Strategic double cropping on Vertisols: A viable rainfed cropping option in the Indian SAT to increase productivity and reduce risk uri icon

abstract

  • Our study suggests the possibility for transformational change in the productivity and risk profile of some of India's rainfed cropping systems. In the semi-arid regions of Southern India, farmers traditionally crop sorghum or chickpea on Vertisols during the post-rainy season, keeping the fields fallow during the rainy season. This practice avoids land management problems, but limits the potential for crop intensification to increase systems productivity. A long-term (15 year) experiment at ICRISAT demonstrated that cropping during the rainy season is technically feasible, and that grain productivity of double cropped sorghum + chickpea (SCP?SCP) and mung bean + sorghum (MS?MS) sequential systems were higher than their conventional counterparts with rainy season fallow, i.e. fallow + post-rainy sorghum (FS?FS) and fallow + post-rainy chickpea (FS?FCP). Without N application, mean grain yield of post-rainy sorghum in the MS?MS system was significantly greater (2520 kg ha?1 per two-year rotation) than in the FS?FS system (1940 kg ha?1 per two-year rotation), with the added benefit of the mung bean grain yield (1000 kg ha?1 per two-year rotation) from the MS?MS system. In the SCP?SCP system the additional grain yield of rainy sorghum (3400 kg ha?1 per two-year rotation) ensured that the total productivity of this system was greater than all other systems. Double cropping MS?MS and SCP?SCP sequential systems had significantly higher crop N uptake compared to traditional fallow systems at all rates of applied nitrogen(N). The intensified MS?MS and SCP?SCP sequential systems without any N fertilizer applied recorded a much higher median gross profit of Rs. 20,600 (US $ 375) and Rs. 15,930 (US $ 290) ha?1 yr?1, respectively, compared to Rs. 1560 (US $ 28) ha?1 yr?1) with the FS?FS system. Applying 120 kg of N ha?1 considerably increased the profitability of all systems, lifting median gross profits of the sorghum + chickpea system over Rs. 60,000 (US $ 1091) ha?1 yr?1 and the conventional system to Rs. 20,570 (US $ 374) ha?1 yr?1. The gross profit margin analysis showed that nitrogen is a key input for improving productivity, particularly for the double cropping systems. However, traditional systems are unviable and risky without N application in the variable climates of the semi-arid tropics. Together, our results show that on Vertisols in semi-arid India, double cropping systems increase systems? productivity, and are financially more profitability and less risky than traditional fallow post-rainy systems while further benefits can be achieved through fertilizer application

publication date

  • 2015
  • 2015