滇东南岩溶地区两种地类的水土流失比较

Comparison Between Two Lands of Water and Soil Conservation in Southeastern Yunnan

对西畴岩溶地区坡耕地和封山育林地的水土流失测定结果表明:降雨多少和降雨强度对径流影响较大,一般降雨量多的年份或月份,产生的径流量和泥沙流失量也较多。坡耕地的水土流失情况较为严重,平均每年产生径流170.06t/hm2,土壤侵蚀模数为162t/(km2.a)。封山育林植被恢复后,增加了盖度,减少了土地的裸露,植株对降雨有效截留,有效防止了水土流失,径流量比坡耕地减少了37.30%,土壤侵蚀模数为39t/(km2.a),泥沙的流失量减少75.78%,且呈逐年减少的趋势。封山育林后流失的土壤养分也得到控制,固体养分流失量,分别比坡耕地减少有机质51.79%、全氮70.82%、全磷38.85%、全钾75.36%、速效氮72.10%、速效磷10.75%、速效钾70.21%,液体养分流失量,分别比坡耕地减少氮34.55%、磷23.16%、钾61.31%。封山育林由于有植被的保护,枯枝落叶及微生物对土壤的改良和营养补充,使大多数营养成份有所提高,而坡耕地的土壤营养成份在下降。

The loss of water and soil on slope plowland and enclosure land of the hillside for regeneration in karst areas of Xichou were analyzed, the result shows that the runoff is influenced by the quantity and intensity of rainfall. The quantity of run-off and loss of soil and sand will be produced more when it is more rain. The runoff is 170.06 t/（hm^2·a）, the modulus of soil e roded is 162 t/（km^2·a）. After enclosing land of the hillside for regeneration, forest canopy is increased and bare land is reduced. Trees can effectively withhold rain and prevent loss of water and soil. Compared with slope plowland, the run-off and lose of soil and sand can be reduced 37.3% ,75.78% , the modulus of soil eroded is 39 t/（km^2·a）. It gets less and less year after year. The loss of solid nutrients of soil is reduced as follow, the organic matter 51.79%, total nitrogen 70. 82%, total phosphor 38. 85%, total potassium 75.36%, quick effective nitrogen 72.10%, quick effective phosphor 10.75% and quick effective potassium 70. 21%. The loss of liquid nutrients of soil is dropped down as follow： nitrogen 34. 55%, phosphor 23.16%, potassium 61.31%. When the vegetation has been restored, it is not only reduced loss of nutrient, water and soil, but also increased the nutrient of soil because dead stick and leaves were broken down by microbes. The nutrient of slope plowland is declining at the same time.