Potential Productivity, Yield Gap, and Water Balance of Soybean-Chickpea Sequential System at Selected Benchmark Sites in India.Global Theme 3: Water, Soil, and Agrobiodiversity Management for Ecosystem Health Report No.1

ICRISAT’s intervention in the project “Improving Management of Natural Resources for Sustainable Rainfed Agriculture” funded by the Asian Development Bank aims to increase the productivity and sustainability of the medium and high water-holding capacity soils in the intermediate rainfall ecoregion of India, Thailand, and Vietnam. Soybean is the predominant crop in the target region of India and has the potential to be followed by chickpea crop on a larger scale in the postrainy season. Using the CROPGRO models of soybean and chickpea, this study examined the potential yields, yield gap, and water balance of the soybean-chickpea sequential system for the 24 selected benchmark sites within the soybean production zones of India. Considering the variability in soils and climate, this simulation study showed that the average potential productivity of the soybean-chickpea system under rainfed situation ranged from 1390 to 4590 kg ha-1 across sites. The current level of productivity of the system across sites ranges from 970 to 1780 kg ha-1. The yield gap of 200 to 3300 kg ha-1 for the system indicate the potential to increase productivity with improved management under rainfed situation. However, higher increases in yields would be possible in good rainfall years or with supplemental irrigation. Water balance analysis showed that on an average 35 to 70% of rainfall was used by the crop as evapotranspiration, whereas 25 to 40% was lost as surface runoff indicating the need for water harvesting for supplemental irrigation or to recharge the groundwater in the target region. Various constraints limiting crop yields in these regions have been highlighted. It is suggested that location-specific integrated approaches would be needed to bridge the yield gap of the predominant crops grown in the target regions.