Potential Productivity, Yield Gap, and Water Balance of Soybean-Chickpea Sequential Systematic Selected Benchmark Sites in India

Before any improvements to crop management practices are made, it is useful to know the potential yield of crops in the region of interest, and the gap between the potential yield and the actual yield obtained by the growers. This analysis helps to know the major factors causing the difference between the actual and the attainable yield for a given site. Under the Asian Development Bank (ADB)-supported project on integrated watershed management we carried out such analysis for soybean-chickpea sequential system for the regions where the project is operational. We used CROPGRO models of soybean and chickpea to determine the yield potential (water-limited yields) and yield gap of the two crops for several sites within the soybean production zones of India. The simulation study showed that the average potential productivity of the soybean-chickpea sequential 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 indicates 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 35 to 70 % of rainfall was used by the crop as evapotranspiration