抚仙湖流域磷矿开采区不同植被对地表径流控制研究

Control of Different Vegetation on Surface Runoff Volume in Phosphorus Ore Mining Areas of Fuxian Lake Watershed

依区域年降雨量的差异,将抚仙湖磷矿开采区年降雨量分别为1 200～1 300 mm和1 000～1 100 mm的区域划分为东大河流域磷矿区和帽天山磷矿区两个研究单元,通过设置野外径流小区,在自然降雨状态下对矿山废弃地产流及矿区现有主要植被类型对地表径流量的控制进行比较研究.研究结果表明:降雨强度是矿山废弃地产流的关键因子,在大雨状态下矿山废弃地径流量远大于各植被类型,降雨历时是影响各植被类型地表径流的关键因子,各植被类型产流量各不相同;径流量大小与植被总盖度、土壤总孔隙、土壤最大持水量、土壤有机质含量、地表凋落物厚度及重量呈负相关;各植被类型总径流量次序为:灌草丛＞云南松灌丛＞云南松＞混交林＞华山松林＞竹林＞桉树林,除灌草丛外矿区现有植被类型均能对降雨径流取到较强的截流作用.

According to the difference of the annual rainfall volume,the phosphorus ore mining area of Fuxian Lake is divided into two research units: Dongda river watershed region(1 200-1 300 mm) and Maotian mountain region(1 000-1 100 mm).Through the field observation zones,a comparison is made on the runoff volume of discarded mine land and mine area with major types of vegetation under the condition of natural rainfall.The results indicate: rainfall intensity is a key factor causing runoff in discarded mine land;the surface runoff volume of discarded mine land is far larger than areas with vegetation under heavy rain;rainfall time is a key factor influencing surface runoff volume of each area with vegetation,and the runoff volume of areas with different vegetation is different;runoff volume is inversely proportional to the total plant coverage,total porosity,maximum waterholding capacity,and organic matter content of the soil,thickness and weight of litter on the earth's surface.The order of total runoff volume for each vegetation species is: shrub-grass land > clump of Pinus yunnanensis> Pinus yunnanensis woods >Mixed forest >Pinus armandii woods>bamboo woods> eucalyptus woods.Except shrub-grass,all the present vegetation species can detain rainfall runoff effectively.