Optimization of Nitrogen Dose under Different Irrigation Levels in Maize (Zea mays L.) during Post Monsoon Season at Rajendranagar, Hyderabad, India

A field experiment was conducted at Agro Climate Research Center, Rajendranagar, Hyderabad, India during post monsoon season of 2019-20 with an objective to optimize the nitrogen dose under varied degrees of water stress environment. The experiment was laid out in split plot design replicated thrice with three irrigation scheduling (60%DASM, 40%DASM and 20%DASM) as main plots and three nitrogen levels (90, 180 and 240 kg of nitrogen ha-1) as sub plots. The results indicated that, at 20% DASM, with increasing nitrogen dose from 90 to180 and further 240 kg ha-1, the plant height and biomass increased significantly. Whereas a significant response in terms of the LAI, number of grains row-1, grain and stover yields and nitrogen uptake by plant was observed up to 180 kg N ha-1.Under deficit soil moisture condition (60% DASM) the maximum plant height (141.5cm), LAI (2.93), biomass (222.3 g plant-1), number of grains row-1 (35.3) test weight (24.1 g), grain yield (4930 kg ha-1), stover yields (7996kg ha-1) and nitrogen uptake by plant was recorded with low nitrogen dose of 90 kg N ha-1 and all these parameters were decreased with increasing nitrogen dose. The concentration of nitrogen in leaf, stem and grain was more under deficit soil moisture condition (60% DASM) and was decreased with reliving plant water stress by scheduling irrigation at 40% DASM and 20% DASM. This investigation evidences the need of nitrogen optimization under varied degree of moisture availability. Under deficit irrigated situation, lower dose of nitrogen is sufficient for optimum yield. Whereas under sufficient water availability, the beneficial effect increased nitrogen levels can be exploited for higher grain yield in maize.