青海湟水河流域不同退耕还林模式水土保持效应

Effect on Soil and Water Conservation from Different Models of Conversion of Farmland to Forest in Huangshui River at Qinghai

基于野外定点观测资料收集和室内实验分析,研究了青海湟水河流域不同退耕还林模式下水土保持效应,结果表明:41 a青杨>41 a云杉>天然次生灌木林>9 a云杉沙棘混交>9 a沙棘>9 a云杉(坡位下)>9 a云杉(坡位上)>4 a云杉沙棘混交>农田。同时对照农耕地土壤:退耕还林地土壤理化性质和生物特性在退耕5 a后有明显变化,天然次生灌木林稳渗率>9 a云杉沙棘混交>4 a云杉沙棘混交>农田;土壤可蚀性因子从农耕地的0.773减少到次生灌木林的0.483;41 a青杨枯落物单位面积有效蓄水量是41 a云杉的2.6倍。

Based on field investigation and experimental data,soil and water conservation effect was studied in Huangshui river at Qinghai province.The results showed that the sequence of water and soil holding capacity is 41 a Populus cathayana〉41 a Picea crassifolianatural scrub forest〉9 a mixture of Picea crassifolia and Hippophae rhamnoides〉9 a Hippophae rhamnoides〉9 a Picea crassifolia（lower slope）〉9 a Picea crassifolia（upper slope）〉4 a mixture of Picea crassifolia and Hippophae rhamnoides〉farmland.Campared with farmland soil,after 5 years of conversion of farmland to forest,the index of physical and chemical characters and microbial characteristic in soil,takes on obvious changes,and it is stable infiltration velocity of natural scrub forest〉9 a mixture of Picea crassifolia and Hippophae rhamnoides〉4 a mixture of Picea crassifolia and Hippophae rhamnoides〉farmland.And soil erodible factor,K is determined to 0.483 in natural scrub forest from 0.773 in farm.And water holding of little per unit of 〉41 a Populus cathayana was 2.6 times than that of 41a Picea crassifolia.