Title: Impact of Different Nitrogen Amount and Seeding Rates on Growth and Yield of NERICA 4 Rice Varieties in Upland Conditions
Abstract: With the recent breakthrough in the development of the New Rice for Africa (NERICA) for the upland production system and the high demand for rice, farmers’ interest in growing upland rice has increased. A field experiment was conducted at Tsukuba International center, Japan from May to October 2019 to evaluate the response of rice to seed rate and nitrogen fertilizer application and also determine economically optimum seed rate and nitrogen level for NERICA-4 upland variety. The experiment contained factorial combination of four levels of nitrogen (0, 30, 60, 90 kg ha -1 and two seed rates (60& 80 Kg ha -1 ). The experiment was laid out in randomized complete block design plot arrangement with three replications. The results from this study indicated that seed rate showed no significant effect on total dry matter weight, plant length, SPAD value, Leaf area index, panicle number, spikelet number, ripening ratio and grain yield while the total number of tillers was significant. However, nitrogen fertilizer rates significantly (p < 0.05) affected in plant length, tiller number, SPAD value, dry matter and Leaf area index. Except 1000grain, all the yield and yield component parameters have also shown a significant increase up to the rate of 90 kg N ha−1. The highest grain yield (3340 kg∙ha−1) was recorded using 90 kg N ha −1 followed by 60 kg N ha −1 (3200 kg ha −1) and the lowest yield (2100 kg ha −1 ) was recorded from control . Marginal rate of return analysis is also showed that the treatment with N fertilizer rate of 90 kg N ha −1 and seed rate 60 kg ha −1 gave the highest Marginal rate of return 1217 % followed by the treatment with N fertilizer rate of 60 kg N ha−1 and seed rate 60 kg ha−1.The general trend of the data indicated that the fertilizer rate has a greatest impact on grain yield compared to the seed rate of rice crop. Based on this study using 60 kg/ha seed rate and application of 90 kg N ha −1 gives high grain yield for rice crop production at experimental site. Keywords : Economic profit, Seed rate, N fertilizer rate, Optimum grain yield, Marginal rate of return DOI: 10.7176/JNSR/12-4-05 Publication date: February 28 th 2021