Effect of Conservation Agricultural Practices on Crop Yield and Soil Properties Under Sorghum [Sorghum bicolor (L.) Moench] - Black Gram [Vigna mungo (L.) Hepper] System in Rainfed Alfisol

A long-term study was conducted to assess the effect of tillage (conventional, CT and minimum, MT) and residue retention treatments on crop yields, sustainable yield index (SYI), rain water use efficiency (RWUE) and soil properties under sorghum - black gram system in resource poor Semi-Arid Tropical (SAT) Alfisol at Hyderabad, India. The results revealed that when averaged over residue retention treatments, MT recorded 12.32 and 5.21% higher sorghum and black gram grain yield, 19.61 and 25.93% higher sustainability yield Index (SYI), and 12.27 and 5.15% rain water use efficiency (RWUE), respectively, over conventional tillage. Residue retention treatments (averaged over tillage treatments) S2 (cutting at 60 cm height for sorghum and 100% retention for black gram) and S1 (cutting at 35 cm height for sorghum and 50% retention for black gram) recorded 33.16 and 16.16, and 32.18 and 14.88% higher sorghum and black gram yield, respectively, over S0 (no residue) and also recorded 26.0 and 9.0, and 48.0 and 22.0% higher SYI over S0 in sorghum and black gram, respectively. Increase in RWUE under S2 and S1 over S0 was 33.19 and 16.23% in sorghum and was 31.4 and 14.53% in black gram. Higher residue retention maintained significantly higher soil organic carbon (SOC), significantly lower bulk density (BD) and significantly influenced potential of hydrogen (pH) and electrical conductivity (EC) at all the depths and also increased available nitrogen (N), phosphorus (P), potassium (K), manganese (Mn), iron (Fe), zinc (Zn) and copper (Cu) by 35.43, 24.55, 12.12, 57.6, 53.99, 51.46 and 13.76%, respectively. Thus, the results of the present study are highly useful in improving the crop yields, yield sustainability and soil properties. Therefore, the conservation agriculture practices can be a resource saving and higher crop production technology in the rainfed Alfisols.