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为探究沟施氮肥后,氮素随地表径流的流失规律,在野外降雨模拟试验条件下,研究了农田裸地氮素随地表径流流失规律。结果表明,在一定雨强范围内,土壤前期含水率对产流特征影响显著;在该裸地试验场地条件下,硝态氮质量浓度输出变化过程和总氮表现出良好的相关性,是氮素输出的主要形态;且硝态氮质量浓度随时间的变化曲线下降部分的下降速率具有一定规律性,用幂函数曲线拟合的结果最好,R2均在0.90以上;3次事件的地表径流累积量与累积氮素流失量成良好的正相关关系,可对观测值用幂函数和线性函数进行分段拟合。合理施肥,并尽量避免在强降雨来临前施肥,可以减缓施肥不当所造成的农业面源污染。
In order to explore the law of nitrogen loss with surface runoff after nitrogen fertilizer application in the furrow, the rule of nitrogen loss with surface runoff in farmland was studied under field rainfall simulation test. The results show that, in a certain range of rainfall intensity, the effect of early soil moisture content on runoff characteristics is significant. Under the bare soil conditions, the change of nitrate nitrogen concentration and output shows a good correlation with TN, And the main form of the output of nitrate nitrogen. The declining rate of the decline of nitrate nitrogen concentration with time had a certain regularity. The fitting curve of power function curve was the best, R2 was above 0.90. The surface runoff of three events Cumulative amount and cumulative nitrogen loss into a good positive correlation, the observations can be fitted with a power function and linear function of the segment. Rational fertilization and try to avoid fertilization before the onset of heavy rainfall can reduce agricultural non-point pollution caused by improper fertilization.