Soil and Plant Nutrient Dynamics in Castor-based Cropping Systems as Influenced by Conservation Agricultural Practices

Abstract

A field experiment was conducted during kharif 2021, at Narkhoda farm, ICAR-Indian Institute of Oilseeds Research, to study the effect of conservation agricultural practices on soil and plant nutrient dynamics. The experiment was laid out in split-plot design with 3 replications on red sandy loam soil (Alfisols) under rainfed conditions. The treatments comprised of three tillage treatments in main plots viz., conventional tillage, reduced tillage, zero tillage and four cropping systems with residue incorporation in subplots viz., sole castor, castor + redgram (1:1), castor + greengram (1:3) and castor + groundnut (1:3). The results indicated that at harvest, highest soil organic carbon (SOC) content was found in reduced tillage (0.64%) followed by zero tillage (0.63%) and the lowest in conventional tillage (0.56%). Among inter cropping systems, SOC was recorded highest (0.67%) in castor + redgram (1:1) and lowest (0.55%) in sole castor treatment. The status of post-harvest soil available N, P, K (kg/ha) was recorded highest in reduced tillage (208.6, 54.03, 515.9 kg N, P, K /ha respectively) and lowest in conventional tillage (196.7, 38.57, 486.8 kg N, P, K /ha) while, zero tillage (203.6, 47.15, 506.7 kg N, P, K /ha) was at par with the reduced tillage. Among the cropping systems, castor + redgram (208.1, 60.12, 517.9 kg N, P, K /ha) recorded highest available N, P, K while lowest in sole castor (201.6, 38.60, 494.0 kg N, P, K /ha) treatment. Total N, P, K uptake (kg/ha) by castor crop at harvest was highest in conventional tillage (56.13, 19.99, 31.97 kg N, P, K /ha respectively) followed by reduced (49.24, 16.81, 26.28 kg N, P, K /ha) and the lowest (38.36, 13.15, 21.99 kg N, P, K /ha) was recorded in zero tillage. Among intercropping cropping systems N, P, K uptake by castor crop was recorded highest in sole castor (60.22, 18.66, 32.35 kg N, P, K /ha) treatment while lowest was recorded in castor + redgram (1:1) (26.65, 10.28, 15.93 kg N, P, K /ha). In general, the interaction effect between tillage and intercropping system were found non-significant.