Synergistic Influence of Sulphur and Boron Fertilization on Enhancing the Productivity of Rapeseed (Brassica napus L.) and Nutrient Status in Subtropical Acidic Soil of Assam, India

Abstract

ABSTRACT Rapeseed has an immense requirement for S and B, largely for the biosynthesis of glucosinolates and S amino acids. The present investigation was conducted for three consecutive rabi seasons of the year 2014–17 in rapeseed (cv.TS-38) to assess the impact of S and B fertilization on crop yield, soil chemical properties and nutrient status. Results of three years of investigations indicated that among the various soil chemical properties, the combined appliance of S and B level of S30B1.5 (30 kg S ha−1 + 1.5 kg B ha−1) significantly augmented the SOC, while soil pH, Fe2O3 and Al2O3 content in soil were found to be non-affected significantly. Interaction effect between S and B significantly affected available primary nutrients as fertilization with S30B1.5 registered maximum available N (298.7 kg ha−1), P (31.0 kg ha−1) and K (126.2 kg ha−1), respectively. Application of the same levels of S30B1.5 enhanced the status of exchangeable Ca and Mg, available S and B up to 0.90 cmol(p+) kg−1, 0.50 cmol(p+) kg−1, 13.67 mg kg−1 and 0.65 mg kg−1, respectively. The NUE in soil were found to improve on scaling both the levels of S and B. Yield attributing characters were not significantly affected by graded levels of S and B, however, there was a significant improvement in seed yield, stover yield and biological yield of rapeseed. Yield gap analysis exhibited that the combined application of S30B1.0 resulted in the lowest yield gap of 275 kg ha−1 while the control plot recorded the highest yield gap of 647 kg ha−1. Correlation study indicated the existence of a highly significant correlation among most of the soil parameters under investigation. Path analysis revealed that available P was the most dominant soil nutrient implicated in improving the BYR. The inclusive results indicated that higher levels of both S and B could improve the soil fertility status and yield of rapeseed.