珠江源头区占马地小流域不同用地水土保持作用研究

 对珠江源头区占马地小流域灌木林地、疏林地、耕地及荒草地4类不同用地的土壤含水量、理化性状、土壤侵蚀特性等进行测定分析,结果表明:1)在土层60 cm深度范围内,随着土层的加深,灌木林地和疏林地的土壤水分含量呈下降趋势,而耕地和荒草地则呈上升趋势。2)土壤在持水能力、通透性能等方面排列顺序是灌木林地>荒草地>疏林地>耕地;土壤有机质含量以荒草地最高,为2.34%,分别是灌木林地、疏林地和耕地的1.08、1.89和3.46倍;全氮含量顺序是荒草地>灌木林地>疏林地>耕地;全磷和全钾含量顺序是疏林地>荒草地>灌木林地>耕地。3)不同用地的初渗速率、稳渗速率与渗透系数均为灌木林地最大,荒草地最小,灌木林地的稳渗速率、渗透系数分别是耕地、疏林地、荒草地的1.142、.06和2.7倍。4)不同用地的土壤最大持水量,在020cm土层,排列顺序为耕地>灌木林地>疏林地>荒草地;在2060cm土层,则为疏林地>灌木林地>荒草地>耕地。5)在坡度相同的情况下,不同用地的降雨产流时间为荒草地>疏林地>灌木林地>耕地;地表径流量为荒草地>疏林地>灌木林地>耕地;土壤侵蚀量以耕地最大,分别是灌木林地、疏林地和荒草地的2.51、2.26和1.32倍。研究结果可为珠江源头区土地合理利用提供理论依据。

Soil and water conservation action of different land use in Zhanmadi small watershed in source area of Pearl River

The soil of different land use including shrub land,open forest land,farmland and grassland in Zhanmadi small watershed in source area of Pearl River were investigated.The results indicated that: 1) Inside soil depth 60 cm,as the soil depth increased,the soil water content of shrub land and open forest land were decreased,the case of that on farmland and grassland was in the opposite direction.2)The content of organic matter of soil of grassland was 2.34%,that was the highest,and was 1.08,1.89 and 3.46 times as much of that in shrub land,open forest land and farmland respectively.The content of nitrogen was in the order of grassland >shrub land >open forest land >farmland,the content of phosphorus and potassium was in the order of open forest land >grass land>shrub land>farmland.3) As far as soil hydroscopic water and soil permeability were concerned,the order was shrub land > grassland > open forest land > farmland.4) The started water penetration rate and stable water penetration rate of shrub land were the highest,which were 2.06 times,1.14 times and 2.7 times as much of that in open forest land,farmland and grassland respectively.That implied among the four land use types,the soil permeability of shrub land was the best,next came farmland and open forest land,that of grassland was the lowest.5) In 0-20 cm soil layer,the maximum water-holding capacity was in the order of farmland > shrub land > open forest land > grassland;in 2040 cm soil layer,the order was open forest land > shrub land > grassland > farmland.The water yield time started by grassland at first,next came open forest land,shrub land and farmland.