Effects of Integrated Organic and Inorganic Fertilizers on Yield and Growth Parameters of Rice Varieties

We investigated the effects of integrated organic and inorganic fertilizers on the growth and yield of indica rice variety Manawthukha and japonica rice variety Genkitsukushi. In a split-plot design, the two rice varieties were assigned as main plot factors, and the integrated treatments were the subplot factors, including no-N fertilizer (N₀), 50% chemical fertilizer (CF) (CF₅₀), 100% CF (CF₁₀₀), 50% CF + 50% poultry manure (PM) (CF₅₀PM₅₀), 50% CF + 50% cow manure (CM) (CF₅₀CM₅₀), and 50% CF + 50% compost (CP) (CF₅₀CP₅₀). CF₁₀₀ was equivalent to N at 85 kg/hm². Manure was applied based on the estimated mineralizable nitrogen (EMN) level, which is dependent on total N (%) of each manure type. Manawthukha rice plants were taller with higher tiller number and dry matter content. However, higher soil-plant analysis development (SPAD) values were measured in Genkitsukushi throughout the crop growth period, resulting in higher seed-setting rate (%) and greater yield. At the same N level, CF₅₀PM₅₀ application in both rice varieties resulted in higher SPAD values, plant height and tiller number than CF₁₀₀. CF₅₀PM₅₀ containing total N more than 4% supplied synchronized N for the demands of the rice plants, resulting in maximum dry matter, yield and yield components. CF₅₀CM₅₀ and CF₅₀CP₅₀ treatments containing total N less than 4% resulted in lower yields which were similar to CF₁₀₀. These results indicated that integrating organic and inorganic fertilizers enhanced growth parameters and yields of Manawthukha and Genkitsukushi, while reducing the dose of chemical fertilizer.