Sulphur coated urea improves morphological and yield characteristics of transplanted rice (Oryza sativa L.) through enhanced nitrogen uptake

Imbalanced and non-judicious use of nitrogen in agriculture is one of the major factors responsible for ecological disturbance and threat to biodiversity. Among cultivated crops, nitrogen losses in rice are the highest that resulted in low nitrogen use efficiency. Urea coating with sulphur can deaccelerate nitrogen release and contribute to higher availability for plants. An experiment was conducted during two consecutive years 2016 and 2017 for the assessment of sulphur coating on urea in transplanted rice under varied nitrogen levels. There were two levels of urea source, U1 = granular urea (UG) and U2 = sulphur coated urea (USC) and three levels of nitrogen rate were kept as, N1 = 100% of the recommended nitrogen (160 kg ha−1), N2 = 75% of the recommended nitrogen (120 kg ha−1) and N3 = 50% of the recommended nitrogen (80 kg ha−1). Results indicated that in both years highest kernel yield was recorded in USC as compared to UG. Almost all morphological traits were influenced by nitrogen levels and urea sources. Chlorophyll a and b were also significantly higher in USC at 90 and 120 DAT (days after transplanting). Nitrogen contents in leaf and panicle were also increased when nitrogen was applied in form of USC. Leaf nitrogen contents were almost same at 90 and 120 DAT while panicle nitrogen contents increased significantly at 120 DAT under USC. It is concluded that urea coating with sulphur is more efficient than application of granular urea. To obtain higher yield in puddled rice, it is recommended that nitrogen must be applied at the rate of 160 kg ha−1 through coating of sulphur.