Agro-meteorological indices and phenology of rice (Oryza sativa L.) under different dates of planting and nitrogen levels

Abstract

A field experiment was conducted during Kharif season of 2016 at Research Farm of Odisha University of Agriculture and Technology, Bhubaneswar, India to study the phenology and various agro-meteorological indices viz., accumulated growing degree days (GDD), heliothermal units (HTU), photo thermal units (PTU), and heat use efficiency (HUE) of rice variety ‘Hasanta’ grown under different dates of transplanting and nitrogen levels. The rice variety ‘Hasanta’ was transplanted on four dates viz., 10th July, 20th July, 30th July and 10th August with three levels of nitrogen 75%, 100% and 125% of recommended dose of fertilizer, respectively. The crop transplanted on 10th July took maximum calendar days to attain different phenological stages till physiological maturity (143.74 days) which reduced significantly with subsequent delay in transplanting date with highest growing degree days (2677.2) for maturity, heliothermal units (13531 degree day hours) and photo thermal units (417923 degree day hours), heat use efficiency was found to be highest 0.88(g/m2/ oC day), when transplanted on 10th July followed by 20th July and 30th July. Heat units required to attain different phenological stages decreased in all the varieties with delay in transplanting date. Planting on 10thJuly with application (125% nitrogen) produced maximum grain yield of 4443 kg/ha which was at par with planting on 10th, 20th, and 30thJuly with applying either 125% nitrogen or 100% nitrogen.