Effect of N disposable application rates on the growth and yield of rice with plastic film covering | 一次性施N对地膜水稻生长发育及产量的影响

Chinese. 探索一次性不同施N量对地膜水稻生长发育和产量的影响。以优质水稻“两优6326”为材料，在水稻覆膜前，分别一次性施用0(CK)，75，150，225，300 kg/hm2 N肥，插秧后每周调查1次分蘖数，在始穗期前1周、齐穗期前1周和收获期前1周测定水稻光合参数、叶绿素含量，并于收获期统计水稻产量，通过经济效益曲线拟合，分析最佳施N量。施N量的增大，可以增加地膜水稻叶片叶绿素含量，增强光合作用，促进地膜水稻分蘖，水稻产量也相应增加。除了净光合速率外,施用N肥对气孔导度、胞间CO2浓度、蒸腾速率、叶片温度等光合参数总体上均无显著影响。当施N量为300 kg/hm2时，叶片叶绿素含量在始穗期前1周最高，为48.38 mg/g，水稻分蘖数高达44.42个/穴；当施N量为225 kg/hm2时，水稻有效穗数和产量均最高，分别为225.60万株/hm2和10 172.25 kg/hm2，与施Ｎ量300 kg/hm2差异不显著。经济效益曲线拟合结果显示，地膜覆盖栽培水稻时，一次性最佳施N量为285.37 kg/hm2，此时理论产量达10 062.57 kg/hm2。

English. Exploration was done on the effect on rice growth and yield of the different N disposable application rates under the condition of film mulching cultivation. High quality rice “Liang-you 6326” was used as plant material. Five different designs: 0(CK), 75, 150, 225, 300 kg/hm2 of the Nitrogen Fertilizer were applied before film mulching. The tiller number was counted once every week after transplanting. Then the effect photo out, chlorophyll content and yield were measured one week before initial heading stage, full heading time and harvest time of the rice. The best N application rate was analyzed by economic benefit of curve fitting. In the experiment, with the increase of the N application rate, the physiological indexes of photo out, chlorophyll content and the tillers all increased. But the yield showed a decreasing tendency when the yield increased to a certain degree. N application had no significant effect on photosynthetic parameters, such as: cond out, ci out, trmmol out and leaf except the photo out. When the Maximum N application rate was 300 kg/hm2, the chlorophyll content was 48.38 mg/g, the highest at initial heading stage, and the tillers per hill reached 44.42 ind. But there was no obvious difference with the nitrogen application 225 kg/hm2, the effective panicle number reached 225.60×104 plants/hm2, and yield reached 10 062.57 kg/hm2. Through the nonlinear curve fit, the results showed that: 285.37 kg/hm2 was the best N disposable application rate under the condition of film mulching, and 10 062.57 kg/hm2 was the highest theoretical yield.