Effect of Conservation Agriculture Production Systems (CAPS) on System Productivity, Soil Quality and Sustainability under Rainfed Uplands of India

Abstract

Traditional agriculture in rainfed uplands of India is increasingly relegated to low crop yield as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift towards more sustainable cropping systems such as conservation agriculture production systems (CAPS) may help in maintaining soil quality as well as improving crop production and farmer’s net economic benefit. Because conservation agriculture may take a decade or longer to realize the full benefits, there is a need to identify shorter-term indicators in order to assess performance and techno-economic feasibility of CAPS before making long-term recommendations. This research assessed the effects of CAPS practices in upland areas of Odisha, India. Reduced tillage, intercropping, and cover cropping were explored singly and in combination at a research station over three years. The first study focused on crop yield, system productivity and profitability through a) maize equivalent yield, and b) dominance analysis. Results showed that minimum tillage combined with maize-cowpea intercropping followed by mustard residue retention had higher system productivity and net benefits over traditional system. The second study assessed soil quality by calculating an index composed of measurements of physical, chemical and biological properties. It was found that among measured soil parameters, water stable macro-aggregates, labile carbon (C), total soil nitrogen (N), C: N, extractable nitrate, and potentially mineralizable nitrogen best reflected changes due to CAPS. The soil quality index was highest under minimum tillage combined with maize cropping followed by horse gram residue retention. Finally, the effect of CAPS on soil organic matter pools was assessed through a fractionation procedure combining size and density. The light particulate organic matter (POM) fraction was the most sensitive to CAPS with its greatest increase under mustard residue retention. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these CAPS should be acceptable and attractive for smallholder farmers in the area. Moreover, the ability to simultaneously increase yield, diversify crop production and improve soil quality should support a move towards sustainable crop intensification to meet future household income and nutritional needs.