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通过在太湖地区持续施氮和土壤氮耗竭1年后再施氮的对比试验,研究了施氮量对水稻产量、干物质积累、植株吸氮量、氮肥利用效率和土壤氮素的影响。经过3季(稻-麦-稻)不施氮处理,第3季作物水稻的产量显著下降,仅6673.42kg/hm2;持续施氮和氮耗竭1年后施氮处理的产量均随着施氮量的增加而提高,但增产幅度逐渐减小,当施氮量为300kg/hm2时,水稻产量最高,分别为10514.95kg/hm2和10472.36kg/hm2,施氮量继续增加时水稻都出现倒伏而减产;各施氮处理植株的干物质积累、总吸氮量和土壤全氮含量都随施氮量的增加而提高,而氮肥利用效率都随施氮量的增加而降低;氮耗竭1年后施氮处理与持续施氮处理之间的各项指标变化不明显,说明这些指标与氮耗竭1年后的土壤背景氮关系不密切,而与当季施氮量有关。
The effects of nitrogen rate on rice yield, dry matter accumulation, nitrogen uptake by plants, nitrogen use efficiency and soil nitrogen were studied by comparing nitrogen application after one year of nitrogen and nitrogen depletion in Taihu Lake. After 3 years (rice-wheat-rice) no nitrogen treatment, the yield of rice in the third season decreased significantly, only 6673.42kg / hm2. After one year of continuous nitrogen application and nitrogen exhaustion, The yield of rice was gradually decreased. When the amount of nitrogen was 300kg / hm2, the yield of rice was the highest (10514.95kg / hm2 and 10472.36kg / hm2 respectively) The dry matter accumulation, the total nitrogen uptake and the soil total nitrogen content increased with the increase of nitrogen application rate, while the nitrogen use efficiency decreased with the increase of nitrogen application rate. After 1 year of nitrogen depletion There was no obvious change in the indexes between nitrogen application and continuous nitrogen application, indicating that these indicators are not closely related to the background nitrogen of soil one year after nitrogen depletion, but are related to the amount of nitrogen application in the current season.