Conservation agriculture effects on soil properties and crop productivity in a semiarid region of India

Conservation agriculture (CA) including reduced or no-tillage and crop residue retention, is known to be a self-sustainable system as well as an alternative to residue burning. The present study evaluated the effect of reduced tillage coupled with residue retention under different cropping systems on soil properties and crop yields in a Vertisol of a semiarid region of central India. Two tillage systems-conventional tillage (CT) with residue removed, and reduced tillage (RT) with residue retained-and six major cropping systems of this region were examined after 3 years of experimentation. Results demonstrated that soil moisture content, mean weight diameter, percent water stable aggregates (> 0.25 mm) for the 0-15 cm soil layer were significantly (P < 0.05) affected by tillage practices. Soil penetration resistance was significantly higher for RT than CT. Irrespective of soil depth, there was higher soil organic carbon (SOC) for RT than CT. The SOC fractions followed in the order: non-labile > moderately labile > less labile. At the 0-15 cm depth, the contributions of moderately labile, less labile and non-labile C fractions to total organic C were 39.3%, 10.3% and 50.4% respectively in RT and corresponding values for CT were 38.9%, 11.7% and 49.4%. Significant differences in different C fractions were observed between RT and CT. Soil microbial biomass C concentration was significantly higher in RT than CT at 0-15 cm depth. The maize-chickpea cropping system had significantly (P < 0.05) higher soybean grain equivalent yield of 4.65 t ha(-1) followed by soybean + pigeon pea (2 : 1) intercropping (3.50 t ha(-1)) and soybean-wheat cropping systems (2.97 t ha(-1)). Thus, CA practices could be sustainable management practices for improving soil health and crop yields of rainfed Vertisols in these semiarid regions.