Scientist, ICAR-National Rice Research Institute, Cuttack, Odisha
A field study was conducted at S.V. Agricultural College, Tirupati during rabi seasons of 2019-20 and 2020-21 to study the effect of drip irrigation regimes and nitrogen levels on phenology of aerobic rice. The field experiment was laid out in split plot design with three replications by taking irrigation regimes (Drip irrigation at 1.25 Epan, 1.50 Epan, 1.75 Epan and 2.0 Epan) as main plots, and nitrogen levels (90 kg N ha-1, 120 kg N ha-1, 150 kg N ha-1 and 180 kg N ha-1) as sub plots. Higher leaf area duration (LAD) was observed with drip irrigation regime of 2.0 Epan which was however comparable with drip irrigation at
1.75 Epan) at different intervals of crop growth except at 0-30 DAS interval, wherein irrigation regimes did not have significant influence on LAD. The lower LAD was observed with drip irrigation regime of 1.25 Epan at all the stages of crop growth. As regards to nitrogen levels higher LAD was observed with 180 kg N ha-1 which was however comparable with 150 kg N ha-1 at 30 DAS, and the lower value was observed with 90 kg N ha-1. In the pooled mean, drip irrigation regime of 2.0 Epan and 1.75 Epan took significantly less number of days to attain 50% flowering over 1.5 Epan and 1.25 Epan. Aerobic rice supplied with 180 kg N ha-1 took less number of days to attain 50% flowering followed by lower doses and 90 kg N ha-1 took longer duration to attain 50% flowering. Number of days to maturity was non-significant due to irrigation regimes and nitrogen levels during both the years of study and in the pooled mean.
KEYWORDS: Aerobic rice, days to 50% flowering, drip irrigation regimes, leaf area duration, nitrogen levels