Impacts of Nitrogen Fertilizer and Planting Density on Growth Characteristics and Yield of Super Rice

【Objective】This study was carried out to clarify the effects of nitrogen fertilizer and planting density on rice growth characteristics and yield, and to understand the suitable density treatment and nitrogen fertilizer application rate for different varieties, in order to provide theoretical basis and technical support for high quality and high yield of super rice.【Method】Super rice varieties Shenyou 9516 and Rongyou 225 were used as experimental materials. Three planting densities 24×104 holes/hm2 (D1), 27×104 holes/hm2 (D2) and 30×104 holes/hm2 (D3) and four nitrogen application rates 0 kg/ hm2 (N0), 120 kg/hm2 (N1), 150 kg/hm2 (N2) and 180 kg/hm2 (N3) were set up. The plant height, leaf area index and dry matter accumulation were measured in the key growth period of rice, and the yield and yield components were measured in the mature period.【Result】Compared with N0 treatment, the plant height, leaf area index (LAI) and dry matter accumulation increased with the increment of nitrogen application rate, which showed the trend of N3 > N2 > N1 > N0. The two varieties showed the same performance in the key growth period of early and late seasons (tillering stage, young panicle differentiation stage, full heading stage). Compared with D1 treatment, plant height, leaf area index and dry matter accumulation increased with the increment of density, presented as D3 > D2 > D1. Comparing the yield, it was found that the yield of Shenyou 9516 treated with N1D3 and Rongyou 225 treated with N3D3 in early rice, Shenyou 9516 treated with N3D1 and Rongyou 225 treated with N2D3 in late rice was the highest. Analysis of variance showed that plant height, leaf area index, dry matter accumulation, yield and yield components were significantly or extremely significantly positively correlated with nitrogen application rate and planting density, and nitrogen fertilizer and density had interaction effects, among which interaction of and nitrogen density had positive effects on plant height, LAI, dry matter accumulation, effective panicles and yield.【Conclusion】Combined with the growth characteristics and yield characteristics of rice, Shenyou 9516 should adapt the combination of pure nitrogen application rate of 180 kg/hm2 (N3) and density of 27×104 holes/hm2 (D2); Rongyou 225 should use the combination of pure nitrogen application rate of 180 kg/hm2 (N3) and density of 30×104 holes/hm2 (D3).