晋北黄土丘陵区不同林草措施的蓄水保土和土壤水分效应研究

以设在山西省阳高县的大型径流观测场为依托,以2005-2009年的野外实测数据为依据,研究了晋北黄土丘陵区人工植被与鱼鳞坑配合的蓄水保土及土壤水分效应,并与荒坡、苜蓿地进行了对比。结果表明:在观测的5年内,柠条、沙棘、油松的蓄水保土能力随种植年限延长无明显增加趋势,但鱼鳞坑的蓄水能力和保土能力分别高达84.7%～96.0%和95.2%～99.7%;荒坡和苜蓿(Medicago sativa)第一年和第二年的蓄水保土能力较差,第三年和第四年随植被盖度增加能力急剧增强,第四年蓄水能力分别达82.8%和91.2%,保土能力达97.0%和98.0%;土壤水份分析结果表明:不同小区4～9月土壤水分变异系数为7.0%～19.1%,油松区变异系数最大,其次为沙棘、苜蓿和柠条区,荒坡区和裸坡区变异较小,不同小区土壤水分亏缺率为23.98%～52.66%,亏缺顺序为柠条区>苜蓿区>油松区>沙棘区>荒坡区>裸坡区;林草植被有效地减少了水土流失,亦增加了土壤水分的变异及亏缺程度,应注意林草植被的合理选择和配置。

Effect of different forest and grass vegetation on soil and water conservation and soil moisture in Loess hilly area in Northern Shanxi Province

Based on the runoff plots located in Yanggao County,Shanxi Province and the field data observed in 2005-2009,effects of different forest and grass vegetation,including fish-scale pit Caragana Korshinskii,fish-scale pit Hippophae rhamnoides,fish-scale pit Pinus tabulaeformis,wasteland and Medicago sativa on soil and water conservation and soil moisture in Loess hilly area in northern Shanxi were investigated.The results showed that compared with bare land,forest and grass vegetation could control soil and water losses effectively,Caragana Korshinskii,Hippophae rhamnoides and Pinus tabulaeform combined with fish-scale Pit reduced the runoff by 84.7%-96.0% and reduced sediment by 95.2%-99.7% during 5 years,effects of wasteland and Medicago sativa on soil and water losses increased effectively from the third and fourth years,with the runoff reduction rate of 82.8% and 91.2%,and the sediment reduction rate of 97.0% and 98.0% respectively in the fourth years;Coefficients of variation(CV) of soil moisture were ranged from 7.0-19.1% in different vegetation plots from April to September,and that of Pinus tabulaeform plot was the highest,Hippophae rhamnoides,Medicago sativa and Caragana Korshinskii were following,and wasteland and bare land were lower.Deficiency rates of soil water were ranged from 23.98%-52.66%,that were in the order Caragana Korshinskii > Medicago sativa > Pinus tabulaeform> Hippophae rhamnoides >wasteland> bare land.Implying vegetation could decrease soil and water loss efficiently,also increase the variation and deficiency of soil moisture.