results showed that higher abundances and diversity of microbes that harbor the NRPS gene were observed in the suppressive soil samples than in the conducive soil. According to the results of the DNA sequences blastx of NRPS, the main microbial taxa harboring the NRPS gene were identified, and 〈em〉Pseudomonas〈/em〉 in Proteobacteria and 〈em〉Streptomyces〈/em〉 in Actinobacteria might be remarkably related to Fusarium wilt disease suppression. Furthermore, the Mantel test showed that compared with bacteria community and chemical properties, the microbial community harboring the NRPS gene had a more significant impact on the disease incidences of Fusarium wilt. This study provided non-specific relationships between groups of microbes harboring NRPS genes and Fusarium wilt disease suppression suggesting potential interaction based on correlation evidence, and pointed out a potential mechanism of suppressive soil.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Annum Sattar, Muhammad Naveed, Mohsin Ali, Zahir A. Zahir, Sajid M. Nadeem, M. Yaseen, Vijay Singh Meena, Muhammad Farooq, Renu Singh, Mahfuz Rahman, Har Narayan Meena〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Potassium is a major essential plant nutrient that plays a pivotal role in plant physiological and metabolic processes, and provides resistance against biotic and abiotic stresses. In order to feed an ever increasing world population, cultivation of high yielding varieties in an intensive production system during the last few decades caused depletion soil fertility status, especially potassium (K). As 90–98% K reserves in soil system are non-exchangeable mineral sources, efficient rhizospheric microbes (ERMs) are needed to effectively dissolve this mineral and make it available to plants. A diverse group of ERMs such as rhizobacteria (〈em〉Bacillus edaphicus〈/em〉, 〈em〉B. mucilaginosus〈/em〉, 〈em〉Acidothiobacillus ferrooxidans〈/em〉, 〈em〉B. circulans〈/em〉, 〈em〉Paenibacillus〈/em〉 sp.), fungal strains (〈em〉Aspergillus terreus〈/em〉 and 〈em〉Aspergillus〈/em〉 sp.) and nitrogen fixing rhizobacteria (NFR) is involved in K mineral (orthoclase, muscovite, feldspar, biotite, mica, illite) solubilization. Mechanisms utilized by microbes for K dissolution are organic acid production, lowering soil pH, acidolysis, chelation, exchange reactions and complexation. These ERMs also contribute to other beneficial effects such as production of growth hormones, nitrogen (N) fixation, phosphorus (P) dissolution, enlargement of root system and antibiotic production. More specifically, potassium solubilizing microbes (KSMs) are being commercialized in the form of biofertilizer and inoculum to alleviate constraints of chemical fertilizers. This is an ecofriendly approach towards sustainable food production systems in many countries of the world. This report updates our current knowledge and potential for developing microbial based products〈strong〉.〈/strong〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Parvaze Ahmad Wani, Nuhu Abubakar Hussaini, Said Hussaini Garba, Shazia Wahid, Faleye Kafayat Damilola, Adebowale Abiodun Adeola, Idris Adegbite Wasiu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Release of industrial waste into agricultural land affects its productivity. Among different remediation strategies (physico-chemical vs. biological), biological strategy, e.g. symbiotic association of microbes and plants, is among the most efficient ones to control/remediate pollution in agricultural land. The present study was performed to assess potential role of bacterial strain B6 for detoxification of Cr (VI) into Cr (III) and ameliorate toxicity of chromium (VI) in cowpea plants. Bacterial strain B6 completely reduced Cr (VI) at pH 6–7, 25–30 °C and 200–300 µg/ml Cr (VI). Bacterial strain B6 reduced Cr (VI) into Cr (III) [31.5 µg/ml of Cr (III) in supernatant and 71.3 µg/ml in debris]. Chromium reductase enzyme produced by strain B6 completely reduced Cr (VI) to Cr (III), compared to cell debris which did not show Cr (VI) reduction. PCR amplification revealed presence of Cr (VI) reductase gene (Chr) in 〈em〉Bacillus〈/em〉 species B6 showing a fragment of around 300 bp. MDA and antioxidant levels showed an increasing trend with increase in dose rate of Cr (VI). Bacterial inoculation in general, showed maximum photosynthetic pigments and enhanced antioxidants which together optimized growth of cowpea when grown in pot soils amended with different dose rates of Cr (VI). Improvement in cowpea growth, photosynthetic pigments and antioxidants were due to complete reduction of Cr (VI) to Cr (III) by 〈em〉Bacillus〈/em〉 species B6 after 20 days of growth of cowpea. Chromium (VI) reduction and antioxidant expression under 〈em〉in vitro〈/em〉 and 〈em〉in vivo〈/em〉 conditions were responsible for overall growth of cowpea.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Hongying Yu, Quanhui Ma, Xiaodi Liu, Zhenzhu Xu, Guangsheng Zhou, Yaohui Shi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Climatic warming abnormally alters the structure and function of terrestrial ecosystems. It is vital to understand the response of belowground biota such as soil microbial communities to warming regimes, especially in native arid areas. The present 〈em〉in situ〈/em〉 experiment was established to determine the effects of climatic warming regimes on soil microbe communities and the relationships between soil microbial groups and soil physicochemical features in a desert grassland ecosystem. Two warming regimes—long-term moderate warming (T1) and short-term acute warming (T2)—were established to simulate different climatic change scenarios. Soil from each plot was collected in 2014 at the late stage of the experiment, and phospholipid fatty acid (PLFA) profiling analysis was performed to assess the composition of the soil microbial communities. It was found that warming induced a severe water deficit stress. The T2 warming regime significantly increased the ratio of bacteria to fungi (B/F), and the ratio of Gram-positive to Gram-negative bacteria (GP/GN) in August. Belowground biomass (BGB) and soil organic carbon (SOC) were significantly correlated with all of the soil microbial groups in August. The changes in B/F and GP/GN ratios might indirectly induce changes in microbial structure. It was concluded that alterations in the structure of soil microbial communities may strongly depend on growing seasons and that soil nutrient status might have a profound impact on soil microbial communities’ responses to climatic warming.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Rebecca L. Mau, Paul Dijkstra, Egbert Schwartz, Benjamin J. Koch, Bruce A. Hungate〈/p〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Shaojun Wang, Jihang Li, Zhe Zhang, Minkun Chen, Shaohui Li, Run Cao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The research about the effect of ants on soils is generally focused on the aboveground-nesting ant species in temperate soils. Little is known about the potential of belowground nesting ants in regulating soil properties in tropical forests. In this study, three belowground-nesting 〈em〉Pheidole〈/em〉 ant species with different feeding habits were surveyed to explore the nesting effects on microbial carbon and physicochemical properties in tropical forest soils. We found that 〈em〉Pheidole〈/em〉 ants with high-density nests can induce a pronounced effect on the concentration and vertical variability of microbial carbon and physicochemical properties in soils. 〈em〉Pheidole capellini〈/em〉 as a honeydew harvester elevated the levels of soil microbial carbon, soil temperature, total organic carbon, readily oxidizable carbon, and total nitrogen and NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉, but decreased soil bulk density. Whereas, the highest increase in soil moisture and NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 was observed in the nests of 〈em〉P〈/em〉. 〈em〉noda〈/em〉 ants (seed predator), and the greatest decrease of dissolved organic nitrogen was in the nests of 〈em〉P〈/em〉. 〈em〉spathifera〈/em〉 ants (scavenger). 〈em〉Pheidole capellini〈/em〉 ants inputted more materials into the nests, thus they had the greatest modification on the concentration and vertical change in soil properties. We conclude that 〈em〉Pheidole〈/em〉 ant species differ in the direction and power of their effect on soil heterogeneity and soil fertility, which may be mainly attributed to different feeding strategies in the tropical forests.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Holly J. Stover, M. Anne Naeth, Katja Boldt-Burisch〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Native grasslands are endangered by non-native plant invasion worldwide, including foothills fescue grasslands in North America. Large populations of non-native plant species have established in these disturbed fescue grasslands, forming dense monocultures and spreading into undisturbed areas. Soil disturbance and plant invasion can alter the arbuscular mycorrhizal fungi (AMF) community, an important symbiotic partner of most land plants, which could negatively affect native plant reestablishment. The objective of this study was to assess whether AMF communities on a fescue grassland shifted in response to disturbances by landfill storage and gravel quarrying and with invasion of non-native plant species relative to undisturbed grassland.〈/p〉 〈p〉Soil and root-AMF samples were procured from disturbed and undisturbed areas at three sites. Plant canopy cover and species richness were assessed. Soils were analyzed for pH; electrical conductivity; total nitrogen, carbon and phosphorus; and available nutrients. For relative AMF taxa abundance assessment, NS31 and AMF specific primer AML2 were used to amplify a central fragment of the V3 and V4 region of the 18S rRNA gene. AMF were characterized using 454 pyrosequencing and multiplexed barcoded samples amplified from genomic DNA isolated from roots.〈/p〉 〈p〉There were 92 AMF, including 15 potentially novel taxa detected. AMF communities in disturbed and undisturbed sampling locations were distinct except for one site, and indicator AMF virtual taxa (VT) for undisturbed grassland and disturbed sites were identified. AMF richness was higher in undisturbed (72 VT) than disturbed (64 VT) sites and AMF richness was positively correlated with plant species richness, diversity and native plant cover, and negatively correlated with non-native plant cover. There were 43 AMF VT on undisturbed and disturbed sites, 62% with higher relative abundance on disturbed sites. Site disturbance shifted AMF communities relative to undisturbed native fescue grassland; thus restoration success with native plants might be highly dependent on reintroducing native AMF.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Melanie Glenn〈/p〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Giovanna Visioli, Anna Maria Sanangelantoni, Federica D. Conti, Beatrice Bonati, Ciro Gardi, Cristina Menta〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study we analysed the diversity of vascular plants, soil microorganisms and microarthropods on two serpentine outcrops in the Northern Apennines (Italy). The soils of the two sites are at different stages of evolution, as shown by soil depth and soil organic matter (SOM) content: the first site is a serpentine grassland clearing within sub-montane vegetation, while the second is a serpentinite scree rich in specialised flora only, including rare hyperaccumulator plant species such as 〈em〉Noccaea caerulescens〈/em〉 and 〈em〉Alyssum bertolonii〈/em〉. The aboveground biodiversity was analysed via floristic relevés. The bacterial diversity was estimated through 16S rDNA profiling of the Ni hyperaccumulator 〈em〉N. caerulescens〈/em〉 at the rhizosphere level〈em〉,〈/em〉 which thrives in both sites. Microarthropod communities were characterized by extracting and identifying organisms from the soil. The number of individuals per taxon, Acari/Collembola ratio, biodiversity indices and QBS-ar index were calculated. The two sites showed a clear difference as regards plant community: only three plant species were present in both sites〈em〉,〈/em〉 namely 〈em〉Euphorbia cyparissias〈/em〉, belonging to Euphorbiaceae, 〈em〉Galium〈/em〉 spp., belonging to Rubiaceae, and 〈em〉N. caerulescens〈/em〉, belonging to Brassicaeae. Belowground diversity was positively correlated with vegetation cover and SOM content. In particular, among the bacteria colonising the rhizosphere of 〈em〉N. caerulescens〈/em〉 (present in both sites), Actinobacteria, which exhibit 〈em〉K-strategist〈/em〉 attributes and are more successful in resource-limited, crowded environments, appeared to be more abundant in the site with lower SOM and higher content of Ni. Bacterioidetes, which are specialised in degradation of cellulose, chitin and plant detritus, were instead more abundant in the site with higher SOM. As for soil microarthropod communities, the site with higher concentration and bioavailability of heavy metals and lower SOM showed poorer and less structured community. In conclusion, the data observed with plant, microbial and microarhropod communities identify different micro-habitats, in spite of proximal geographical position and the common metal-rich substrate.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Filipa Reis, Eduardo Nascimento, Helena Castro, Cristina Canhoto, Ana Lúcia Gonçalves, Sara Simões, Pablo García-Palacios, Rubén Milla, José Paulo Sousa, Pedro Martins da Silva〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The detritivore woodlouse 〈em〉Porcellio dilatatus〈/em〉 was selected to test the effects of home-field advantage and land management on the isopod feeding preferences and ingestion rates. Woodlice specimens and plant litter from two neighbouring farms were used in “cafeteria” experiments. The farms are cork-oak agro-forests with a similar litter matrix but different land-use history and current management (organic vs. conventional farms). The plant litter species selected were 〈em〉Quercus suber〈/em〉 L. and 〈em〉Agrostis pouretti〈/em〉 L. Leaf litter lignin, N and C concentrations, total phenolics, and fungal biomass were measured on both litter species for the assessment of litter quality. A higher preference for cork-oak litter from the conventional site was observed, both in isopods collected from the organic farm and from the conventional farm. This can be explained by the significant differences in litter quality that were found between 〈em〉Quercus〈/em〉 litter types collected in the two farms. The differences in the nutritional content (lower C:N ratio for 〈em〉Quercus〈/em〉 of the conventional farm) of litter from the same plant species support the assumption of a management effect on decomposition by changing plant litter quality. Yet, this pattern was not found for the other plant litter tested in this study – the grass species 〈em〉Agrostis pouretti〈/em〉. Also, despite the remarkable differences in litter traits between 〈em〉Quercus〈/em〉 and 〈em〉Agrostis〈/em〉, no significant differences were found between the ingestion rates of the litter from the two plant species. Although, depending on the plant species, litter quality resulting from different management influenced 〈em〉P. dilatatus〈/em〉 feeding preferences and ingestion rates.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Nizar Hmaeid, Mariem Wali, Ouissal Metoui-Ben Mahmoud, José J. Pueyo, Tahar Ghnaya, Chedly Abdelly〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work aims to characterize native bacteria from the saline rhizosphere of 〈em〉Sulla carnosa〈/em〉 and to identify promising rhizobacteria isolates able to ameliorate the salt tolerance of this species. Bacteria were screened 〈em〉in vitro〈/em〉 for salt tolerance capacity and plant growth promoting characteristics (PGP). Selected NaCl-tolerant bacteria showing a high PGP potential were further characterized for plant promotion effects on the growth of 〈em〉S. carnosa〈/em〉 under salt stress (200 mM NaCl). Three putative salt-tolerant strains that showed multiple PGP-traits identified as 〈em〉Acinetobacter〈/em〉 sp. (Br3), 〈em〉Pseudomonas putida〈/em〉 (Br18) and 〈em〉Curtobacterium〈/em〉 sp. (Br20) were selected for inoculation study. In a greenhouse experiment, NaCl significantly disturbed physiological parameters in non-inoculated 〈em〉S. carnosa〈/em〉. In these plants, NaCl reduced growth, increased foliar proline and malondialdehyde concomitant to Na〈sup〉±〈/sup〉 shoot concentrations. However, bacterial inoculation with selected PGP isolates ameliorated significantly plant growth and alleviated salt-induced physiological disturbances. Hence, as compared to non-inoculated plants, inoculation provided a significant increase in dry biomass and increased photosynthetic efficiency and chlorophyll leaf content under saline condition. Additional analysis showed that microbial inoculation also enhanced total soluble sugars content and antioxidant enzymes activities thereby preventing reactive oxygen species (ROS)-induced oxidative damage in plants. These results suggest that the inoculation of NaCl-stressed plants with selected salt-tolerant PGPR inocula exert beneficial effects on plant growth by alleviating salt-induced toxicity stress on plant growth and development.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): J. Karungi, S. Cherukut, A.R. Ijala, J.B. Tumuhairwe, J. Bonabana-Wabbi, E.A. Nuppenau, M. Hoeher, S. Domptail, A. Otte〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Unravelling how earthworms and ants are deterministically structured by abiotic and biotic factors is of utmost relevance in fostering favourable environments for their increased abundance and action, more so in the increasingly degraded agricultural ecosystems of mountainous regions in sub-Saharan Africa. The Mount Elgon region (MER) of Uganda is characterised by mosaics of farmlands dominated by Arabica coffee with variability in inclusion of companion crops and shade trees, and in use of organic and inorganic fertilizers; and elevation. In this paper we explored abundance of soil macrofauna and microclimate patterns in different cropping systems at varying mountain elevations. The study covered 72 coffee fields delineated by 3 elevation categories: low, mid and high; and 4 cropping systems: Coffee monocrop (C), Coffee + annual crop (C + A), coffee + banana (C + B), and coffee + banana + shade trees (C + B + T). Results indicated that ant abundance at high elevation was thrice that of low and was same order of magnitude in unshaded than in banana- and tree-shaded systems. Earthworm abundance followed a different trend, decreasing with altitude except in C + B and C + A systems. Some of these relationships could be explained by ambient temperature, light intensity and soil electrical conductivity in the systems. Earthworms preferred less-illuminated shaded coffee systems at warmer low-mid elevations and soils with relatively high electrical conductivity whereas ants’ counts were depressed by such systems, and mostly driven by cooler higher elevations. These results show that agricultural practices at the field scale have notable impact on abundance of macrofauna that provide ecosystem services and need consideration when working towards sustainability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Qichun Zhang, Hua Jin, Huifang Zhou, Mei Cai, Yong Li, Gengmiao Zhang, Hongjie Di〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An anaerobic incubation experiment was conducted to evaluate the impacts of different fertilizer treatments on the activity and diversity of anaerobic bacteria combined anammox process. The treatments included no fertilization (CK), inorganic fertilization (IF), pig manure combined with inorganic fertilization (PF), and straw combined inorganic fertilization (SF) during wheat and rice seasons. Various 〈sup〉13〈/sup〉C-PLFAs, especially 14:0, 16:1ω9c, 16:1ω5c, 16:0, 18:1ω9c, and 18:0, played significant roles in the anammox reaction and could be biomarkers of anammox. Additionally, fertilizer practices and seasonal changes could significantly affect soil properties, microbial biomass, and bacterial community structure. The abundance of total 〈sup〉13〈/sup〉C and anaerobic microbes was higher in the PF and SF treatments than in the IF and CK treatments in the same season, indicating anaerobic activity and abundance can be enhanced by applying organic–inorganic compound fertilizers. The anammox microbial abundance, marked by the 〈sup〉13〈/sup〉C-PLFAs 14:0, 16:1ω9c, 16:1ω5c, 16:0, 18:1ω9c, and 18:0, increased significantly during the crop rotation from the wheat season to the rice season. The proportions of bacteria were higher than those of fungi however the proportions of fungi were much higher than those of actinomycetes in all soils, suggest that fungi also play an important role in metabolizing the 〈sup〉13〈/sup〉C-matrix with strong anaerobic activity.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Anaerobic ammonia oxidation (anammox) is an important pathway in the microbial nitrogen cycle that allows ammonia to be oxidized by nitrite under anoxic conditions.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0929139318308606-ga1.jpg" width="363" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): M.E. Mitchell, T.L. Hamilton, C. Uebel-Niemeier, K.N. Hopfensperger, I. Buffam〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Green roofs typically consist of an engineered soil paired with drought-tolerant plants installed on a rooftop. These emerging ecosystems are installed for the services they provide, which in many cases depend on plant performance. In terrestrial ecosystems, nitrogen (N) is most often the limiting nutrient for plant productivity and its availability is heavily influenced by soil microorganisms. However, little is known about the green roof microbiome or their influence on N availability. We employed 16S rRNA and 〈em〉nifH〈/em〉 gene sequencing to assess the presence of nitrifying and nitrogen-fixing prokaryotes and their relationships to evidence of nitrification (runoff fluxes of nitrate and gaseous fluxes of nitrous oxide) and N fixation (presence of plants with symbiotic nitrogen-fixers) on 6 green roofs near Cincinnati, Ohio, USA. Our data indicate that green roofs in this region are a net source of reactive N: the majority of roofs released elevated nitrate levels in runoff relative to precipitation inputs, and also emitted N〈sub〉2〈/sub〉O, although at low rates comparable to those in natural ecosystems. We also recovered abundant 〈em〉nifH〈/em〉 genes affiliated with Rhizobiales and observed root nodules on leguminous plants on 5 of the 6 studied roofs, together indicating active N fixation. Our findings suggest N loss from green roofs could be alleviated by applying nitrification inhibitors, and that fostering plant-microbe N fixing communities could reduce the need for fertilizer amendments. Our data also highlight the role of microbial N cycling on green roofs and underscore the need for further work to quantify N-processing rates.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): María R. Landriscini, Juan A. Galantini, Matías E. Duval, Julia E. Capurro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cover crops (CC) provide many benefits for the soil and the following crop but their effects on nitrogen (N) release and balance in continuous no-tillage soybean (〈em〉Glycine〈/em〉 max L. Merr.) production are little known. Estimation of the biological nitrogen fixation (BNF) in intensive agricultural systems under soybean is essential to understanding the N dynamics and to determining the balances and crop demands. This study (2006–2011) was performed on a Typic Argiudoll under no-tillage in the province of Santa Fe, Argentina. The aims were to study the effect of fall winter CC, such as wheat (W), oats (O), oats + vetch (O + V) and vetch (V), on the yield and N-content of the following crop (soybean) and to quantify the contribution of the BNF and N-balance. Three methodologies were used for BNF estimation: 1) a linear regression model between BNF and N-uptake by soybean; 2) the natural 〈sup〉15〈/sup〉N abundance in soybean and 3) the average BNF in the Pampa region. Gramineous CC developed more dry matter than pure legume species, with intermediate values for the gramineous-legume mixture. Biological fixation provides 60–70% of absorbed N, according to the estimation method. Within the rainfall range of 500–1000 mm during the soybean cycle, CC did not affect the grain yield or soybean dry matter production. The partial N-balance was always positive, with differences between the techniques used for BNF estimation. Cover crops have contributed to the positive soil N-balance. Gramineous CC stored 22% more N-content in the soil surface layer than the others. Cover crops showed 15% higher index of N-stratification on the surface compared to the control soil. Using CC would be an efficient alternative to produce biomass and to supply N to the soil for the subsequent crop.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Guiping Ye, Yongxin Lin, Deyan Liu, Zengming Chen, Jiafa Luo, Nanthi Bolan, Jianbo Fan, Weixin Ding〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Addition of organic materials is believed to be a feasible practice for mitigating Ultisols acidification and loss of soil organic carbon (SOC). However, how organic materials mitigate acidification, affect SOC content and aggregation and shift microbial community structure requires further investigation. In this study, we used high-throughput sequencing of microbial DNA to evaluate the relationships between soil properties, aggregation and prokaryotic communities in soil subjected to 27 years of inorganic and organic fertilization. The field experiment included seven treatments: no fertilization (control), inorganic NPK fertilizer (I), inorganic NPK fertilizer plus liming (CaCO〈sub〉3〈/sub〉) (IL), and inorganic NPK fertilizer plus peanut straw (IPS), rice straw (IRS), radish (IR), or pig manure (IPM). Amendment with NPK fertilizer plus pig manure more effectively increased soil pH, SOC, total nitrogen (TN), available phosphorus (AP) and dissolved organic carbon (DOC) compared with NPK fertilizer plus crop residues. IPM also increased the mass proportion of large macroaggregates (〉2000 μm) from 7.8% in the control to 30.6% while it reduced effective diffusion coefficient of oxygen (DC〈sub〉o〈/sub〉) from 12.58 × 10〈sup〉−6〈/sup〉 m〈sup〉2〈/sup〉 s〈sup〉−1〈/sup〉 in the control to 2.81 × 10〈sup〉−6〈/sup〉 m〈sup〉2〈/sup〉 s〈sup〉−1〈/sup〉. Application of pig manure increased prokaryotic diversity and altered prokaryotic community structure, while crop residues did not. Soil pH was the predominant factor influencing prokaryotic community structure. 〈em〉Bacillales〈/em〉 and 〈em〉Clostridiales〈/em〉 accounted for 47.5% and 21.4%, respectively of the indicator species in the IPM and the relative abundances of them were increased, compared with the other treatments. Furthermore, the relative abundances of 〈em〉Bacillales〈/em〉 and 〈em〉Clostridiales〈/em〉 were correlated with SOC, TN, AP and DOC, and negatively with DC〈sub〉o〈/sub〉 in the soil. Overall, our results suggest that application of NPK fertilizer plus pig manure rather than crop residues enhanced soil pH, improved SOC content and aggregation, increased prokaryotic diversity and altered community structure of prokaryote after 27-year fertilization.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Gerhard C. du Preez, Mieke S. Daneel, Victor Wepener, Hendrika Fourie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Irrigated crop production, which accounts for 40% of global produce, is threatened by the deterioration of freshwater resources as a result of pollution originating from anthropogenic activities. While the effects of irrigating with low quality water on crop yield and quality is well appreciated, little remains known about the threat posed to soil ecosystems. The present study represents, with nematodes as bioindicators, the ecological line of evidence (of the TRIAD approach) and is aimed at evaluating the soil health status of farmlands associated with the Hartbeespoort, Crocodile (West), and Marico-Bosveld (reference system) irrigation schemes (South Africa). Irrigation water and soil samples were collected during the winter and summer growing seasons of 2016 and analysed for physico-chemical properties [pH, electrical conductivity, organic carbon content, particle size distribution, and metal, nutrient (inorganic nitrogen and phosphorus), and salt (chloride, fluoride, sulfate, calcium, magnesium, potassium, and sodium) concentrations]. Results indicated that the Hartbeespoort and Crocodile (West) irrigation schemes utilized water with an increased salinity (as indicated by the electrical conductivity) and inorganic nitrogen and phosphorus concentrations. The associated soil ecosystems were classified, using nematode-specific indices, as either degraded or disrupted. However, the reference system also presented degraded or disrupted soil ecosystems, which suggests that irrigation water quality was not the main factor influencing soil ecosystem health. Instead, it is likely that conventional farming practices (e.g. tillage) were the main drivers behind the observed disruptive effects. A redundancy analysis triplot evidenced a strong correlation between inorganic nitrogen, crop production, and nematode r-strategists, indicating that the nematode assemblages responded rapidly to agricultural activities such as the addition of fertilizers. No significant influence of irrigation water quality on soil ecosystem health was thus evidenced.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Benjamin Pey, Cécile Trân, Pablo Cruz, Mickaël Hedde, Claire Jouany, Christophe Laplanche, Johanne Nahmani, Eric Chauvet, Antoine Lecerf〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Millipedes (Diplopoda) and terrestrial isopods (Isopoda) may play a significant role in soil decomposition. The present study aimed to contribute to the general understanding of feeding performances of macrodetritivores consuming grass litter by answering two questions. Q1: Are grass litter traits indicating nutritive value (i.e. chemical) and traits indicating feeding deterrents (i.e. mainly physical but not necessarily) both necessary to explain individual feeding performances of soil invertebrates consuming grass litter? Q2: Do grass physical traits indicating physical deterrents (〈em〉e.g.〈/em〉 WHC for mechanical aspects) provide more than, less than or the same amount of information about invertebrate individual performances as grass chemical traits indicating mainly chemical but also physical deterrents (〈em〉e.g.〈/em〉 lignin content directly for digestibility and indirectly for mechanical aspects)? We thus designed a laboratory experiment to assess individual feeding performances of two common macrodetritivores (〈em〉Armadillidium vulgare〈/em〉 (Latreille, 1804) and 〈em〉Glomeris marginata〈/em〉 (Villiers, 1789)) in four monospecific treatments of litter from perennial forage grasses (〈em〉Brachypodium pinnatum〈/em〉 P. Beauv., 〈em〉Bromus erectus〈/em〉 Huds., 〈em〉Festuca rubra〈/em〉 L. and 〈em〉Holcus lanatus〈/em〉 L.). 〈em〉A. vulgare〈/em〉 feeding performances were correlated with nutritive values (litter N and P contents) and plant mechanical aspects (LDMC: leaf dry matter content). 〈em〉G. marginata〈/em〉 performances were correlated with chemical deterrents (cellulose and lignin contents). Thus, (Q1) for grass litters, both traits indicating nutritive value (〈em〉e.g.〈/em〉 N, P) and feeding deterrents (〈em〉e.g.〈/em〉 LDMC, lignin content) are necessary to explain macroinvertebrates feeding performances. We also demonstrated the results depend on the invertebrate species considered. Also, (Q2) chemical deterrents may influence feeding performances of 〈em〉G. marginata〈/em〉 the most, while physical deterrents related to mechanical aspects may influence those of 〈em〉A. vulgare〈/em〉 the most. Our study shows that using grass chemical and physical traits that indicate both nutritive value and feeding deterrents can help explain feeding performances of macrodetritivores.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Rafaella Santana Santos, Hosana Haum Barros Mecenas, Leandro Sousa-Souto〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The time interval in which a community plant recovers after a disturbance is strongly associated with the availability of nutrients and soil organic matter, factors that are widely known as limiting for the establishment of pioneer species. The nest refuse (NR) produced by leaf cutting ants may act to favour herbaceous regeneration in newly disturbed areas, but little is known about its effects in this process. In the present study, we experimentally verified the effect of NR on plant regeneration in a newly deforested area, testing the hypothesis that plots with NR act as hot spots for plant establishment, promoting greater aboveground biomass and altering the vegetation structure in comparison to control sites. Thirty plots of 30 × 30 cm were installed, where half of the plots received a layer of 3 cm of soil from the same site (control) while the other plots received a layer of 3 cm of a mixture of control soil + NR, in a 3:1 ratio (25% organic refuse). After 150 days of natural regeneration, we evaluated the diversity of herbaceous species that colonised each plot and the aboveground dry biomass. The species composition differed between treatments and the aboveground biomass was 45% higher in the plots with NR than control soil. In this way, refuse dumps can act as regeneration sites, favouring pioneer species in newly deforested areas.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Jinyu Hou, Wuxing Liu, Longhua Wu, Yanyan Ge, Pengjie Hu, Zhu Li, Peter Christie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hyperaccumulator plants combined with beneficial bacteria is a promising strategy for extracting trace metals from contaminated soils. We explored how the rhizosphere microbiome reshaped by exogenous functional bacteria and whether there is a relationship between the reshaped rhizosphere microbiome and Cadmium (Cd) accumulation in the hyperaccumulator plant during this process. A pot experiment was set up and the Cd hyperaccumulator 〈em〉Sedum plumbizincicola〈/em〉 was planted with and without a plant beneficial bacterial strain 〈em〉Rhodococcus〈/em〉 sp. NSX2. High-throughput sequencing and random matrix theory (RMT)-based network analysis were used to track the bacterial community in both the rhizosphere and the bulk soil. We found that NSX2 survived in the rhizosphere with a high relative abundance of 1.46% and reshaped the whole bacterial community structure in the rhizosphere. NSX2 inoculation significantly increased Cd accumulation in 〈em〉S. plumbizincicola〈/em〉 and the phytoremediation efficiency strongly correlated with the reshaped bacterial network topology. Moreover, NSX2 made the bacterial network in the rhizosphere more complex through cooperating positively with the indigenous bacteria while the network in the bulk soil remained unchanged. We conclude that bacterial inoculation-enhanced phytoremediation did correlate with the beneficial bacterium inoculated itself and also with the subsequently changed indigenous rhizosphere bacterial community and their interactions at the whole community level.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Jinliang Liu, Vu Ngoc Ha, Zhen Shen, Hailan Zhu, Fei Zhao, Zhong Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil microbial community composition and diversity were significantly affected by tree species, growth stage and soil nutrients in the forest ecosystem. We analyzed the bulk and rhizosphere soil microbial communities associated with young (20 year) and old (1000 year) trees of 〈em〉Platycladus orientalis〈/em〉 using 16S and ITS rRNA high-throughput gene sequencing techniques. 〈em〉Platycladus orientalis〈/em〉 growth altered the nutrient and microbial community compositions in the bulk and rhizosphere soils. In a typing analysis, the bacterial and fungal communities clustered into two and three groups, respectively, and only the fungal diversity exhibited significant differences between the bulk and rhizosphere soils. Soil microbial community compositions in bulk and rhizosphere soils were dominated by 〈em〉Acidobacteria〈/em〉, 〈em〉Proteobacteria〈/em〉, 〈em〉Actinobacteria〈/em〉 and 〈em〉Ascomycota〈/em〉 phyla, and their changes were driven by the 〈em〉Gemmatimonadetes〈/em〉, 〈em〉Nitrospirae〈/em〉, 〈em〉Planctomycetes〈/em〉, 〈em〉Zygomycota〈/em〉 and 〈em〉Basidiomycota〈/em〉 phyla. Compared with soils under young trees, 24.63% and 72.80% of the bacterial and fungal genera in bulk soil and 24.78% and 59.92% of the bacterial and fungal genera in rhizosphere soil shifted in the old trees samples. Soil microbial community compositions were sensitive to changes of soil nutrients, which explained 82.10% and 86.79% of the total variation in the major bacterial and fungal genera community compositions, respectively. Our results suggest that long-term growth of 〈em〉Platycladus orientalis〈/em〉 trees significantly altered bulk and rhizosphere microbial community compositions, and its influence was greater on the fungal community than on the bacterial community.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Daniela Carnovale, Andrew Bissett, Peter H. Thrall, Geoff Baker〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The composition of native woody vegetation communities in restored agricultural landscapes can alter plant-soil interactions and thus ecological function. This study investigated the effects of primary species groups (〈em〉Acacia〈/em〉, 〈em〉Eucalyptus〈/em〉) used in shelterbelts in south-eastern Australia on soil microbial community structure, compared with those under adjacent pastures. The quantity and structure of bacterial and fungal communities was analysed using quantitative PCR (qPCR) and terminal restriction fragment length polymorphism (TRFLP). The fungal:bacterial ratio was highest under 〈em〉Eucalyptus〈/em〉 trees but did not differ between 〈em〉Acacia〈/em〉 and pasture. Both fungal and bacterial communities varied at different depths in the soil profile and across sampling periods. The dominant tree genus was a significant factor in observed differences in bulk soil bacterial and fungal communities compared to the surrounding pasture. The effect of tree type on fungal communities was more pronounced than on bacterial communities. Fungal communities not only differed between shelterbelts and pastures, but also between 〈em〉Acacia〈/em〉 and 〈em〉Eucalyptus〈/em〉 dominated shelterbelts; these patterns were consistently observed at different soil depths. Shelterbelt systems which contain a mixture of different plant genera have the potential to exhibit greater microbial community heterogeneity than single species plantations. Maintaining a variety of tree species during afforestation may therefore contribute to conserving important bacterial and fungal diversity in agricultural landscapes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Krishna B. Bhandari, Charles P. West, Veronica Acosta-Martinez, Jon Cotton, Amanda Cano〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉‘WW-B.Dahl’ Old World bluestem [OWB, 〈em〉Bothriochloa bladhii〈/em〉 (Retz) S.T. Blake] is a persistent pasture grass in the semi-arid Texas High Plains. Some growers are transitioning their irrigated continuous cotton (〈em〉Gossypium hirsutum〈/em〉 L.) land to dryland or low-irrigation production of WW-B.Dahl owing to diminished water supply. This grass strongly deters soil-dwelling ants (Hymenoptera: Formicidae), presumably via release of unidentified phytochemical repellants in the soil. Our aim was to determine whether the inhibitory effects of OWB extend to soil microbial community structure and function in relation to other adapted forages. We compared soil chemical and microbial properties in a Pullman clay-loam soil for OWB relative to OWB-alfalfa (〈em〉Medicago sativa〈/em〉 L.), alfalfa, and native mixed-grass pastures at 0–5 cm and 10–15 cm depth in June and December of 2016. The pastures ranged in age from 7 to 17 yr. Most measurements of organic forms of C and N showed greatest amounts in OWB-alfalfa; however, not always significantly. Enzyme activities linked to C, N, and S transformations were greatest (〈em〉P〈/em〉 ≤ 0.03) with OWB-alfalfa. This trend was similar for alkaline phosphatase activity, involved in P cycling, but not always significantly. Soil organic C in OWB was 1.2–1.4 fold greater than in the native mix depending on soil depth and sampling date, whereas SOC in OWB-alfalfa was 1.4–1.6 fold greater than in the native mix. Enzyme activities and microbial biomass N (MBN) were likewise greater in OWB and OWB-alfalfa than in the native mix, likely because the latter received no irrigation or N inputs. The microbial community structure demonstrated greater total FAMEs, bacterial markers for Gram+, Gram−, and actinomycetes in OWB-alfalfa compared to OWB, alfalfa, and native mix. Similar results were found in fungal markers for arbuscular mycorrhizal fungi (AMF) and saprophytic fungi. Protozoan indicators were found only in December, of which the native mix had the highest levels in the 0–5 cm depth. In general, selected soil properties, soil microbial biomass, community and enzyme activities were greater in December than in June except AMF, which was greater in June. The stimulating effect of OWB growing with alfalfa on the soil microbial community suggested this forage combination as favorable for soil health in relation to OWB, alfalfa alone, and native mixed-grass pastures. The previously reported inhibitory effect of OWB on soil-dwelling ants did not carry over to a depressing effect on the soil microbial component.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Nadia Vignozzi, Alessandro Elio Agnelli, Giorgio Brandi, Elena Gagnarli, Donatella Goggioli, Alessandra Lagomarsino, Sergio Pellegrini, Stefania Simoncini, Sauro Simoni, Giuseppe Valboa, Giovanni Caruso, Riccardo Gucci〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The long-term effects of two different soil management practices, natural grass cover (NC) and conservation tillage (CT), on soil functions (carbon sequestration, habitat for organisms, and water movement and retention) were determined in a high-density, mature olive orchard (〈em〉Olea europaea〈/em〉 L. cv. Frantoio) growing in a sandy loam soil (Typic Haploxeralf) in a Mediterranean environment. Ten years after the beginning of the different soil management, soil samples were collected at 0–10 and 10–20 cm depth and at two distances from the trunk, underneath the olive canopy (UC) and in the inter-row (IR). There were no differences in fruit yield, oil yield, and yield efficiency between the two soil management systems during the 2011–2013 period. CT negatively affected soil organic carbon pools (total and humified), but only at the IR position. The distance from the plant did not significantly influence soil structure and hydrological properties, while NC treatment increased water movement and retention. Tillage reduced the microarthropod abundance, in particular Collembola and eu-edaphic forms, which were the most sensitive groups to soil perturbation. We conclude that natural grass cover was more effective than conservation tillage in maintaining or improving elements of soil functionality.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Taru Sandén, Laura Zavattaro, Heide Spiegel, Carlo Grignani, Hans Sandén, Andreas Baumgarten, Marja Tiirola, Anu Mikkonen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Common soil characteristics, nutrients and microbial activity at deeper soil depths are topics seldom covered in agricultural studies. Biogeochemical cycles in deep soils are not yet fully understood. This study investigates the effect of different mineral and organic fertilisation on soil organic matter dynamics, nutrients and bacterial community composition in the first meter of the soil profiles in the long-term maize cropping system experiment Tetto Frati, near the Po River in northern Italy. The following treatments have been applied since 1992: 1) crop residue removal (CRR), 2) crop residue incorporation (CRI), 3) crop residue removal with bovine slurry fertilisation (SLU), 4) crop residue removal with farmyard manure fertilisation (FYM). A total of 250 kg N ha〈sup〉−1〈/sup〉 were applied annually as mineral fertiliser in the first two and as organic fertilizer in the latter two treatments. Soil organic carbon (SOC) was significantly higher in the treatments with organic amendments (CRI, SLU and FYM) compared to CRR in 0–25 cm (11.1, 11.6, 14.7 vs. 9.8 g kg〈sup〉−1〈/sup〉, respectively), but not in the deeper soil. At 75–100 cm soil depth, SLU and FYM had the highest potential N mineralisation. Bacterial diversity decreased down the soil profile much less than microbial biomass. Incorporation of crop residues alone showed no positive effects on either biomass or diversity, whereas fertilisation by FYM instead of mineral fertilizer did. Bacterial community composition showed depth-related shifts: Proteobacteria and Actinobacteria dominated the topsoil, whereas Chloroflexi, Nitrospira and Thermotogae were relatively more abundant deeper in the soil profile. Although the main factor determining soil bacterial community composition in the entire dataset was soil depth, both the size and diversity of bacterial community, as well as several discriminating taxa, were affected by organic N fertilisation down to 1 m depth. This calls for continued efforts to study the deeper soil depths in the numerous long-term field experiments, where mostly topsoils are currently studied in detail.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Jackie Dabrowski, Gustav Venter, Wayne F. Truter, Clarke H. Scholtz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dung beetles provide a multitude of ecosystem services that could be used to improve post-mining land use options. Highly compacted soils are a feature of reclaimed mine sites and may pose a significant challenge to tunnelling dung beetles. This study aimed to determine if dung beetles can tunnel into compacted soils, and how a range of soil penetration resistance may influence their tunnelling depth. Three beetle species were used: 〈em〉Onitis alexis〈/em〉 (Klug, 1835), 〈em〉Digitonthophagus gazella〈/em〉 (Fabricius, 1787) and 〈em〉Euoniticellus intermedius〈/em〉 (Reiche, 1849). Five individuals of each species (at an approximately even sex ratio) were placed on 30 separate 1 Kg cattle dung pats where they were left to tunnel for 14 days. Dung pats were placed on the soil surface covering a range of penetration resistance levels between 100 kPa and 5000 kPa. 〈em〉D. gazella〈/em〉 tunnels showed a negative correlation with increasing penetration resistance (p 〈 0.05; R〈sup〉2〈/sup〉 = 0.65). While 〈em〉O. alexis〈/em〉 tunnel depth showed no correlation with penetration resistance, 〈em〉E. intermedius〈/em〉 increased tunnel depth with increasing penetration resistance (p 〈 0.05; R〈sup〉2〈/sup〉 = 0.35). Although tunnelling depth was notably shallower than previously observed for 〈em〉E. intermedius〈/em〉, all three species could tunnel into the soil at the average penetration resistance of 3 193 kPa, and even beyond the maximum measurement limit of the penetrometer at 5 000 kPa.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Sandipan Samaddar, Poulami Chatterjee, Jaak Truu, Rangasamy Anandham, Sukjin Kim, Tongmin Sa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effects of phosphorus (P) availability on soil microbial community and its functional responses have not been widely explored till date. The present study involved high throughput sequencing of 16S rRNA to investigate the bacterial community structure, size and function in long-term fertilized paddy soils that received P fertilizers (+ P) and compared with soils without P fertilizer (− P) application. Data analysis revealed that changes in P availability in the soil significantly influenced the phylogenetic composition of bacterial communities and their functional profiles. The populations of bacterial phyla Verrucomicrobia, Bacteroidetes, Acidobacteria, Chloroflexi, and Cyanobacteria were significantly induced in (− P) treatment when compared with (+ P). The bacterial genus 〈em〉Geobacter〈/em〉 reported to use high-affinity P transporter during P limitation and 〈em〉Massilia〈/em〉 known as a prominent P solubilizer were significantly more abundant in (− P) soils. The functional profile analysis demonstrated (− P) soils were characterized by more abundant enzymes related to P cycling. The present study enabled us to characterize the dominant indigenous microbiome of (− P) soils and also provided a better insight into the ecological and evolutionary responses of microbes in P limited soils.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Joachim G.C. Deru, Jaap Bloem, Ron de Goede, Nyncke Hoekstra, Harm Keidel, Henk Kloen, Andreas Nierop, Michiel Rutgers, Ton Schouten, Jan van den Akker, Lijbert Brussaard, Nick van Eekeren〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Considerable nitrogen (N) mineralization occurs in drained peat soils in use for dairy grassland, due to aerobic decomposition of soil organic matter (SOM). N losses may be limited by matching grass N uptake with N mineralization and by adapting on-farm fertilization schemes to soil N supply (SNS) and apparent N recovery (ANR). Previous attempts to predict SNS of peat grasslands from soil parameters have been unsuccessful, partly due to high variation in SNS between sites and years. In this paper, we present field data from twenty dairy grasslands on drained peat (29–65% SOM; Terric Histosols). Grass yield parameters (e.g. SNS and ANR) were compared with a comprehensive data set of soil biotic and abiotic properties measured at the start of the growing season, and with N mineralization calculated from this data. SNS ranged between 171 and 377 kg N ha〈sup〉−1〈/sup〉 (mean: 264 kg N ha〈sup〉−1〈/sup〉) during the growing season. Soil N mineralization estimated by laboratory incubation and by foodweb-based production ecological calculations gave similar mean values with slightly higher coefficients of variation, but correlations with SNS were not significant. Regression analysis with soil properties showed a positive correlation between SNS and soil Ca:Mg ratio and a negative correlation between fertilized grass yield and soil C:SOM ratio. No significant models were found for ANR. Based on our data and on literature, we conclude that these parameters indicate linkages between grass yield and soil physical-hydrological properties such as soil structure and water availability. In particular, the C:SOM ratio in these soils with high organic matter content may be an indicator of water repellency, and our results suggest that grass growth was limited by drought more than by nutrient availability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Juliet Wanjiku Kamau, Lisa Biber-Freudenberger, John P.A. Lamers, Till Stellmacher, Christian Borgemeister〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The growth of organic agriculture (OA) in sub-Saharan Africa (SSA) raises the question of how far OA can improve the livelihoods of the many smallholder farmers that have to cope with numerous complex biophysical and socioeconomic challenges. Evidence on the impacts of OA in SSA, particularly on soil fertility and biodiversity, still is scarce and inconclusive. The aim of this study was therefore to evaluate and compare soil fertility, decomposition and biodiversity between 20 organic and conventional farms in two counties (Kajiado and Murang’a) in Kenya. Soil sampled at 0–20 cm depth was analysed for physical and chemical properties. The decomposition of crop residues over 3 months was studied using litterbags while pitfall trapping and the derived diversity indices provided insights into arthropod abundance and diversity. Differences in soil properties, mass loss through decomposition, and arthropod abundance were analysed with linear mixed models. Findings show no statistically significant differences in soil fertility, decomposition and abundance of arthropods between organic and non-organic farms. However, species richness and diversity of arthropods on organic farms was significantly higher than on non-organic farms. Overall, farms in Kajiado had higher soil fertility and arthropod diversity than those in Murang’a, while farms in Murang’a had a higher arthropod abundance. It is argued that similar agricultural practices used in organic and non-organic farming systems, irrespective of county and biophysical conditions, strongly influenced soil fertility and biodiversity. Our results demonstrate that OA has the potential to increase arthropod biodiversity, but its ability to sustain the health of soils depends on numerous factors that are likely to undermine OA efforts in this region.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Anissa Nurdiawati, Bakhtiyor Nakhshiniev, Hazel Bantolino Gonzales, Kunio Yoshikawa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Utilization and management of biomass residues are important global issues to ensure sustainability in agricultural production. Among biomass residues, a feather is one of the excellent raw materials for fertilizer because it has high nitrogen (N) content. Through hydrolysis, liquid feather hydrolysates could be obtained that are potentially desirable for use in agriculture practices. However, knowledge about the nutrient-release characteristics of liquid hydrolysates from organic materials in relation to production process parameters is lacking. In this study, four liquid feather hydrolysates produced by hydrothermal treatment (HTT) under various temperatures and one commercial liquid fertilizer were added to two adjacent soils and evaluated for N mineralization behavior in a 30-day incubation study. At the end of the incubation, the net N mineralization for hydrolysate-amended kuroboku soil was in the range of 34%–43% and for hydrolysate-amended paddy soil was in the range of 38%–51%. Soil type strongly influenced the net N mineralization more than the fertilizer treatments. For all treatments and soils, NH〈sub〉4〈/sub〉-N content increased while NO〈sub〉3〈/sub〉-N content remained constant, indicating delayed nitrification. The first-order exponential model expressed the rate of N mineralization, in which the parameters indicated that HTT products obtained at a higher temperature mineralize faster than ones obtained by a lower-temperature treatment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Dorra Ben Abdallah, Slim Tounsi, Olfa Frikha-Gargouri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Several factors may affect the success of biocontrol agents in the field, some of which are sparsely studied. This work aimed to evaluate the influence of the inoculum type of 〈em〉Bacillus amyloliquefaciens〈/em〉 subsp. 〈em〉plantarum〈/em〉 32a on the production of antibacterial metabolites, the colonization level of tomato and the control efficacy of crown gall disease. When 32a cells were grown in the optimized medium, spore inoculum yielded approximately 10 fold more anti-〈em〉Agrobacterium〈/em〉 activity than vegetative inoculum. LC-MS analysis showed that spore inoculated culture produced a pronounced shift toward shorter alkyl chains for surfactins (C13 and C14). When applied to the soil, 32a successfully colonized roots, stem and leaves of tomato. Higher population density was obtained during the treatment of soil with spores, compared to that with vegetative cells. The crown gall disease symptoms, caused by 〈em〉A. tumefaciens〈/em〉, were reduced by strain 32a at different extent depending on the inoculum type treatment. A more pronounced protection was obtained when 32a spores were used for soil inoculation.〈/p〉 〈p〉In this study, we showed for the first time that the inoculum type is one of the important factors affecting the success of a biocontrol agent. This information has significant implications in improving the efficacy of biopesticides.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): B. Guimarães, V.L. Maria, J. Römbke, M.J.B. Amorim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The potential implications of long-term exposure to contaminants are not covered by current standard toxicity guidelines, usually referring to one generation and a fraction of the life cycle of the test species. Hence, in the present study, we aimed to assess the effects of the multigenerational exposure (generation 1–3: F1-F3) of 〈em〉Folsomia candida〈/em〉 to an insect growth regulator (IGR) compound: teflubenzuron (TFB). The selected endpoints included both the standard ones as in the OECD and ISO guidelines (survival, reproduction, and avoidance) as well as additional ones (organisms size and cellular oxidative stress markers: acetylcholinesterase, glutathione S-transferase, catalase, glutathione peroxidase, lipid peroxidation). Although no avoidance behaviour was recorded at field-relevant concentrations (PEC (Predicted Environmental Concentration) = 0.06 mg/kg soil dry weigh (dwt)), survival and reproduction were impacted (LC50 = 0.1 mg/kg soil dwt; EC50 = 0.05 mg/kg soil dwt). Multigenerational exposure to TFB caused increased toxicity in 〈em〉F. candida〈/em〉 in F3 in terms of survival and reproduction. This could be related to the mode of action of TFB which does not seem to activate some of the general stress mechanisms of response like oxidative stress. In addition, TFB causes a reduction of the organisms’ size, with a reduction of the number of large-sized juveniles, which has potential adverse consequences in terms of organisms’ performance, e.g. change in age structure and hence population dynamics. Hence, both observations may increase the environmental concern and associated risk of this insecticide.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Yousry Bayoumi, Naglaa Taha, Tarek Shalaby, Tarek Alshaal, Hassan El-Ramady〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Onion is one of the most important export crops in Egypt; its productivity and exportation is restricted mainly by purple blotch disease. 〈em〉In vitro〈/em〉 and field experiments during two growing seasons were conducted aiming to improve control of 〈em〉Alternaria porri〈/em〉 (the pathogen causing purple blotch disease) by the application of combinations of elemental sulfur (S〈sup〉0〈/sup〉) and 〈em〉Trichoderma〈/em〉 spp. (〈em〉T. harzianum〈/em〉 and 〈em〉T. viride〈/em〉). Fungicide (Ridomil Gold M Z-68% WG) was applied as pesticide treatment control. 〈em〉In vitro〈/em〉 experiments revealed that supplementation of S〈sup〉0〈/sup〉 at 2 g L〈sup〉−1〈/sup〉 to the growth medium that was utilized to culture 〈em〉Trichoderma〈/em〉 spp. inhibited (100%) the growth of 〈em〉Alternaria porri〈/em〉. 〈em〉Trichoderma viride〈/em〉 showed higher efficiency in controlling purple blotch than 〈em〉T. harzianum〈/em〉, and resulted in disease controlling rates that were similar to those by fungicide (Ridomil Gold). Disease incidences decreased by 63.9% in onion plants that were inoculated with 〈em〉T. viride,〈/em〉 compared to 66.3% when fungicide was applied. Also, antioxidant activity of catalase and peroxidase was the highest when S〈sup〉0〈/sup〉 was applied at 240 kg ha〈sup〉−1〈/sup〉 and the onion plants were treated with 〈em〉T. harzianum〈/em〉 and/or 〈em〉T. viride〈/em〉. Application of S〈sup〉0〈/sup〉 at 240 kg ha〈sup〉−1〈/sup〉, in combination with inoculating onion seedlings with 〈em〉T. harzianum,〈/em〉 led to enhanced onion growth and yield over fungicide application (traditional practice of farmers) in both seasons. As a result, green bulb yield (t ha〈sup〉−1〈/sup〉) and total soluble solids (TSS, %) were 41.9 and 21.7% higher, respectively; harvested dry bulb (t ha〈sup〉−1〈/sup〉), marketable bulb yield and TSS were 33, 35 and 13% higher, respectively; while nonmarketable bulb yield was 21.5% lower than those under fungicide application.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Changliang Jing, Zongchang Xu, Ping Zou, Qi Tang, Yiqiang Li, Xiangwei You, Chengsheng Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil microbial community and extracellular enzymes play an important role in soil biochemical reactions and biogeochemical cycles. In this study, we evaluated the influence of cultivated halophytes on soil enzyme activity and soil microbial composition in the Yellow River area. We selected two local halophytes—〈em〉Atriplex triangularis〈/em〉 and 〈em〉Suaeda glauca〈/em〉—as models. We initially investigated the effects of cultivation of the two halophytes on soil properties and enzyme activities. Subsequently, we evaluated the effects on the bacterial community structure using 16S rRNA gene sequencing studies. Soil salinity, organic matter, and Na〈sup〉+〈/sup〉 concentration were significantly higher in the rhizosphere than in the bulk soil for both halophytes studied. Significantly higher urease and dehydrogenase activities were observed in the rhizosphere of 〈em〉A. triangularis〈/em〉 than in that of 〈em〉S. glauca〈/em〉. Significant differences in bacterial community structure between the rhizosphere of 〈em〉S. glauca〈/em〉 and the associated bulk soil mainly involved the phyla 〈em〉Acidobacteria〈/em〉, 〈em〉Proteobacteria〈/em〉, 〈em〉Bacteroidetes〈/em〉, and 〈em〉Chloroflexi〈/em〉. In the case of 〈em〉A. triangularis〈/em〉, these differences involved 〈em〉Proteobacteria〈/em〉, 〈em〉Bacteroidetes〈/em〉, 〈em〉Chloroflexi〈/em〉, 〈em〉Actinobacteria〈/em〉, and 〈em〉Acidobacteria〈/em〉. In conclusion, cultivation of these two halophytes could assist in desalinization, altered rhizosphere and bulk soil properties, altered enzyme activities, and shifts in bacterial populations. The results contributed to our understanding of the effects of halophyte cultivation on coastal ecosystem phytoremediation, specifically in the context of the Yellow River Delta.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Ricardo A.C. Oliveira, Renato Marques, Márcia C.M. Marques〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One of the challenges in predicting the effects of biodiversity on ecosystem functioning is understanding the balance between the importance of various diversity components and variations in the environment. In mega-diverse tropical forests, these relationships between plant diversity and ecosystem processes, such as litter decomposition, are poorly explored. While the direct effects of plant diversity on litter decomposition are relatively well known, the indirect effects of diversity, and the local community and microenvironment have rarely been investigated. We evaluated the indirect effects of plant diversity on litter decomposition in a tropical forest. We assessed diversity using different components (plant species richness, functional composition, and functional diversity), evaluated the environmental gradient (soil attributes, topography and canopy cover) and related it to the dynamics of litter decomposition. A 230-day 〈em〉in situ〈/em〉 experiment was performed in the southern areas of the Brazilian Atlantic forest using litterbags filled with standard substrate (to test the indirect effects) to evaluate the decomposition rates. In parallel, we also conducted a taxonomic and functional survey of the vegetation in the area of influence of the decomposition experiment. We demonstrated that there is an indirect effect of plant diversity, via taxonomic and functional diversities, on litter decomposition. The indirect effect is more pronounced at the beginning of the decomposition process, and the influences of different components of diversity and ecological mechanisms (niche complementarity, mass effect and selection effect) vary over time. Our study revealed the importance of not only small-scale variations in the biotic component but also those of soil in ecosystem functioning in a megadiverse forest. In this way, we have contributed to a better understanding of the determinants of the decomposition process, in addition to those suggested by classical theoretical models (i.e., climate, litter composition and decomposers).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Mette Vestergård〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The northern root-knot nematode, 〈em〉Meloidogyne hapla〈/em〉, is an increasing problem in organic vegetable production in Northern Europe. Lack of resistant cultivars, 〈em〉M. hapla〈/em〉’s ability to use a wide spectrum of hosts, including many common weed species, as refuge and lack of consistently efficient mitigation measures call for clever integration of several control strategies. Here trap crop strategies are reviewed. Dead-end trap crops are poor hosts that are infected by 〈em〉M. hapla〈/em〉, but restrict the development and reproduction of the nematodes inside the roots. The susceptible trap crop strategy employs good host plants that are mulched before the nematodes inside the root tissues reach maturity and start reproduction. This review presents plant species that have been employed as trap crops for 〈em〉M. hapla〈/em〉 and evaluate their applicability and pinpoint pitfalls of the strategy. Further, the review outlines supplementary management measures (trap crop uprooting, black fallow, cover crops and biofumigation) that can be integrated with trap crops to ensure efficient reduction of 〈em〉M. hapla〈/em〉 infection risk for subsequent susceptible vegetable crops.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Lea Carlesso, Andrew Beadle, Samantha M. Cook, Jess Evans, Graham Hartwell, Karl Ritz, Debbie Sparkes, Lianhai Wu, Phil J. Murray〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil compaction is a major threat to agricultural soils. Heavy machinery is responsible for damaging soil chemical, physical and biological properties. Among these, organic matter decomposition, which is predominantly mediated by the soil biota, is a necessary process since it underpins nutrient cycling and the provision of plant nutrients. Understanding factors which impact the functionality of the biota is therefore necessary to improve agricultural practices. To better understand the effects of compaction on the soil system, we determined the effects of soil bulk density and soil penetration resistance on the decomposition rates of litter in three distinct field zones: a grass margin, sown at the edge of the field adjacent to the crop, tramlines in the crop:margin interface, and crop. Three litters of different quality (ryegrass, straw residues and mixed litter) were buried for 1, 2, 4 and 6 months in litter bags comprising two different mesh sizes (0.02 and 2 mm). Bulk density and soil penetration resistance were greater in the compacted tramline than in the margin or the crop. The greatest amount of litter remaining in the bags after 6 months was found in the tramline, and the least in the grass margin. Differences between treatments increased with burial time. No significant differences in mass loss between the two mesh sizes was detected before the fourth month, implying that microbial activities were the main processes involved in the early stages of decomposition. Decomposition in the tramline was clearly affected by the degradation of soil structure due to heavy compaction. This study shows that soil conditions at the edges of arable fields affect major soil processes such as decomposition. It also reveals the potential to mitigate soil degradation by managing the headland, the crop residues and the machinery traffic in the field.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 134〈/p〉 〈p〉Author(s): Claudina M. Hack, Miriam Porta, Rudi Schäufele, Agustín A. Grimoldi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil symbiotic microorganisms promote recruitment of legume forage species in grassland ecosystems by enhancing provision for nutrients. We studied the effects of arbuscular mycorrhizal fungi (AMF) on plant growth, mineral nutrition and biological nitrogen fixation of 〈em〉Melilotus alba〈/em〉 Med., a forage legume with potential use in subtropical grasslands. Responses to AMF inoculation (a mix of 〈em〉Funneliformis mosseae, Rhizophagus irregularis〈/em〉 and 〈em〉Simiglomus hoi〈/em〉) and phosphate fertilization were evaluated in plants growing for 12 weeks in a subtropical soil. All plants were previously inoculated with a suspension of 〈em〉Rhizobium meliloti〈/em〉. Plant responses were assessed in terms of mycorrhizal colonization, biomass production, mineral nutrition (P and N) and proportion of biological nitrogen fixation by 〈sup〉15〈/sup〉N natural abundance method. The results showed that when soil phosphorus availability was very low, regardless of the degree of AMF colonization, the generation of mycorrhizae did not reach a significant impact on plant nutrition and biomass production. But under a relatively higher phosphorus provision, AMF symbiosis showed positive effects on phosphorus accumulation, nitrogen nutrition and biomass production, linked to an enhancement of biological nitrogen fixation. The results strengthen our understanding of how synergistic effects between belowground symbionts (in this case AMF + 〈em〉Rhizobium〈/em〉) could promote the recruitment of forage legumes in subtropical grassland soils.〈/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-S0929139318306760-ga1.jpg" width="288" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Wayne L. Silver, Albert H. Kim, Eui Y. Kim, Cecil J. Saunders〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Earthworms have a profound effect on the soil they inhabit, but our current understanding of the chemical factors and molecular mechanisms that attract or repel earthworms from a specific area of soil is limited. In this study, we developed a soil T-maze assay allowing for the examination of earthworm behavioral responses to repellent chemicals. This tests earthworms individually, and thus the potential confounds of worms being influenced by conspecifics signals are avoided. Canadian nightcrawlers (〈em〉Lumbricus terrestris〈/em〉) can detect the canonical Transient Receptor Potential Ankyrin 1 (TRPA1) agonist, allyl isothiocyanate (AITC), but not the canonical Transient Receptor Potential Vanilloid 1 (TRPV1) agonist capsaicin. In the T-maze assay 〈em〉L. terrestris〈/em〉 avoided TRPA1 activators AITC, cinnamaldehyde and menthol in a dosage dependent manner. The single subject T-maze assay is a useful tool to study the avoidance of earthworms to chemical compounds and provides behavioral evidence for a TRPA1 ortholog in 〈em〉L. terrestris.〈/em〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Daihua Ye, Dan Liu, Tingxuan Li, Xizhou Zhang, Zicheng Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Land-applied poultry manure threatens to water environments, particularly because of its high concentration of phosphorus (P). 〈em〉Polygonum hydropiper〈/em〉 is efficient in extracting soil excess P, thereby reducing the risk of P runoff and leaching. Rather, little is understood about the effects of poultry manure on soil properties and the P-accumulating characteristics of this plant species. Two pot experiments were conducted to investigate P accumulation and rhizosphere properties in a mining ecotype (ME) of 〈em〉P. hydropiper〈/em〉 from Shifang phosphate-mining area and the contrasting non-mining ecotype (NME), with the first experiment at different poultry manure application rates (0, 25, 50, 75, 100 g kg〈sup〉−1〈/sup〉 dry soil) and the second experiment under the optimum poultry manure concentration (75 g kg〈sup〉−1〈/sup〉) over three growth periods. The ME’s shoot biomass and P accumulation increased with poultry manure application rates up to 75 g kg〈sup〉−1〈/sup〉 and increased with increasing growth periods. Shoot biomass and P accumulation of the ME were significantly greater than those of the NME at 75 g kg〈sup〉−1〈/sup〉 in both experiments. At the optimum poultry manure rate (75 g kg〈sup〉−1〈/sup〉), H〈sub〉2〈/sub〉O-Pi (Pi, inorganic P), H〈sub〉2〈/sub〉O–, NaHCO〈sub〉3〈/sub〉− and NaOH-Po (Po, organic P) were more depleted in ME rhizosphere than NME rhizosphere whereas NaHCO〈sub〉3〈/sub〉− and NaOH-Pi increased more in ME rhizosphere than NME rhizosphere, irrespective of growth periods. Soil acid and alkaline phosphatases, phosphodiesterase and phytase activities of the ME significantly increased with manure rates up to 75 g kg〈sup〉−1〈/sup〉. Higher enzymatic activities were observed in poultry manure soil than the control and in the rhizospheric soil than bulk soil. The ME showed significantly greater activities of rhizospheric acid phosphatase and phytase than the NME in poultry manure soil at 8 weeks, when its P accumulation showed the largest increase. Therefore, the ME can extract much greater P than the NME from poultry manure-amended soil, probably through the changes in its rhizosphere properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Jessica Badenhorst, Jackie Dabrowski, Clarke H. Scholtz, Wayne F. Truter〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mining activities contribute greatly to economic growth and development in South Africa. However, post-mining soils have limited land-use potential due to low fertility, deficiency in organic matter content and poor physical, chemical, and microbiological properties. Dung beetles could potentially improve several aspects of soil degradation, complementing current rehabilitation efforts. Studies in relatively undisturbed soils of agro-ecosystems have found that dung burial introduces essential nutrients in dung to the plant root zone, which would otherwise remain on the soil surface and mostly volatilize in the absence of dung beetles. Furthermore, dung beetles create tunnels under dung pats, improving water infiltration rates, bulk density, soil aeration and pasture yields. The aim of the study was to determine whether these effects could be maintained on soil simulating reclaimed mined land, where very high rates of compaction may prevent tunnelling altogether. Three experimental treatments of dung + beetles (D + B), dung only (D) and control/no dung, no dung beetles (X) were applied twice over 2 years on 1 m〈sup〉3〈/sup〉 experimental confinements. Various soil and herbaceous plant properties were assessed one and six months after each application of dung and beetles. Results obtained showed that water infiltration rate and plant biomass was significantly higher for all confinements containing dung beetles. Penetration resistance (soil strength) was significantly reduced for confinements with dung beetles. Magnesium and potassium levels in the soil were significantly higher for D + B treatments when compared to D and X treatments. In conclusion, results showed that dung beetles were able to maintain their activities in soils typical of reclaimed mine land, significantly improving soil properties and herbaceous plant growth. Incorporating the application of dung beetles to the conventional approach to rehabilitation has the potential to improve the efficacy of coal mine reclamation. This biological approach may also prove to be cost-effective over time as it provides a seasonal source of bioturbation, which does not disturb plant growth and reduces the requirements for soil rejuvenating tillage practices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Joshua Fanning, Katherine Linsell, Alan McKay, Beverley Gogel, Isabel Munoz Santa, Rowena Davey, Grant Hollaway〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The root lesion nematodes (RLN) 〈em〉Pratylenchus thornei〈/em〉 and 〈em〉P. neglectus〈/em〉 cause yield losses in intolerant field crops, internationally. They both have wide host ranges, invading grass and broadleaf grain crops, pasture species and weeds. Plant resistance, the ability of the plant to prevent nematode reproduction, is the main method of control, but requires accurate information on varietal resistance rankings to plan effective management strategies. This study used a multi environment trial (MET) analysis to examine the effect of cereal varieties (wheat, durum, barley and triticale) on the multiplication of 〈em〉P. thornei〈/em〉 and 〈em〉P. neglectus〈/em〉 when grown in a range of field environments at high and low pre-sowing nematode densities across a range of growing years. The study measured multiplication of 〈em〉P. thornei〈/em〉 (68 varieties) and 〈em〉P. neglectus〈/em〉 (62 varieties) in six and seven field experiments, respectively, each with high and low pre-sowing nematode densities, conducted during the years 2011–2014. This study showed genetic variation in the resistance ranking between cereal types and varieties for both 〈em〉P. thornei〈/em〉 and 〈em〉P. neglectus〈/em〉. This provides management options to growers and information to breeding programs, which can be used to improve the resistance of future varieties. The consistent rankings across the field experiments and observed high genetic correlation between environments was unexpected given experiments were conducted across a range of years, soil types, geographic locations and different pre-sowing nematode densities. These high correlations suggested that varietal resistance can be determined with small numbers of field experiments, thus reducing the costs and time taken to determine varietal resistance. Finally, it was found that a lower pre-sowing nematode density resulted in a higher nematode multiplication rate compared to the high pre-sowing nematode density. This highlights the need to select resistant varieties to avoid large increases in nematode densities in fields with low nematode densities. This analysis of field experimental data for nematodes is novel and indicates that field data can be used to accurately assess varietal resistance (nematode multiplication) across environments. Therefore, accurate data on varietal resistance that is applicable over wide area can be produced with fewer experiments, resulting in varieties with increased resistance being planted, thus reducing grain yield losses due to root lesion nematodes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Minna Santalahti, Hui Sun, Outi-Maaria Sietiö, Kajar Köster, Frank Berninger, Tuomas Laurila, Jukka Pumpanen, Jussi Heinonsalo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reindeer grazing in northern boreal zone affects forest floor vegetation heavily and alters the vegetation structure. However, the effect of grazing on soil fungal communities, which are intimately linked to plants, is not currently known. Therefore, our objectives were to investigate changes caused by reindeer grazing on soil fungal communities, litter decomposition rate and litter degrading extracellular enzyme activities. The study was conducted in four areas divided into grazed and non-grazed sites (all together 38 sample plots) in northern boreal forests in Finnish Lapland. Fungal communities were analyzed from humus with high-throughput sequencing technology (454-pyrosequencing), and litter mass loss and extracellular enzyme activities were analyzed after a one-year litterbag experiment. The results showed that grazing significantly affected the fungal community structure and the abundance of certain fungal genera and species. Grazing also decreased laccase and enhanced cellobiohydrolase I activities from the litterbags. Our study is one of the first to describe detailed fungal community composition in sites with long-term history of reindeer grazing and exclusion. Our results indicate that reindeer grazing alter fungal community structure and litter degradation related enzyme activities in the northern boreal forest soils.〈/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-S0929139317312301-ga1.jpg" width="299" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Deniz Uzman, Jasmin Pliester, Ilona Leyer, Martin H. Entling, Annette Reineke〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Entomopathogenic fungi (EPF) are important antagonists of soil-dwelling insect pests adapted to living in agricultural soils. Little is known about EPF in vineyards, where they could be effective against soil-borne pests such as grapevine phylloxera or larvae of the June beetle. However, the high frequency of fungicide applications might reduce the effectiveness of EPF in vineyard soils. We compared effects of organic and conventional management, fungicide applications and soil parameters on natural occurrence of EPF in vineyards. In 15 pairs of organic and conventional vineyards in Germany, soil was sampled and tested for EPF with a baiting method and subsequent genetic identification. A set of plant protection and soil parameters were measured per site. Three taxa could be verified with 〈em〉Metarhizium〈/em〉 being the most abundant one. Presence of EPF in general and of 〈em〉Metarhizium〈/em〉 spp〈em〉.〈/em〉 was enhanced by a high C:N-ratio. Differences between management systems were minor, with 〈em〉Metarhizium〈/em〉 spp〈em〉.〈/em〉 being more abundant in conventional vineyards. We could not detect a negative effect of fungicides on the presence of EPF. 〈em〉Metarhizium〈/em〉 spp. was more frequently detected with increasing copper content of vineyard soils. We conclude that EPF are able to persist even in intensively managed vineyard systems. Thus, it would be worthwhile to further explore their potential for the biological control of vineyard pests.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Antje Ehrle, Karin Potthast, Alexander Tischer, Susan E. Trumbore, Beate Michalzik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Yellow meadow ant (〈em〉Lasius flavus〈/em〉) mound building activity alters the physico-chemical properties of grassland soils. In this study, 〈em〉L. flavus〈/em〉 mediated changes were assessed along vegetation and soil type differences within four plots located on two study sites. Fine soil, cold- (readily soluble) and hot-water extractable (labile) organic matter (OM) and nutrient fractions of four 〈em〉L. flavus〈/em〉 mounds (0–5 cm and 5–10 cm sampling depth) and four control locations (0–5 cm sampling depth) each, were quantified. All three fractions were further assessed in the horizons of each soil type and complemented by measures of aboveground biomass and vegetation indices related to plant species and composition (Ellenberg indicator values, Shannon-Diversity and Evenness).〈/p〉 〈p〉The surface area covered by 〈em〉L. flavus〈/em〉 mounds and mound density exhibited site and plot related differences, attributed to differences in the soil moisture and -fertility regime, as well as to aboveground biomass. The mound building activity led to a depletion of fine soil, readily soluble and labile OM and sulfur stocks, while mineral-derived fine soil nutrient stocks (calcium (Ca), magnesium, potassium, iron and phosphorous) were higher in the mounds. Effects of 〈em〉L. flavus〈/em〉 activity were most pronounced in a Haplic Stagnosol and an Umbric Leptosol (calcaric), possibly due to stronger contrasts between topsoil and subsoil OM, as well as lower Ca stocks in comparison to the other soils (Stagnic Luvisol and Stagnic Leptosol).〈/p〉 〈p〉This interplay of nutrient depletion and enrichment introduced through the bioturbation by 〈em〉L. flavus〈/em〉, may create a topsoil providing suitable habitat conditions for the establishment of plant species adapted to poor organic nutrient availability. Thus, promoting and preserving 〈em〉L. flavus〈/em〉 mounds may be an important tool to establish resource heterogeneity and hence floral diversity in Central European grasslands.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Xiaohan Xu, Baoshan Yang, Hui Wang, Yanan Cao, Kang Li, Shengwen Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil heterotrophic respiration was profoundly correlated with the decomposition of soil organic carbon and the global carbon balance. It was liable to be affected by temperature and carbon substrate availability. To investigate the effects of different carbon substrate inputs on organic carbon decomposition and the temperature sensitivity of soil heterotrophic respiration along the forest stand ages, we sampled surface soils (0–20 cm) from three 〈em〉Quercus Mongolica〈/em〉 forest stands (20, 30 and 40 years old) in Northeast China. The microcosms were established to incubate the soil under three carbon substrate treatments (glucose, amylopectin, and the combination of glucose and amylopectin) at 13, 23, and 33 °C, respectively. The carbon substrates were 320 μmol g〈sup〉−1〈/sup〉 and 40 μmol g〈sup〉−1〈/sup〉 fresh soil for glucose and amylopectin, respectively. The combined treatment was 160 μmol glucose g〈sup〉−1〈/sup〉 and 20 μmol amylopectin g〈sup〉−1〈/sup〉 fresh soil. The results showed that rates of basal respiration (BR), substrate-induced respiration (SIR), and specific growth rate (SGR) significantly increased with the increasing forest ages. After the addition of carbon substrates, the stimulation effects of SIR and SGR were higher at 23 °C than 13 °C and 33 °C, especially the addition of amylopectin. The Q〈sub〉10〈/sub〉 values of SIR were lower after the addition of glucose than those of amylopectin at lower temperature intervals (13–23 °C), but higher at higher temperatures (23–33 °C). The Q〈sub〉10〈/sub〉 linearly increased with increasing rates of substrate availability. The Q〈sub〉10〈/sub〉 values of SIR stimulated by amylopectin were higher at lower temperature intervals (13–23 °C), suggesting the responses of Q〈sub〉10〈/sub〉 were not only adjusted by carbon substrates but also the ranges of temperature change. The exogenous stable organic carbon inputs greatly increased the Q〈sub〉10〈/sub〉 values of soil heterotrophic respiration in the older forest stands. These results indicated that the decomposition of stable carbon substrate will be more sensitivity to temperature in boreal successional 〈em〉Quercus Mongolica〈/em〉 forest.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Terry J. Torres-Cruz, Cedar Hesse, Cheryl R. Kuske, Andrea Porras-Alfaro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Natural soils represent a rich reservoir of novel and diverse microbial communities. Heavy metal tolerant fungi have been described in contaminated soils and water, but it is unknown how abundant and diverse they are in natural systems. We isolated and identified heavy metal tolerant fungi from a temperate pine forest (Duke Forest, NC, USA) and determined their soil abundance and distribution using amplicon sequencing. Soil serial dilutions were inoculated on malt extract agar with metal concentrations between 100 and 1000 ppm of FeSO〈sub〉4〈/sub〉, ZnSO〈sub〉4〈/sub〉, CuSO〈sub〉4〈/sub〉, Al〈sub〉2〈/sub〉(SO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉, Pb(NO〈sub〉3〈/sub〉)〈sub〉2〈/sub〉, NiCl〈sub〉2〈/sub〉, CdCl〈sub〉2〈/sub〉, and K〈sub〉2〈/sub〉Cr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉, depending on the metal used, at 25 °C. A total of 425 fungal isolates were obtained, from which the majority were isolated in Pb enriched-medium and the least from Cr and Al enriched media. A total of 62 unique Operational Taxonomic Units (OTUs) were identified at 97% sequence similarity using the ITS nuclear ribosomal RNA. The most common and diverse genera isolated were 〈em〉Penicillium〈/em〉 and 〈em〉Trichoderma〈/em〉, with 126 and 92 isolates, representing 10 and 6 unique OTUs, respectively. 〈em〉Umbelopsis, Pochonia, Pseudogymnoascus, Trichocladium,〈/em〉 and 〈em〉Ilyonectria〈/em〉 are reported for the first time as tolerant taxa to multiple metals. The use of culture-based methods also revealed the presence of taxa that could not be detected using soil amplicon sequencing; these non-detectable OTUs corresponded to cultures with low isolation rates. The most commonly isolated taxa were detected using amplicon sequencing in 90–100% of the soil samples and soil depths using direct sequencing techniques, showing consistent results with the cultured-based methods. 〈em〉Penicillium〈/em〉, 〈em〉Trichoderma, Umbelopsis〈/em〉, and 〈em〉Saitozyma〈/em〉 sequences were detected in 100% of the soil samples (156 samples) at all soil depths. Our study shows that this natural environment contained abundant and diverse communities of heavy metal tolerant fungi similar to those reported in metal contaminated sites. These commonly recovered taxa showed wide levels of adaptation to different metals and toxicity levels. The combination of culture-based and direct sequencing approaches were useful to describe the abundance and distribution of heavy metal tolerant fungi in natural soils.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Lucio Valetti, Liliana Iriarte, Adriana Fabra〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Inoculation of microorganisms to improve crop yields and minimize the use of chemical fertilizers is a promising sustainable strategy. The objective of this study was to isolate and identify bacteria from the rhizosphere of rapeseed plants able to solubilize phosphate and promote the growth of this crop. We isolated 40 different bacterial morphotypes which were phenotypically and genotypically characterized. Fourteen isolates (37.8%) were able to solubilize phosphate, 9 of them being epiphytic and 5 endophytic. In greenhouse experiments 7 of these isolates increased shoot dry weight, reaching values similar to those of fertilized plants. Additionally, we determined that survival, growth and biofilm formation ability of these bacteria were not affected by rapeseed root exudates. All the phosphate solubilizing strains able to promote plant growth under greenhouse conditions, with the exception of 〈em〉Bacillus〈/em〉 sp. LTAD-52, also increase rapeseed yield (from 21 to 44%) in field trials.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 131〈/p〉 〈p〉Author(s): Andres Fuentes-Ramirez, Marcia Barrientos, Leonardo Almonacid, Cesar Arriagada-Escamilla, Christian Salas-Eljatib〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil contains a wide variety of microorganisms that are responsible for fundamental ecological processes. However, increased frequency and severity of fires reduce microbial diversity and alter soil nutrient availability, affecting vegetation recovery. By using a large-scale wildfire that burned endangered 〈em〉Araucaria araucana〈/em〉 forests in south-central Chile (38°S), we assessed the short-term post-fire response of microorganisms, soil nutrients, and plant recovery. One year after fire, we sampled soils from burned and unburned areas, and measured the number of bacterial and fungal colony forming units, and the microbiological activity of the soil. We also measured soil nutrients (N, P, and K), organic matter content and species richness, abundance and plant diversity after fire. We found a significant increase in microbiological activity in burned soils (BS) compared to unburned soils (UBS), with bacteria and fungi being four and seven times greater in BS than in UBS, respectively. Concentrations of N, P and K were also greater in BS than in UBS. Plant species richness was two times higher in unburned than in burned areas, with a drastic reduction of the dominant tree species 〈em〉Araucaria araucana〈/em〉 and 〈em〉Nothofagus pumilio〈/em〉 after fire. The changes in soil properties after fire may be related to organic matter mineralization, the contribution of nutrients from ashes, or due to post-fire conditions (e.g., increased soil temperature after canopy removal by fire). Overall, our study shows a positive, short-term response in soil microorganisms abundance and nutrient content, but a rapid initial reduction of plant diversity of the main dominant tree species in these forest ecosystems after a severe fire. Further research is necessary as vegetation results are only preliminary and they can vary in the short-to-medium term. Our study provides insightful clues to delve into more applied research aimed at the post-fire restoration of the endemic, long-lived 〈em〉Araucaria araucana〈/em〉 forests.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 133〈/p〉 〈p〉Author(s): Rachel E. Rudolph, Inga A. Zasada, Cedar Hesse, Lisa W. DeVetter〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A decline in red raspberry (〈em〉Rubus idaeus〈/em〉) crop longevity has been partially attributed to parasitism by the plant-parasitic nematode 〈em〉Pratylenchus penetrans〈/em〉. Soil fumigation with 1,3-dichloropropene (1,3-D) and chloropicrin is the most common management practice for 〈em〉P. penetrans〈/em〉 in this production system, but the effects are variable and there are strict regulations regarding application; alternatives are needed. A three-year study was conducted in a replanted commercial red raspberry field with a history of 〈em〉P. penetrans〈/em〉 to evaluate brassicaceous seed meal (BSM) soil amendment combined with root inoculum removal (RR) as preplant alternatives to traditional soil fumigation with 1,3-D and chloropicrin. Additionally, the fumigant metam sodium at full and half rates with root removal was evaluated. Treatments were applied once prior to planting and included: BSM at 3.4 t ha〈sup〉−1〈/sup〉 with RR, full rate metam sodium (692 L ha〈sup〉−1〈/sup〉; Max Fum) with RR, half rate metam sodium with RR (Min Fum), and full rate metam sodium without RR (Max Fum–RR; control). Data collected included: 〈em〉P. penetrans〈/em〉 population dynamics in soil and raspberry roots, microbial (bacterial and fungal) communities in soil, raspberry vegetative growth, estimated yield, and fruit total soluble solids (TSS) concentration. Population densities of 〈em〉P. penetrans〈/em〉 in soil and roots were significantly higher in BSM (983–4801 〈em〉P. penetrans〈/em〉 g〈sup〉−1〈/sup〉 of root) than in Max Fum and Max Fum–RR (32–802 and 40–1509 〈em〉P. penetrans〈/em〉 g〈sup〉−1〈/sup〉 of root, respectively) during the first two years of the study. By the end of the study there were no differences in 〈em〉P. penetrans〈/em〉 population densities among the treatments. Root removal did not affect 〈em〉P. penetrans〈/em〉 densities as there were no significant differences between Max Fum and Max Fum–RR. Min Fum was more effective than BSM at reducing 〈em〉P. penetrans〈/em〉 population densities, but not as effective as Max Fum or Max Fum-RR. The only difference among treatments regarding the soil microbial community was observed in the first spring after treatment application, when BSM had a soil bacterial community that differed from the other treatments; this difference did not persist into the next sampling date. The most noticeable differences in bacterial and fungal soil communities were due to season, not treatment. There were no significant differences in raspberry vegetative growth the first summer after planting. Yield or TSS did not differ in the second and third summer after planting. The current data show that Min Fum, BSM amended to soil at this experimental rate, and root removal are not effective in reducing 〈em〉P. penetrans〈/em〉 population densities, but yield and fruit quality are not compromised under the conditions of the experiment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Soil Ecology, Volume 132〈/p〉 〈p〉Author(s): Ramez F. Saad, Ahmad Kobaissi, Xavier Goux, Magdalena Calusinska, Guillaume Echevarria, Petra Kidd, Emile Benizri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Agromining aims to rehabilitate contaminated or natural metal-rich soils (ultramafic soils) by extracting metals of high economic importance, such as nickel (Ni), using hyperaccumulator plants and then to recover these metals for industrial purposes. Ultramafic soils are characterized by low fertility levels and this can limit yields of hyperaccumulators and metal phytoextraction. Here, we characterized the potential benefits for phytoextraction efficiency of co-cropping two plants: a Ni-hyperaccumulator (〈em〉Alyssum murale〈/em〉; 〈em〉Brassicaceae〈/em〉) and a legume (〈em〉Vicia sativa〈/em〉; 〈em〉Fabaceae〈/em〉). A field experiment with 3 replicates was set up in an ultramafic zone in North West Spain. Four treatments were tested: co-cropping (“Co”), fertilized mono-culture (“FMo”), non-fertilized mono-culture (“NFMo”) and bulk soil (“BS”). “FMo” and “Co” treatments increased the biomass yields of 〈em〉A. murale〈/em〉 by 453% and 417% respectively, compared to “NFMo”. “Co” treatment generated 35% and 493% higher Ni-yields than “FMo” and “NFMo”, respectively. Most of the microbial analyses showed that introducing 〈em〉V. sativa〈/em〉 (“Co” treatment) into the cropping system had beneficial effects. “Co” treatment significantly modified the phenotypical structure of bacterial communities and raise the relative abundance of the phylum 〈em〉Bacteroidetes〈/em〉 and reduced that of 〈em〉Actinobacteria〈/em〉. In addition, non-metric multidimensional scaling analysis of the operational taxonomic units (OTUs) showed that “Co” was clearly separate from all other treatments. Thus, this study showed that co-cropping a hyperaccumulator with a legume in Ni-agromining systems not only improves plant biomass and Ni-yields, but also enhanced some soil microbial enzymatic activities. Ameliorating agromining by replacing fertilizers would combine eco-efficient or sustainable metal recovery with soil fertility/quality improvement.〈/p〉〈/div〉 〈/div〉