Productivity and nitrogen use efficiency of rice under conventional and organic nutrition

The current study demonstrates the influence of conventional and organic nutrient management practices on nitrogen use efficiency, growth, yield, and physiological and biochemical parameters in four rice varieties, namely, Jaiva, Ezhome 2, Jyothi and Uma. Growth parameters, grain yield per hill, and physiological and biochemical parameters were higher under conventional management for all rice varieties. Although the nitrogen use efficiency of each variety varied significantly with nutrient management practices, the variation was least in Jaiva (23.8%), which is the organic rice variety released by Kerala Agricultural University. The rice varieties Jaiva and Ezhome 2 showed consistency in the grain weight per panicle under both conventional (Jaiva- 4.57 g, Ezhome 2- 5.86 g) and organic (Jaiva, 4.24 g, Ezhome 2, 4.54 g) management. The soil nitrogen content at the tillering stage (0.66**) showed a significantly higher positive correlation with nitrogen use efficiency under organic management. The results of the study provide a better understanding of factors that can lead to a sustained yield in organic rice production in terms of nitrogen use efficiency.