滇中高原山地防护林体系水土保持效益研究

以小流域为单元 ,根据山地防护林体系配置的特点 ,采取定位和半定位研究方法 ,分层次对山地防护林体系蓄水保土功能进行监测分析。研究结果表明 :不同地类及用地方式 ,不同森林类型保持水土效益差异较大 ,在滇中高原 ,裸地和坡耕地是流域产沙的主要来源 ,农耕地侵蚀量是林地的 18.7～ 36 .0倍 ,裸地侵蚀量远大于坡耕地 ,高达林地的 10 0倍左右 ;营建防护林体系后 ,防护效益显著 ,土壤侵蚀模数随森林覆盖率的增加而减少 ,流域森林覆盖率由 18.6 %上升到 42 .4%时 ,土壤侵蚀模数减少 36 % ;坡地造林后 ,地表径流减少 79.44 %～ 96 .9% ,泥沙削减 87.8%～ 99.9% ;要使山地小流域水土流失得以控制 ,森林覆盖率必须达到 30 %以上

Soil and Water Conservative Effect of Protection Forest System in Plateau and Mountainous Region of Central Guizhou Province

Taking small watershed as a unit, according to the allocating feature of mountainous protection forest system, and adopting locating and semi-locating research technique, the function of wat er accumulation and soil conservation of mountainous protection forest system was monitored and analyzed in hierarchical way. The research results are as follows. The difference of soil and water conservative effect is relatively la rge in different land types, different land use methods and different forest types. The main source of sand producing is the bar e area of central Guizhou plateau and cultivated slopeland in drainage a rea. The erosion quantity of cropland is 18.7～36.0 t imes than that of forest land; The erosion quantity of bare land is far larger than that of cultivated slopeland, and i s as high as about 100 times than that of forest land. After the protection forest system was established, the protection effect was ob vious, the modulus of soil erosion reduced following the increase of forest cover rate; The modulus of soil erosion decreas ed 36% when the forest cover rate of drainage area increased from 18.6% to 42.4%. After the construction of plant ation in sloping field, the surface runoff decreased from 79.44% to 96.9%, and the silt amount decreased from 87.8% to 99.9%; In order to control soil and water loss of small watershed in mountainous region, forest cover rate must be more th an 30%.