Search

The determination of changes in soil organic carbon (SOC) content under different cropping systems is necessary for policy development oriented towards soil conservation, C sequestration, and future C credit markets. The aim of this study was to generate an open SOC dataset resulting from a systematic literature search related to the agricultural systems for Southeast Asia. The dataset has 209 articles and 4341 observations on soils of cropping systems in this region from articles published between 1987 and 2023. This dataset included different management practices, land uses, soil sampling depth, and length of SOC content assessment. In addition, inherent features of crop production reported in the experiments were included in the dataset. This dataset can be applied to quantify and compare the impact of different land uses or management practices on SOC content, providing foundational knowledge towards identifying sustainable practices. Lastly, it is a useful guide for future regional SOC sequestration policies and the development of C credit markets.

Crop nitrogen (N) fertilization diagnoses via the N nutrition index (NNI)-yield relationship have been tested for several crop species, but a cross-species comparison of that relationship has not been performed yet. This study aimed to perform a cross-species comparison of the relationship between NNI and yield with emphasis on the yield sensitivity to N deficiency, slope of the models. Additionally, we conducted an evaluation to determine the best NNI sampling moment to predict relative yield, with focus on major grain crops. Based on a recently published global dataset to parametrize critical dilution curves, we calculated integrated NNI, instantaneous NNI, relative yield, and relative shoot biomass for annual ryegrass, tall fescue, maize, potato, rice, and wheat. We obtained 238 observations to fit integrated NNI-relative yield linear mixed-effects models and 1606 observations to fit instantaneous NNI-relative yield models. Subsequently, we performed a sensitivity analysis to determine the best NNI sampling moment to predict relative yield, with focus on major grain crops (maize, rice, and wheat). Our results show that there was low inter-species variation of sensitivity to N deficiency, i.e., the slope of the relationship between relative yield and integrated NNI. For grain crops, instantaneous NNI around anthesis demonstrated a better predictive capability for relative yield, outperforming other vegetative stages. This finding contributed to improving the understanding of the association between relative yield and NNI with implications for breeding programs, nutrient management practices, and crop modelling. Most importantly, this study is a contribution to improving the N nutrition diagnosis for several crop species, by using an integral, comparative approach.

Hydrogen-uptake (Hup) activity is implicated in the mitigation of energy losses associated with the biological nitrogen fixation process, and has been related to productivity increases in some legume hosts. However, in common bean (Phaseolus vulgaris L.) the expression of hydrogenase is rare. In this study an 18-kb hup gene cluster from Rhizobium leguminosarum bv. viciae encoding a NiFe hydrogenase was successfully transferred to three common bean rhizobial strains lacking hydrogenase activity (Hup-) but symbiotically very effective and used in commercial inoculants in Brazil: one strain originally from Colombia (Rhizobium tropici CIAT 899), and two strains from Brazil (R. tropici H 12 and Rhizobium freirei PRF 81). The inclusion of NiCl2 in the nutrient solution did not increase hydrogenase activity, indicating that common bean plants allow efficient nickel provision for hydrogenase synthesis in the bacteroids. The symbiotic performance-evaluated by nodulation, plant growth, N accumulation and seed production-of wild-type and Hup+ derivative strains was compared in experiments performed with cultivar Carioca under greenhouse conditions, in sterile substrate and in non-sterile soil. Statistically significant increases in one or more parameters were observed for all three Hup+ derivatives when compared to the respective wild-type strain. Differences were found mainly with the Brazilian strains, reaching impressive increases in nodule efficiency and seed total N content. The results highlight the potential of using Rhizobium Hup+ strains for the design of more energy-efficient inoculants for the common bean crop.

Sorghum is an important crop that serve multiple purposes as human food, animal feed, and bioenergy production. There are opportunities to produce different types of biofuels from sorghum-based biomass. Sorghum with its vast genetic resources can serve as bioenergy crop and not compete against the value of it as food and nutritional security crop. Bioenegy crops provides an opportunity for agriculture to be part of solution for energy and mitigation to climate change. This review provides detailed overview and current knowledge on the conversion of sorghum biomass (stalks, leaves, and grains) into liquid (bioethanol, biodiesel, and bio-oil), gas (biohydrogen, biogas, and syngas) and solid (biochar) biofuels. Progress made in the different sorghum-based biomass pretreatment and conversion processes including chemical, biochemical, thermochemical and biological processes (e.g. saccharification, fermentation, transesterification, hydrothermal liquefaction, pyrolysis, and gasification) are highlighted and described. In addition, several value-added products from sorghum gaining importance in biofuels production are summarized. Finally, the potential outlook on sorghum based biorefiners and potential for improving sorghum-based biofuel production is presented and discussed. The biorefinery concept offers a considerable scope for optimization of sorghum biomass utilization to produce biofuels and biochemicals. However, there is further need to clearly identify the best methods of pre-treatment, processing, and products from different sources. Sorghum with its high biomass production and multiple use has the potential to be key biofuel crop. Further research is needed to identify most efficient and cost effective processes to ensure the value of biofuel and other bioproducts from sorghum. A complete lifecycle analyses indicating the challenges and opportunities to enhance the efficiency, benefits, and challenges in different steps and finding solutions to overcome those ch

Among the minor coarse grains cultivated in the world, barley leads the area under cultivation, followed by oats and others. This chapter discusses growth stages, climatic requirements, and management practices of oat, barley, and minor millets. Winter oat varieties take approximately 12 d from sowing to emergence, 267 d from sowing to anthesis, and 58 d from anthesis to harvest. After seed germination, shoot growth of barley is dependent on the activity of the shoot apical meristem, which produces the internode, leaf, and axillary bud. Barley can be grown as a summer or winter crop. The ideal pH for spring barley is 6.5. This ensures optimum availability of both macro- and micro-nutrients. Minor millets mature in the range of 85 to 130 d after sowing. Generally, the growth stages of millets can be classified into three distinct stages, namely vegetative, pre- and post-flowering stages.

Excitement is high about the potential uses of unmanned aerial systems (UAS) in agriculture. We budgeted the costs of high-yield, non-irrigated corn production on two fields on a “representative” farm located in Northeastern Kansas. One complete pass over each field was completed. The representative farm will use a manned aerial system (MAS) or UAS and visual inspection and soil/tissue tests to determine whether and where a nitrogen deficiency is occurring. Our analysis suggests that UAS is less costly than MAS. The authors expect the costs of UAS and MAS to decrease in the future.

Excitement is high about the potential uses of unmanned aerial systems (UAS) in agriculture. We budgeted the costs of high-yield, non-irrigated corn production on two fields on a “representative” farm located in Northeastern Kansas. One complete pass over each field was completed. The representative farm will use a manned aerial system (MAS) or UAS and visual inspection and soil/tissue tests to determine whether and where a nitrogen deficiency is occurring. Our analysis suggests that UAS is less costly than MAS. The authors expect the costs of UAS and MAS to decrease in the future.

Describes knowledge of how environmental conditions and pests affect growth of soybean crops during vegetative and reproductive stages in order to direct proper crop management.