ALBERT

Description: Agronomy, Vol. 8, Pages 203: Biochars Improve Nutrient Phyto-Availability of Hawai’i’s Highly Weathered Soils Agronomy doi: 10.3390/agronomy8100203 Authors: Arnoldus Klau Berek Nguyen V. Hue Theodore J. K. Radovich Amjad A. Ahmad Highly weathered soils in Hawai’i are low in fertility, negatively affecting plant growth. The potential of biochar for improving soil nutrient availability to crops is promising, and prompts this study. Two biochars at 2% (w/w) made of lac tree (Schleichera oleosa (Lour.) Oken) wood and mixed wood (scrapped wood and tree trimmings) with and without vermicompost or thermocompost at 2% (w/w) were added to an Ultisol (Ustic Kanhaplohumult, Leilehua series) and an Oxisol (Rhodic haplustox, Wahiawa series) of Hawai’i. In each soil two additional treatments—lime + compost and un-amended soil—served as the control. Chinese cabbage (Brassica rapa cv. Bonsai) was used as the test plant in two greenhouse plantings, which had a factorial completely randomized design with three replicates per treatment. The results indicated that soil acidity, nutrient in the soils, plant growth and nutrient uptake were improved by the amendments compared to the control. The combined additions of biochar and compost significantly increased pH and EC; reduced exchangeable Al; reduced Mn and Fe in the Oxisol; increased P, K, and Ca content of the soils; and increased Ca, Mg and Fe uptake. Exchangeable aluminum in the Ultisol decreased from 2.5 cmol+/kg to nil; Mehlich-3 extractable P, K, Ca, Mg, Fe, and Mn in the Ultisol increased by 1478%, 2257%, 1457%, 258%, 125% and 72%, respectively compared to the un-amended soil, while the same nutrients increased or decreased in the Oxisol by 180%, 59%, 308%, −14%, and −36%, respectively. Shoot and total cabbage fresh and dry matters increased by 94%, 96%, 107%, and 112%, respectively, as compared to the lime plus compost treatment. Cabbage growth in the Ultisol amended with the lac tree wood biochar and vermicompost was almost twice over the lime and vermicompost treatment. Essential nutrients in the plant tissues, except for N and K, were sufficient for the cabbage growth, suggesting increases in nutrients and reduced soil acidity by the additions of biochar combined with compost were the probable cause. It is recommended that locally produced biochars and composts be used to improve plant nutrient availability in the highly weathered soils.

Description: Climate, Vol. 6, Pages 78: Possible Scenarios of Winter Wheat Yield Reduction of Dryland Qazvin Province, Iran, Based on Prediction of Temperature and Precipitation Till the End of the Century Climate doi: 10.3390/cli6040078 Authors: Behnam Mirgol Meisam Nazari The climate of the Earth is changing. The Earth’s temperature is projected to maintain its upward trend in the next few decades. Temperature and precipitation are two very important factors affecting crop yields, especially in arid and semi-arid regions. There is a need for future climate predictions to protect vulnerable sectors like agriculture in drylands. In this study, the downscaling of two important climatic variables—temperature and precipitation—was done by the CanESM2 and HadCM3 models under five different scenarios for the semi-arid province of Qazvin, located in Iran. The most efficient scenario was selected to predict the dryland winter wheat yield of the province for the three periods: 2010–2039, 2040–2069, and 2070–2099. The results showed that the models are able to satisfactorily predict the daily mean temperature and annual precipitation for the three mentioned periods. Generally, the daily mean temperature and annual precipitation tended to decrease in these periods when compared to the current reference values. However, the scenarios rcp2.6 and B2, respectively, predicted that the precipitation will fall less or even increase in the period 2070–2099. The scenario rcp2.6 seemed to be the most efficient to predict the dryland winter wheat yield of the province for the next few decades. The grain yield is projected to drop considerably over the three periods, especially in the last period, mainly due to the reduction in precipitation in March. This leads us to devise some adaptive strategies to prevent the detrimental impacts of climate change on the dryland winter wheat yield of the province.

Description: Agriculture, Vol. 8, Pages 148: Effect of Harvest Timing and Soil Moisture Content on Compaction, Growth and Harvest Yield in a Miscanthus Cropping System Agriculture doi: 10.3390/agriculture8100148 Authors: Michael G. O’Flynn John M. Finnan Edna M. Curley Kevin P. McDonnell Harvesting Miscanthus × giganteus (J.M. Greef & Deuter ex Hodkinson & Renvoize) after shoot emergence is known to reduce yields in subsequent seasons. This research was conducted in Miscanthus to assess the effects on crop response and soil compaction of annually repeated traffic, applied both before new growth in the rhizomes (early harvest) and after shoot emergence (late harvest), at two different soil moisture contents. While an annual early harvest, yields more than a late harvest, because damage to new shoots is avoided, soil compaction may be increased following repeated harvests. Five treatments were tested: (a) An untrafficked control, (b) early-traffic on soil with typical soil moisture content (SMC) (early-normal), (c) early-traffic on soil with elevated SMC (early-elevated), (d) late-traffic on soil with typical SMC (late-normal) and (e) late-traffic on soil with elevated SMC (late-wet). The experiment was conducted on a Gleysol in Co. Dublin, Ireland during 2010 and 2011. Crop response effects were assessed by measuring stem numbers, stem height, trafficked zone biomass yield (November) and overall stem yield (January). Compaction effects were assessed by measuring penetration resistance, bulk density and water infiltration rate. Trafficked zone biomass yield in the early-dry and early-wet treatments was, respectively, 18% and 23% lower than in the control, but was, respectively, 39% and 31% higher than in the late-dry treatment. Overall, stem yield was significantly lower in the late-normal and late-wet treatments (10.4 and 10.1 tdm ha−1 respectively) when compared with the control (12.4 tdm ha−1), but no significant difference was recorded in overall stem yield between both early-traffic treatments and the control. Penetration resistance values were significantly higher in all trafficked treatments when compared with the control at depths of 0.15 m (≥54–61%) and 0.30 m (≥27–57%) and were significantly higher in 2011 when compared with 2010 at depths of 0.15 and 0.30 m. Baler system traffic in Miscanthus significantly reduced yields and significantly increased compaction annually. Miscanthus harvested early, on a dry soil, yielded 1.1 tdm ha−1 more than when harvested late on a dry soil. The yield advantage increased to 1.3 tdm ha−1 when early harvesting on a soil with 40–43% moisture content was compared with late harvesting on a wetter soil (51–52% moisture content). In this study, the magnitude of yield losses from compaction or other causes in early harvests was substantially lower than the yield losses, which resulted from shoot damage in late harvests. It is likely in similar climates that the results of this study would also apply to other perennial crops growing in similar soil types.

Description: Environments, Vol. 5, Pages 106: Preface: Special Issue on Innovative Processes and Technologies for the Management of Hazardous Waste Environments doi: 10.3390/environments5100106 Authors: Terry Tudor Mentore Vaccari n/a

Description: Agronomy, Vol. 8, Pages 202: Mitigation Potential and Yield-Scaled Global Warming Potential of Early-Season Drainage from a Rice Paddy in Tamil Nadu, India Agronomy doi: 10.3390/agronomy8100202 Authors: Aung Zaw Oo Shigeto Sudo Kazuyuki Inubushi Umamageswari Chellappan Akinori Yamamoto Keitsuke Ono Masayoshi Mano Sachiko Hayashida Vanitha Koothan Takeshi Osawa Yukio Terao Jothimani Palanisamy Elayakumar Palanisamy Ravi Venkatachalam Water-intensive systems of rice cultivation are facing major challenges to increase rice grain yield under conditions of water scarcity while also reducing greenhouse gas (GHG) emissions. The adoption of effective irrigation strategies in the paddy rice system is one of the most promising options for mitigating GHG emissions while maintaining high crop yields. To evaluate the effect of different alternate wetting and drying (AWD) irrigation strategies on GHG emissions from paddy rice in dry and wet seasons, a field experiment was conducted at the Tamil Nadu Rice Research Institute (TRRI), Aduthurai, Tamil Nadu, India. Four irrigation treatments were included: One-AWD (one early drying period), Two-AWD (two early drying periods), Full-AWD (wetting and drying cycles throughout the rice season), and CF (continuous flooding). Different rice varieties were also tested in the experiment. In this study, we emphasized one factor (irrigation effect) that affects the dependent variable. The results show that early AWD treatments reduced methane (CH4) emissions by 35.7 to 51.5% in dry season and 18.5 to 20.1% in wet season, while full-AWD practice reduced CH4 emissions by 52.8 to 61.4% compared with CF. Full-AWD in dry season not only significantly reduced CH4 emission during that season, it also resulted in the decline of the early season emission in the succeeding wet season. Global warming potential (GWP) and yield-scaled GWP were reduced by early or full season AWD in both rice seasons. The GWP value from nitrous oxide (N2O) was relatively low compared to that from CH4 in both rice seasons. Rice yield was not affected by irrigation treatments although varietal differences in grain and straw yields were observed in both rice seasons. This study demonstrated that early season water managements are also effective in reducing CH4 and total GHG emissions without affecting rice yield.

Description: Agronomy, Vol. 8, Pages 199: Forage Warm-Season Legumes and Grasses Intercropped with Corn as an Alternative for Corn Silage Production Agronomy doi: 10.3390/agronomy8100199 Authors: Renata La Guardia Nave Michael Dereck Corbin Intercropping of forage grasses and legumes can increase forage productivity and nutritive value; however, intercropping of corn with warm-season forages has not yet been studied in southeast U.S., thus requiring more information. The purpose of this study was to determine the yield and nutritive value potential of warm-season annual forages intercropped with corn (Zea mays L.) for silage production. Crabgrass [Digitaria sanguinalis (L.)] is considered a weed for corn production systems; however, our study shows that if crabgrass is interseeded with corn, it does not compete for resources and can maintain high corn yields. Forage mass for sunn hemp (Crotalaria juncea L.) was higher than that of cowpea [Vigna unguiculata (L.) Walp.] and crabgrass in 2016, due to a drought in spring and summer, giving sunn hemp a competitive advantage. Crude protein content was higher for cowpea as compared to crabgrass and sunn hemp, due to cowpea’s ability to maintain its vegetative stage and high N-fixation, when compared to crabgrass and sunn hemp. Despite differences in the mass of the intercropped forages, the total herbage mass of the produced silage did not differ in 2016 and 2017. Intercropped forages can be harvested and ensiled with corn for silage production or can be left with the corn residue after harvesting to be grazed on in integrated crop-livestock systems.

Description: Agronomy, Vol. 8, Pages 201: Evaluating Two Crop Circle Active Canopy Sensors for In-Season Diagnosis of Winter Wheat Nitrogen Status Agronomy doi: 10.3390/agronomy8100201 Authors: Qiang Cao Yuxin Miao Jianning Shen Fei Yuan Shanshan Cheng Zhenling Cui Active crop canopy sensors can be used for non-destructive real-time diagnosis of crop nitrogen (N) status and guiding in-season N management. However, limited studies have compared the performances of two commercially available sensors with three different wavebands: Crop Circle ACS-470 (CC-470) and Crop Circle ACS-430 (CC-430). The objective of this study was to evaluate the performances of CC-470 and CC-430 sensors for estimating winter wheat (Triticum aestivum L.) N status at different measurement heights (40 cm, 70 cm and 100 cm) and growth stages. Results indicated that the canopy reflectance values of CC-470 were more affected by height compared to the CC-430 sensor. The normalized difference red edge (NDRE) and red edge chlorophyll index (CIRE) of CC-430 were stable at the three different measuring heights. The relationships between these indices and the N status indicators were stronger at the Feekes 9–10 stages than the Feekes 6–7 stages for both sensors; however, the CC-430 sensor-based vegetation indices had higher coefficient of determination (R2) values for both stages. It is concluded that the CC-430 sensor is more reliable than CC-470 for winter wheat N status estimation due to its capability of making height-independent measurements. These results demonstrated the importance of considering the influences of height when using active canopy sensors in field measurements.

Description: Agronomy, Vol. 8, Pages 200: Can Faba Bean Physiological Responses Stem from Contrasting Traffic Management Regimes? Agronomy doi: 10.3390/agronomy8100200 Authors: Kris G. Guenette Guillermo Hernandez-Ramirez Our study examined how faba beans (Vicia faba L.) grown in soil conditions that simulate common traffic management regimes and water availabilities displayed alterations to their physiological state. Physiological changes were tracked through plant and sensor-based measurements, such as evapotranspiration, water use efficiency, aboveground biomass, stomatal conductance, and normalized difference vegetation index. A greenhouse experiment comprised of faba beans were sown into pots of two different soil types that were separated by treatments of dry bulk density and volumetric water content. The compaction treatment with a bulk density of 1.2 g cm−3 coupled with a volumetric water content of 41% displayed more favorable changes to the physiological state of the faba beans than the contrasting treatment of 1.4 g cm−3 bulk density at 33% volumetric water content. Handheld sensor-based measurements, such as the normalized difference vegetation index, exhibited a strong correlation with faba bean biomass production. Furthermore, the stomatal conductance was able to reveal plant water stress and capture evapotranspiration responses. Conclusive observations showed that increasing soil compaction restricted plant productivity. However, the presence of high water content was shown to offset the negative effects of heavily applied compaction while relatively lower water contents exacerbated differences in plant responses across compaction treatments.

Description: Resources, Vol. 7, Pages 62: Ten Steps Qualitative Modelling: Development and Validation of Conceptual Institutional-Social-Ecological Model of Public Open Space (POS) Governance and Quality Resources doi: 10.3390/resources7040062 Authors: Gabriel Hoh Teck Ling Pau Chung Leng Compared to the literature on quantitative and statistical modelling, there is a lack of research on qualitative environmental-related modelling, which focuses on a conceptual-theory-based model. Therefore, this paper attempts to formulate a qualitative institutional-social-ecological model, by showcasing how the 10 steps modelling is relevant and is applied to the institutional-property-rights model of neighbourhood residential commons. Using an instance from one case study (i.e., Sabah, Malaysia), a conceptual problem-solution model describing local property-rights system tragedies of public open space (POS) governance and quality, and the emergence of self-governing collective action was demonstrated. Methodologically, the modelling procedures were specified as a 10-step process, starting with setting the objectives of the model and concluding with the validation of suitability and usefulness of the model. The validation was conducted using the experts’ opinion, via the semi-structured interviews with five public officials. With slight necessary amendments, the model was proven practical, useful, flexible, reliable and valid in serving its purposes in understanding and predicting the effects of local property-rights system tragedies on POS commons dilemmas, and the subsequent emergence and necessity of a self-governing solution. This local model provides policy insights to the local public officials, which facilitate their institutional-social-ecological decision-making process that helps improve local POS governance and quality.

Description: Resources, Vol. 7, Pages 60: Fermentable Sugar Production from the Peels of Two Durian (Durio zibethinus Murr.) Cultivars by Phosphoric Acid Pretreatment Resources doi: 10.3390/resources7040060 Authors: Abraham Kusi Obeng Duangporn Premjet Siripong Premjet The potential of durian (Durio zibethinus Murr.) peel as feedstock for the production of fermentable sugars was evaluated. Durian peel biomass from two cultivars, monthong (Durio zibethinus Murr. cv. Monthong) and chanee (Durio zibethinus Murr. cv. Chanee), were pretreated with different concentrations (70%, 75%, 80%, and 85%) of phosphoric acid (H3PO4) at a moderate temperature of 60 °C for 60 min. The H3PO4-pretreated durian peel biomass was then subjected to enzymatic hydrolysis. Significantly higher glucan (44.74 ± 0.21%) content was observed in the monthong peel compared to the chanee peel (42.06 ± 0.28%). Phosphoric acid pretreatment caused the significant solubilization of the xylan and acid soluble lignin (ASL) contents. This enhanced the enzymatic hydrolysis process causing a significant increase in the hydrolysis efficiency and glucose concentration. The highest hydrolysis efficiency and glucose concentration were obtained after 72 h from the 75% H3PO4-pretreated peel biomass for both the monthong (90.33 ± 0.42% and 9.55 ± 0.11 g/L, respectively) and chanee (90.06 ± 0.40% and 8.56 ± 0.13 g/L, respectively) peels. Biomass to glucose recovery for monthong and chanee were improved by approximately 7- and 6-fold, respectively. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis showed destruction of the peel biomass structure and changes in the cellulose crystallinity index (CrIs).