Combined Effect of Slow-release Fertilizer and Irrigation Method on Growth, Yield and Grain Quality of Rice

【Objective】 Slow-release fertilizer is efficient and environmentally friendly but its effectiveness is closely related to soil water. This paper studies the combined impact of slow-release fertilization and irrigation method on growth, yield and quality of rice. 【Method】 The pot experiment was conducted from May to September in 2021 at Hubei Irrigation Central Experimental Station. It consisted of flood irrigation (W1) and alternate wetting and drying irrigation (W2). Each irrigation treatment had 6 fertilizations: conventional fertilization (F100), fertilizations using 120% (SF120), 110% (SF110), 100% (SF100), 90% (SF90) and 80% (SF80) of the fertilizer used in F100 but replacing them by controlled-release fertilizer. In each treatment, we measured the plant height, numbers of tillers, chlorophyll SPAD, yield and its components, as well as amylose and gluten protein contents in each growth stage. The entropy weight TOPSIS method was used for comprehensive evaluation of the treatments. 【Result】 Compared with F100, on average over the two irrigation treatments, SF100 increased plant height, tiller numbers, grain yield and glutenin content by 24.65%, 34.90%, 11.90% and 32.72%, respectively, while reduced the chlorophyll degradation and amylose content by 24.98% and 7.37%, respectively. Compared with W2, W1 increased the average plant height, chlorophyll degradation, and yield by 19.01%, 20.73%, and 12.82%, respectively, and reduced the number of tillers and the contents of amylose and glutenin by 31.05%, 0.30%, and 0.90%, respectively. Under W1, the yield of SF90 was 12.41% higher than that of SF120; the amylose content in SF90 was 6.68% lower than that in SF120; the glutenin content in SF90 was 5.33% lower than that in SF110. The entropy weight TOPSIS method showed that the relative yield of W1+SF90 was the closest to the potential yield, with the comprehensive score reaching 0.985. 【Conclusion】 Combining flood irrigation with a 10% reduction of conventional fertilization by using slow-release fertilizer (648 kg/hm2 fertilizer) is a promising irrigation-fertilization for rice production in the middle and low reaches of the Yangtze River basin.