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利用野外模拟人工降雨试验,对人为加速侵蚀下耕地、草地和林地的水土与养分流失进行耦合研究。结果表明:人为加速侵蚀后养分随径流和泥沙的迁移,导致土壤肥力下降,其中泥沙结合态是养分流失的主要途径。耕地翻耕后加速土壤侵蚀,除产流量减少22.4%外,侵蚀速率和产沙量分别增加了27.1%和27.3%;总有机碳、总氮和总磷流失量分别增加104.5%,42.5%和59.5%。草地和林地的蓄水保土效果显著,开垦后侵蚀速率分别增加了188.9%和10 225.1%,产沙量分别增加了190.6%和9 370.0%,产流量分别增加了44.9%和85.3%;流失总有机碳、氮和磷量分别增加104.1%,69.9%和18.2%。林地去除枯枝落叶层后总有机碳、总氮、总磷流失量分别是自然状态下的6.1,4.7,15.1倍,且养分流失以可溶态养分为主;而开垦后流失总量分别是自然状态下的18.1,8.6,27.2倍,且养分流失以泥沙结合态为主。
Field simulated artificial rainfall experiments were conducted to study the coupling of soil and water loss on cultivated land, grassland and forest under artificial accelerated erosion. The results showed that the man-made accelerated nutrient migration with runoff and sediment led to the decline of soil fertility, and the sediment-bound state was the main way of nutrient loss. In addition to the 22.4% reduction in runoff, the erosion rate and sediment yield increased by 27.1% and 27.3%, respectively; the total organic carbon, total nitrogen and total phosphorus loss increased 104.5%, 42.5% and 59.5%. Grassland and woodland had significant water storage and soil conservation effects. After reclamation, the erosion rates increased by 188.9% and 10 225.1%, respectively. The sediment yield increased by 190.6% and 9 370.0% respectively, and the runoff increased by 44.9% and 85.3% respectively. Total organic carbon, nitrogen and phosphorus increased 104.1%, 69.9% and 18.2% respectively. After removing litter layer, total organic carbon, total nitrogen and total phosphorus loss in forestland were respectively 6.1, 4.7 and 15.1 times of that in natural state, and nutrient loss was dominated by soluble nutrients. Total amount of loss after reclamation was Natural conditions of 18.1,8.6,27.2 times, and nutrient loss to sediment-bound state-based.