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Nitrate (NO3-1) leaching from soils results in the lower soil fertility, reduced crop productivity and increased water pollution. The effects of bentonite clay mixed with various nitrogen (N) fertilizers on NO3-1 leaching from sandy soils haven't been extensively studied. Therefore, the present lysimetric study determined NO3-1 leaching from bentonite [0, 2 and 4% (m/m)] treated sandy soil under three N sources (calcium nitrate [Ca(NO3)2], ammonium chloride [NH4Cl], and urea [CO(NH2)2] at the rate of 300 kg N ha-1). Results showed that bentonite markedly reduced NO3-1 release in the leachate, while 4% bentonite retained higher NO3 in the soil. The NO3-1 leaching from sandy soil varied with N sources as Ca(NO3)2 > NH4Cl > (CO(NH2)2. At early stages of leaching, higher concentrations of NO3-1 were detected in leachate with both NH4Cl and Ca(NO3)2, but leaching of NO3-1 increased with urea at later leaching stages. The amount of total NO3-1 retained in soil was conversely related to the amount of NO3-1 in the leachate. This study indicated that soil amendment with bentonite could efficiently mitigate NO3-1 leaching from sandy soil and hence prevent N fertilizer losses and groundwater pollution. [ABSTRACT FROM AUTHOR]

This paper aims to examine the key determinants and efficiency of China's agricultural exports with its 114 importing countries by applying the Stochastic Frontier Analysis (SFA) on an augmented gravity model for the period of 2000–2019. The Poisson Pseudo Maximum Likelihood (PPML) and the fixed effect models were also estimated simultaneously to confirm the robustness of our findings. The results reveal that China's economic size (GDP) and its importing countries, the Belt and Road Initiative (BRI), common border, and the Chinese language positively determine China's agricultural export flows. The results, on the other hand, also reveal that China's agricultural export is adversely influenced by the income (per capita GDP) of China and its trade partners, currency depreciation, distance, and landlocked. On an average account, China has untapped the potential of 51% in its agriculture export with the countries used in this study. We provide policy suggestions as part of our study. [ABSTRACT FROM AUTHOR]

Calcium (Ca) is a macronutrient and works as a modulator to mitigate oxidative stress induced by heavy metals. In this study, we investigated the role of Ca to ameliorate the Cd toxicity in Zea mays L. by modulating the growth, physio-biochemical traits, and cellular antioxidant defense system. Maize genotype Sahiwal-2002 was grown under a controlled glasshouse environment with a day/night temperature of 24 ± 4°C/14 ± 2°C in a complete randomized design with three replications and two Cd levels as (0 and 150 μM) and six regimes of Ca (0, 0.5, 1, 2.5, 5, and 10 mM). Maize seedlings exposed to Cd at 150 μM concentration showed a notable decrease in growth, biomass, anthocyanins, chlorophylls, and antioxidant enzymes activities. A higher level of Cd (150 μM) also caused an upsurge in oxidative damage observed as higher electrolyte leakage (increased membrane permeability), H2O2 production, and MDA accumulation. Supplementation of Ca notably improved growth traits, photosynthetic pigments, cellular antioxidants (APX, POD, and ascorbic acid), anthocyanins, and levels of osmolytes. The significant improvement in the osmolytes (proteins and amino acids), and enzymatic antioxidative defense system enhanced the membrane stability and mitigated the damaging effects of Cd. The present results concluded that exogenously applied Ca potentially improve growth by regulating antioxidants and enabling maize plants to withstand the Cd toxicity. [ABSTRACT FROM AUTHOR]

Microalgal biomass provides a renewable source of biofuels and other green products. However, in order to realize economically viable microalgal biorefinery, strategic identification and utilization of suitable microalgal feedstock is fundamental. Here, a multi-step suboptimal screening strategy was used to target promising microalgae strains from selected freshwaters of the study area. The resulting strains were found to be affiliated to seven closely-related genera of the family Scenedesmaceae, as revealed by both morphologic and molecular characterization. Following initial screening under upper psychrophilic to optimum mesophilic (irregular temperature of 14.1 to 35.9°C) cultivation conditions, superior strains were chosen for further studies. Further cultivation of the selected strains under moderate to extreme mesophilic cultivation conditions (irregular temperature of 25.7 to 42.2°C), yielded up to 74.12 mgL-1day-1, 19.96 mgL-1day-1, 48.56%, 3.34 μg/mL and 1.20 μg/mL, for biomass productivity, lipid productivity, carbohydrate content, pigments content and carotenoids content respectively. These performances were deemed promising compared with some previous, optimum conditions-based reports. Interestingly, the fatty acids profile and the high carotenoids content of the studied strains revealed possible tolerance to the stress caused by the changing suboptimal cultivation conditions. Overall, strains AY1, CM6, LY2 and KL10 were exceptional and may present sustainable, promising feedstock for utilization in large-scale generation of green products, including biodiesel, bioethanol, pigments and dietary supplements. The findings of this study, which exposed promising, eurythermal strains, would expand the current knowledge on the search for promising microalgae strains capable of performing under the largely uncontrolled large-scale cultivation settings. [ABSTRACT FROM AUTHOR]

Functioning of ecosystems depends on the nutrient dynamics across trophic levels, largely mediated by microbial interactions in the soil food web. The present study investigated the use of phosphate solubilizing bacteria (PSB) and poultry manure (PM) for maintaining labile P in the soil for an extensive fertility enhancement and as a substitution of chemical fertilizers. Based on the different P solubilizing capabilities of Bacillus and Pseudomonas, a quadruple consortium of Bacillus subtilis, Bacillus cereus, Bacillus thuringiensis and Pseudomonas fluorescens, and their grazer nematodes (soil free living) supplemented with PM were studied. This study was carried out on the trophic levels of soil communities to assess the growth and availability of P to the wheat plants. Experiment was performed for 90 days. Comparing the unamended and amended predator results showed that nematode addition beyond bacterial treatment substantially increased the net available P by ≈2 times, and alkaline phosphatase (ALP) activity by 3.3 times. These results demonstrated the nematodes association with increasing nutrient availability or P mineralization. The interactive effect of PM as substrate and biological drivers was more noticeable on plant dry biomass (1.6 times) and plant P concentration (3.5times) compared to the similar unamended treatment. It is concluded that the biological drivers significantly enhanced the soil ALP and available P while the substrate and biological drivers enhanced dry biomass and plant P concentration. Bacterivore nematodes enhanced the effect of PSB for P mineralization via microbial loop and could be used for the enhancement of wheat production. [ABSTRACT FROM AUTHOR]