Conservation agriculture based sustainable intensification: Increasing yields and water productivity for smallholders of the Eastern Gangetic Plains

摘要

In the Eastern Gangetic Plains (EGP) region of South Asia cropping systems are predominantly rice-based and comprise rice and non-rice crops (e.g. maize, wheat, lentil, mungbean, jute) in rotation. There are large gaps between potential crop yields and those achieved in fanners' fields, primarily due to poor crop and soil management practices. Increasing climate variability and injudicious use of natural resources, particularly water and soil, mean that cropping systems have little resilience and are showing signs of being unsustainable. We hypothesized that replacing traditional crop rotations, grown under conventional tillage (CT) and with full residue removal, with crops grown under zero tillage (ZT) and with partial or full residue retention would improve both crop and cropping system yields, and reduce crop water demand, thus increasing the water productivity of cropping systems across the EGP. We evaluated four tillage-and-crop-establishment scenarios in three major cropping systems (rice-wheat, RW; rice-maize, RM; rice-lentil, RL) across eight districts of the EGP in 433 farmers' fields between 2015 and 2017. We compared farmers' traditional crop establishment practices (T1) against three scenarios based on the principles of conservation agriculture based sustainable intensification (CASI) and comprising a "partial CAST" option (T2: only non-rice crops grown under CASI management) and two "full CASI" options in which both crops were grown under CASI management; in T3 rice was direct seeded rice (DSR) and in T4 rice was transplanted without prior land preparation such as puddling (UPTR).