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采用人工模拟降雨方法研究裸地(BL)、花生(PL)、50%裸地+50%花生(BP)、50%玉米+50%花生(CP)和秸秆覆盖(SC)5种农作方式下,丹江鹦鹉沟小流域坡面小区径流氮素流失规律。结果表明:地表径流总量表现为裸地BL>SC>CP>BP>PL;随降雨时间延续,地表径流均呈不同程度增加趋势,其中BL小区增长速度最快,BP措施下出流时间最长(降雨后第6min),花生立地条件下每5min地表径流变化稳定在0.30~3.46L之间。径流中氮素流失浓度表现为BP>CP>PL>BL>SC,随时间呈波动增加趋势,沿坡面由上至下表现为先减小后增加。受农作方式的影响,氮素流失在时间、空间上变化规律不同;总氮、硝态氮流失浓度最大增幅分别可达45.54%和55.79%,流失量分别在15.90~110.81mg/m2和15.58~90.33mg/m2之间;径流中氮素浓度的变异性略大于对应的地表径流。农作方式与硝态氮呈正相关,与总氮相关性不显著。在鹦鹉沟小流域农田养分流失不容忽视,需进一步采取有效的水土保持措施。秸秆覆盖措施既能有效保持土壤养分,又可保证入河径流量,是值得推荐的水保措施。
Artificial simulated rainfall methods were used to study five farming methods: bare land (BL), peanut (PL), 50% bare land with 50% peanut (BP), 50% maize + 50% peanut (CP) and straw mulching (SC) Under the law of Danjiang Parrot Valley small watershed slope area runoff nitrogen loss. The results showed that the total amount of surface runoff was BL> SC> CP> BP> PL. With the extension of rainfall duration, surface runoff increased in varying degrees. Among them, BL grew fastest and BP Long (6 min after rainfall), the change of surface runoff every 5 min under the peanut site was stable at 0.30 ~ 3.46L. The concentration of nitrogen loss in runoff showed BP> CP> PL> BL> SC, which showed a trend of increasing with time, decreasing and then increasing along the slope from top to bottom. Affected by the farming methods, the nitrogen loss varied in time and space. The maximum increase of total nitrogen and nitrate nitrogen loss was 45.54% and 55.79%, respectively, and the losses were 15.90 ~ 110.81mg / m2 and 15.58 ~ 90.33mg / m2; the variability of runoff nitrogen concentration is slightly larger than the corresponding surface runoff. The mode of farming was positively correlated with nitrate nitrogen but not significantly with total nitrogen. The nutrient loss of farmland in the Pomatigou small watershed should not be neglected, and effective measures for soil and water conservation should be taken. Straw cover measures can not only effectively maintain soil nutrients, but also to ensure that runoff into the river, it is recommended water conservation measures.