Influence of Time of Planting, Spacing, Seedling Number and Nitrogen Management Practices on Productivity, Profitability and Energetics of Rice (Oryza sativa) in Island Ecosystem

Abstract

Field experiments were conducted during wet season of 2007 and 2008 at Central Agricultural Research Institute, Port Blair, Andaman and Nicobar Islands in order to evaluate the practices of System of Rice Intensification (SRI) in Island ecosystem. Time of planting, spacing and nitrogen management practices significantly influenced the growth and yield attributes while number of seedlings/ hill did not exert any influence on these parameters. Planting in second fortnight of June with 20 x 20 cm spacing recorded higher number of tillers (18.3), DMP (17.6), panicles/m 2 (9.2) and filled grains/panicle (9.1). As a result of better growth and yield components, higher grain yield (4,678 kg/ha), net returns (Rs. 31,768/ha), net return per rupee invested (1.47) and energy ratio (14.5) were recorded in the early planting. Application of 100 % Recommended Dose of Nitrogen (RDN) through urea recorded more number of tillers with higher DMP, number of panicles, more number of filled grains and highest grain yield of 4,465 kg/ha but it was comparable with 50 % RDN through Gliricidia + 50 % RDN through urea and 75 % RDN through Gliricidia + 25 % RDN through urea. Though the net return was slightly higher (Rs. 29,002/ha) with application of 100 % RDN through urea, but net return per rupee invested was higher (1.40) with application of 50 % RDN through Gliricidia + 50 % RDN through urea. Thus, planting in second fortnight of June with 20 x 20 cm spacing using single seedling combined with application of 50 % N through Gliricidia and 50 % N through urea can be recommended for achieving higher productivity, profitability and energetic of rice in island ecosystem.