Basmati rice (Oryza sativa) performance with varying irrigation and nitrogen control

Abstract

At the ICAR-Indian Agricultural Research Institute research farm in New Delhi, a field experiment was carried
out during the rainy seasons (kharif) of 2021 and 2022 to investigate the impact of irrigation schedules and the
combined use of prilled urea and nano-urea as a source of N on the productivity and profitability of basmati rice
(Oryza sativa L.). Three irrigation regimes—irrigation at 1, 3, and 6 days after disappearance of surface water
(DADSW) assigned to main-plots—and four N-management variations—100% RDN (recommended dose of N,
120 kg/ha); 75% RDN + 4% nano-urea (NU) 2 sprays (75% RDN + 2 NU); 50% RDN + 2 NU; and no-N
(control) in sub-plots—were used in the experiment. In comparison to 3 and 6 DADSW, irrigating basmati rice
1 DADSW showed the greatest panicle weight (2.67–3.09 g) and number of grains/panicle (115.9, 109.8) over
the years. Grain production was significantly reduced by the most delayed irrigation at 6 DADSW; the decline
was 13–19% over irrigation at 3 DADSW and significantly by 23–28% over irrigation at 1 DADSW. The yield
attributes and grain yield of rice crops fertilized with 100% RDN and 75% RDN + 2 NU were statistically
similar, but both were significantly better than 50% RDN + 2 NU and no-N. Net returns, benefit cost (B:C) ratio,
and monetary efficiency were significantly higher when the crop was irrigated 1 DADSW compared to 3 and 6
DADSW. For all examined economic factors, the N-management alternatives followed the trend of RDN>75%
RDN + 2 NU ˃50% RDN > no-N.