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南方红壤丘陵地区降水集中且多暴雨,土层薄,易被冲刷侵蚀,坡地农林开发中以径流为载体传输的氮素面源污染对水环境造成威胁。本文利用大型土壤渗漏装置,在施肥前、施肥后、施肥后一年3个不同时期3场自然降雨事件下,对植草覆盖、干草敷盖和裸露3种处理下红壤坡面氮素随径流垂向分层输出特征进行分析。结果表明:地表径流总氮(TN)输出量各处理排序为裸露>干草敷盖>植草覆盖,壤中流和地下径流总氮的输出量干草敷盖>裸露>植草覆盖。在暴雨条件下红壤坡面径流中总氮分层输出以地下径流为主(占55.28%~95.30%),氮素流失不仅体现在地表(占0.12%~42.16%),更多地还体现在地下的壤中流和地下径流。植生覆盖和枯落物覆盖等水土保持措施有利于可溶性无机氮的下渗。
In the hilly red soil region of South China, precipitation is heavy and rainstorm. The soil layer is thin and easily eroded. The non-point source pollution of nitrogen transported by runoff as a carrier in sloping agroforestry is threatening the water environment. In this paper, with large soil seepage device, under the natural rainfall events of 3 different periods of one year after fertilization, before fertilization and after fertilization, the effects of runoff, Vertical stratified output characteristics for analysis. The results showed that the total nitrogen (TN) output of surface runoff was ranked as follows: bare> hay cover> grass cover, soil middle runoff and total nitrogen output hay cover> naked> grass cover. Under heavy rain conditions, the runoff of total nitrogen in the runoff of red soils is dominated by underground runoff (55.28% -95.30%). Nitrogen loss is not only reflected in the surface (0.12% -42.16%), but also reflected in Underground soil and underground runoff. Soil and water conservation measures such as vegetation cover and litter coverage are conducive to infiltration of soluble inorganic nitrogen.