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

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/（hm2·a）,the modulus of soil eroded is 162 t/（km2·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/（km2·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.