Physiological Characterization of Rice Genotypes at Different Nitrogen Levels

Nitrogen is the most important macro nutrient to rice production and its uptake is affected by fertilizer application, soil conditions and environmental factors. Selection of the most appropriate rate of N fertilization is a major concern affecting both economic viability of rice production and their impact on the environment. The optimum rate of nitrogen fertilization is the rate that results in maximum economic yield. In order to optimize productivity and reduce nitrogen losses a field experiment was conducted with nine rice genotypes, namely, Ajaya, BPT-5204, NDR-3 59, Pusa Basmati 1, Taroari Basmati, Vasumati, KRH-2, PA 6444 & PHB71. Nitrogen fertilizer was applied in the form of three splits and at three different levels N_o, N₁₀₀ & N₂₀₀. The response of different varieties at different levels was recorded and it was observed that split application of fertilizer nitrogen was the most effective at N₂₀₀ level. The growth parameters like TDM, CGR, yield, HI& LAI and nitrate reductase activity were found to increase with increasing N level. The NUE value also increased and was highest for PA 6444, which showed that it was the most nitrogen use responsive genotype.