Abstract:
In order to explore the optimal amount of nitrogen fertilizer applied to rice in eastern Fujian, and perfect & optimize the fertilization scheme, the experiment was carried out in Xiapu County, and based on the optimized fertilization formula of local rice (N of 135 kg·hm
-2, P
2O
5 of 54 kg·hm
-2, and K
2O 94.5 kg·hm
-2), the effects of different nitrogen application rates (nitrogen-free area, 70% optimized nitrogen application area, optimized nitrogen application area and 130% optimized nitrogen application area) on the rice yield, nitrogen use efficiency, comprehensive economic benefits and soil alkaline hydrolysis nitrogen content were studied. The results showed that: When the nitrogen application rate was 135.0 kg·hm
-2, the yield of rice was the highest. When the nitrogen application rate was 175.5 kg·hm
-2, the yield of rice straw was the highest. The excessive nitrogen fertilizer reduced the yield of paddy rice, but increased the yield of rice straw. The nitrogen fertilizer use efficiency of rice decreased with the increase of nitrogen fertilizer application rate. The utilization rate of nitrogen fertilizer in 70% optimized nitrogen application area, optimized nitrogen application area and 130% optimized nitrogen application area was 42.22%, 40.17% and 36.12%, respectively. By using the equation fitting, it was estimated that when the nitrogen fertilizer application rate exceeded 164.21 kg·hm
-2, the economic benefit was the highest, which could be used as the highest control variable of the local nitrogen fertilizer application. The soil alkaline hydrolysis nitrogen in the nitrogen-free zone decreased significantly compared with other treatments, which would affect the supply level of soil nitrogen.