Impact of sulfur and boron fertilization on yield, quality of crop and nutrient use efficiencies in rapeseed in subtropical acidic soil of Assam, India

Abstract

Field experiments were conducted with rapeseed (cv.TS-38) for three consecutive rabi seasons of the year 2014–2017 at the Instructional-cum-Research farm of Assam Agriculture University, Jorhat. Results revealed that different levels of sulfur and boron and their combinations had significant influence on seed and stover yields of rapeseed. The highest seed and stover yields were registered in interaction effect of B and S at 20 kg S/ha + 1.5 kg B/ha which was closely followed by interaction effect of B and S at 30 kg S/ha + 1.5 kg B/ha. The highest total uptake of N and B was noted under 30 kg S/ha + @ 1.5 kg B/ha. The highest total S uptake was noted under application of 20 kg S/ha + @ 1.5 kg B/ha. Partial factor productivity of N, P and K increased with subsequent increase in levels of S and B up to 20 kg S/ha and 1.5 kg B/ha, respectively. The highest values of agronomic use efficiency and apparent recovery of S and B were registered under 10 kg S/ha and 0.5 kg B/ha, respectively. The highest values of physiological use efficiency of S and B were registered under 20 kg S/ha and 0.5 kg B/ha, respectively. Interaction effect of S and B at 30 kg S/ha + 1.0 kg B/ha (S30B1.0) improved the oil content to the tune of 35.6%, registering an improvement of 13.4% over the control. The same interaction resulted in enhancement of protein content up to 22.9% over the 19.8% (control) wherein 15.6% increase over the control was noticed. Multiple stepwise regressions exercised on the different nutrient uptakes showed that nitrogen content in seed contributed the most in augmenting the biological yield of rapeseed followed by phosphorus and sulfur.