关键词: 氮肥, 水稻, 生长发育, 动态变化, 产量, 推荐施肥量

Abstract:

The Liaohe Delta, single-cropping rice region belongs to the main rice-producing area in Liaohe Plain. The local farmers rely too much on additional chemical fertilizers to improve rice yield, resulting in high input of nitrogen fertilizer and low use efficiency. Based on the biological response of rice to nitrogen in the growth cycle, the agronomic characteristics of rice including plant height, SPAD value, tillering number, and yield parameters of rice under different nitrogen fertilizer rates were investigated. The results showed that plant height, SPAD value of flag leaves and tiller numbers were positively correlated with the amount of nitrogen fertilizer. Higher Nitrogen treatment results in prolonged tillering period, which could lead to the late maturity of rice shoot. In terms of yield factors, the yields of medium and high nitrogen treatments (N210, N260 and N315) was the highest, compared to low nitrogen treatment (N160) and (N420) treatment. decreased significantly compared to them due to lack of nitrogen and nitrogen excess. The yield components of N420 treatment, including grain number per ear, rate of grain filling and 1000-grain weight, were significantly lower than those of the three treatments with higher yield. The yield and nitrogen application rate accorded with the yield-response curve of linear plus platform. According to the equation, the optimum nitrogen application rate in this area was 225kg/ha. Although nitrogen use efficiency of N210 treatment was the highest (42%), considering the nitrogen balance of soil-plant system, it was suggested that the nitrogen application rate should be between 221-235kg/ha in Liaohe River Delta. In the view of the above results, it is recommended that the reasonable threshold of nitrogen fertilizer application rate in Liaohe River Delta should be 225-235kg/ha.

Key words: Nitrogen, Rice, Growth and development, Dynamic change, Yield, Optimal nitrogen application rate