苏南丘陵区不同土地利用状况的蓄水保土功能研究

Study on the Function of Soil and Water Conservation for Different Land Use in Hilly Region of South Jiangsu

通过对试验区水平梯田、杉木林和裸地三种不同处理地段水土流失状况的定位观测．以及地表径流水水质和土壤理化性状的分析．认为水平梯田和茂密的林木覆被他表，不仅大大减低土壤侵蚀量．而且能降低土壤物质的流失量。据研究，水平梯田和杉木林区的年土壤侵蚀模数分别为荒波对照区的2.4％和4.01％，年地表径流系数分别为对照区的42．3％和32．3％；梯田区氮、磷、钾和有机物质的流失量分别比对照区低67．26％，70．49％，66．4％和95．57％；杉木林区分别比对照区低72．07％，77．02％，43．18％和90．7％。此外，水平梯田和杉木林地对滞洪和减洪、增加土灌入沙方面也有重要作用，其产流时间比对照区迟30～50min，洪峰流量减低200％～300％。

On the basis of orientative observation of the soil and water loss on 3 plots (terraced field,Chinese fir plantation and bare spot),and the analysis of surface runoff water quality and soil characteristics, it is believed that building terraced field and planting trees on the sloping tillage field can decrease not only the (luantity of water and soil loss,but also the loss of nutrient matter from soil. The modulus of soil erosion on the horizontal terraced field and Chinese fir plantation are 2. 49% and 67. 7% than that on the bare plot. The loss of N, P, K and organic matter on the horizontal terraced field is 67. 26 9%, 70. 4%, 66. 4% and 95. 57% lower than that on the bare plot, and also the loss of N, P, K and organic matter on Chinese fir plantation is 72. O7 %. 77. 02 %. 43. 18 % ,and 90. 7 % lower than that on the bare plot. Moreover,the time of surface runoff on the horizontal terraced field and Chinese fir plantatios is held up by 30 min as compared with bare plot, and the flooding quantity on the flood peak will decrease 2 to 3 times.