泥沙研究

研究了降雨产流过程中径流和泥沙中N素的含量变化特征,次降雨产流过程中径流中的全N和水解N的含量与产流过程“相似”,也会出现一个峰值,产流初期全N和水解N的含量低,随着产流量的增加,它们的含量会出现一个峰值,尔后其含量降低;径流中的全N和水解N的含量随着坡耕地坡度的增加其含量均呈下降趋势。侵蚀泥沙中的全N和水解N的含量分别高于土壤表层中的全N和水解N的含量,产生所谓的“富集”现象;随着坡耕地的坡度的增加,侵蚀泥沙中的全N含量亦呈下降趋势。依据侵蚀泥沙中的N素含量估算得出黄土高原南部100.82万hm2的坡耕地年均损失N素2.31万t。

The concentrations of the total N and dissolved N in the runoff show the same trends during the runoff yielding process.At the begin, their values are low,and they become the biggest accompanied with the peak value of the runoff yielding,then they become lower with the fade of runoff.The concentration of the total N and dissolved N become declined with the slope land gradient increase.The concentrations of total N and dissolved N in the sediment flow was higher than those in the soil.And their contents become lower with the slope land gradient increase.According the statistics of the slope lands in the South Loess Plateau,the annual amount of nutrient N losses is 23.1 million kilograms in the 1.0082 million hectares.