Table 1_Long-term conservation agriculture improves water-nutrient-energy nexus in maize-wheat-greengram system of South Asia.docx

Contemporary crop management practices are labor, water, and energy inefficient. Identifying a sustainable, productive, and resource-efficient alternate crop production system to the present crop management system is crucial. A field experiment was conducted to assess the effects of conservation agriculture (CA) on crop growth, productivity, and resource use efficiency under the maize-wheat-greengram system during 9th (2018–19) and 10th (2019–20) years of the study. CA-based bed planting methods such as permanent narrow, broad and flat beds with and without retention of crops residues and 75% and 100% of the recommended dose of nitrogen (N) were compared with conventional tillage (CT) treatment. The permanent broad bed with residue with 100% recommended dose of N (PBB + R + 100N) resulted in 56.0%, 60.0% and 26.5% higher root length density in maize, wheat, and greengram crops, respectively. The PBB + R + 100N registered 31.1% higher system productivity than CT. The partial factor productivity (PFP) of N, P, and K were higher under PBB + R + 75N. The CA-based broad-bed practices registered 10.2 and 18.1% savings of irrigation water application than narrow-bed and flat-bed with residue retention, respectively. The CA-based practices without residue retention obtained significantly higher energy productivity, net energy return, and energy ratio than CT. Adopting the CA practice involving a permanent broad bed with residue using 100% N (PBB + R + 100N) in a maize-wheat-greengram system would be more productive and efficient for nutrients, water, and energy. This study focuses on the potential of CA to improve nutrient, water, and energy security in the maize-wheat-greengram system in South Asia.

当前的作物管理模式存在劳动力、水资源与能源利用效率低下的问题。因此，探索一套可持续、高产能且资源利用高效的新型作物生产体系以替代现有管理模式，具有至关重要的意义。本研究于第9年度（2018–2019年）与第10年度（2019–2020年），在玉米-小麦-绿豆轮作体系下开展田间试验，以评估保护性农业（Conservation Agriculture, CA）对作物生长、产能及资源利用效率的影响。试验对比了多种保护性农业垄作模式：永久窄垄、宽垄与平垄，分别搭配秸秆还田与不还田，并设置75%和100%推荐施氮量（N）处理，同时以传统耕作（Conventional Tillage, CT）作为对照组。结果显示，永久宽垄+秸秆还田+100%推荐施氮量（PBB + R + 100N）处理下，玉米、小麦与绿豆的根长密度分别较对照组提升56.0%、60.0%与26.5%；该处理的体系产能较传统耕作组高出31.1%。PBB + R + 75N处理下，氮、磷、钾的养分偏生产力（Partial Factor Productivity, PFP）均更高。保护性农业宽垄耕作模式的灌溉用水量较带秸秆还田的窄垄和平垄模式分别减少10.2%与18.1%。未实施秸秆还田的保护性农业模式，其能量生产力、净能量收益与能量利用效率均显著高于传统耕作组。在玉米-小麦-绿豆轮作体系中采用永久宽垄+秸秆还田+100%推荐施氮量（PBB + R + 100N）的保护性农业模式，可在养分、水资源与能源利用方面实现更高的产能与利用效率。本研究旨在探讨保护性农业在南亚玉米-小麦-绿豆轮作体系中，对提升养分、水资源与能源安全的应用潜力。