Effects of Tillage, Residue and Fertilizer Nitrogen on Crop Yields, and Soil Physical Properties Under Soybean-Wheat Rotation in Vertisols of Central India

Soybean-wheat cropping system is predominant in vertisols of central India. Long-term field experiment was conducted to assess the effect of four tillage systems [conventional tillage (CT), mouldboard tillage (MB), reduced tillage (RT) and no tillage (NT)] and three rates of fertilizer N (50, 100 and 150 % of recommended fertilizer) on crop yields, root growth, soil organic carbon (SOC) content and physical properties in soybean-wheat cropping system. Productivity of soybean and wheat was similar in different tillage systems. Response of fertilizer N was not influenced by tillage systems, and crop response to fertilizer N was generally observed up to 100 % of the recommended N fertilizer. Root length density of soybean in the top 15 cm depth was higher in NT and RT than in MB and CT. An improvement in selected soil physical properties like soil water storage, bulk density, aggregate stability and saturated hydraulic conductivity (Ks) was recorded in NT and RT than in CT. SOC content at 0-15 cm depth was significantly higher in NT, RT and MB where wheat residues were retained after harvest than that in CT system. The SOC, aggregate stability and Ks were significantly higher in N-150 % compared to N-50 %. It is concluded that no tillage and reduced tillage systems with residue retention and recommended rate of N would be a suitable practice for sustainable production of soybean-wheat cropping system in vertisols of central India.