围栏封育对荒漠草原灌丛草地土壤优先流的影响研究

Study on the Effect of Grazing and Enclosure on the Preferential Flow of Soil in Desert Grassland and Shrub Grassland

为探究围封对灌丛草地土壤优先流的影响,以宁夏吴忠市盐池县典型荒漠草原区为研究区,通过野外入渗染色试验、图像处理分析等方法,对围封荒漠草原灌丛草地土壤优先流的影响进行评价。结果表明:(1)围栏封育与放牧管理样地土壤水分入渗特征存在差异,在围栏封育样地,草地、天然柠条林地、人工柠条林地的入渗染色图像分别在0—125,0—115,0—105 cm呈现均匀分布,而在125—240,115—150,105—140 cm呈现染色分支,在放牧管理样地,草地、天然柠条林地、人工柠条林地入渗染色图像分别在0—80,0—70,0—80 cm呈现均匀分布,围栏封育导致土壤优先流发生深度更大;(2)土壤剖面染色面积比表现为围栏封育草地>围栏封育天然柠条林地>围栏封育人工柠条林地>放牧管理人工柠条林地>放牧管理天然柠条林地>放牧管理草地,土壤染色深度表现为围栏封育草地>围栏封育天然柠条林地>放牧管理草地>放牧管理天然柠条林地>围栏封育人工柠条林地>放牧管理人工柠条林地,围栏封育管理会导致土壤剖面染色面积比及染色深度增大;(3)土壤优先流变异系数表现为放牧管理天然柠条林地>放牧管理人工柠条林地>围栏封育天然柠条林地>放牧管理草地>围栏封育人工柠条林地>围栏封育草地,放牧管理导致土壤优先流程度增加,而围栏封育降低灌木林地及草地的优先流程度。因此,在荒漠草原等干旱半干旱地区,围栏封育可作为提升土壤水分均匀入渗深度、降低优先流发生程度、提高土壤水分利用效率的重要管理方式。

In order to explore effect of the enclosure of shrub grassland on soil preferential flow,typical desert area in Ningxia province,Wuzhong city was taken as the study area,field infiltration dyeing test and image processing analysis were used.The results showed that:(1)In the fenced and enclosed plots,the infiltration staining images showed obvious difference.In the fenced and enclosed plots,grassland,natural Caragana korshinskii forest and artificial C.korshinskii forest showed uniform distribution at 0-125,0-115 and 0-105 cm,respectively,and branching at 125-240,115-150 and 105-140 cm.While in the grazing management plots,the infiltration staining images of grassland,natural C.korshinskii forest and artificial C.korshinskii forest showed uniform distribution in 0-80,0-70 and 0-80 cm,respectively.The depth of soil preferential flow was deepened due to fencing.(2)The area ratio of soil profile staining was as follows:fenced grassland>fenced natural C.korshinskii forest>fenced artificial C.korshinskii forest>grazing management artificial C.korshinskii forest>grazing management natural C.korshinskii forest>grazing management grassland.The depth of soil staining was as follows:fenced grassland>fenced natural C.korshinskii forest>grazing managed grassland>grazing managed natural C.korshinskii forest>fenced artificial C.korshinskii forest>grazing managed artificial C.korshinskii forest.Fenced management would lead to the increase of soil profile staining area ratio and depth.(3)Soil preferential flow variation coefficient of performance was as follows:grazing management natural C.korshinskii woodland>grazing management artificial C.korshinskii>enclosure cultivating natural C.korshinskii woodland>grazing management grassland>grazing management cultivating artificial C.korshinskii forest land>enclosures fence grassland.Grazing management will lead to increment of soil preferential flow.Cultivating and enclosures will reduce the degree of preferential flow shrub forest and grass.Therefore,in arid and semi-arid areas such as desert steppe,fencing can be an important management method to improve the uniform infiltration depth of soil water,reduce the occurrence of preferential flow,and improve the efficiency of soil water use.