单 位：
北京林业大学林业生态工程教育部工程研究中心;北京林业大学水土保持学院
关键词：
陡坡地;土壤水分;微地形;垂直变化;陕北黄土区
摘 要：
土壤水分是陕北半干旱黄土区植被生长最主要的限制因子,然而受坡面微地形的影响,黄土坡面土壤水分存在异质性,从而影响林草植被精准配置。为此,本研究通过对黄土高原5类陡坡微地形土壤含水量(0~180 cm土层)的定位监测数据,分析研究不同降水年型条件下土壤水分的变化特征及其对微地形的响应。结果表明:1)降水年型对微地形土壤水分时空变化均有影响,枯水年切沟底土壤含水率季节变化平缓,雨季前下降趋势缓慢,雨季后增长趋势滞后;而丰水年切沟底土壤水分的变化呈V型变化;缓台、浅沟、塌陷和陡坎4种微地形枯水年土壤水分季节变化一致,呈M型变化;而丰水年土壤水分季节变化呈W型,2个最低值出现在5月和11月。2)垂直方向上塌陷、原状坡、陡坎土壤水分自上而下呈先减小后增大的趋势,缓台、浅沟、缓坡呈先增大后减小的趋势,黄土陡坡中的切沟底土壤水分含量最高。3)缓台、陡坎、原状坡的土壤水分速变层和活跃层在丰水年消失,在枯水年深度下移;塌陷、切沟、浅沟、和缓坡土壤水分速变层和活跃层在枯水年均下移。
译 名：
Response of soil moisture to micro-topography of steep slope in the Loess Plateau,northern Shaanxi
作 者：
DU Shengli;ZHU Qingke;WANG Xuhu;LIU Shuqin;Beijing Forestry University,Engineering Research Center of Forestry Ecological Engineering of the Ministry of Education;College of Soil and Water Conservation,Beijing Forestry University;
关键词：
steep slope;;soil moisture;;micro relief;;vertical variation;;the Loess Plateau
摘 要：
[Background] Soil moisture is one of the main factors that restrict vegetation growth,vegetation restoration and stand stability in the Loess Plateau of China. It also shows obvious space-time characteristics under different land use,topography and geomorphology and vegetation condition due to the effects of rainfall factor,surface run off,plant transpiration,root absorption and so on. Soil moisture variation research at steep slope is the important premise of vegetation construction reasonable allocation.In the Loess Plateau of China,soil erosion has led to severe soil quality degeneration and it is important to assess the soil quality of micro-topography. Thus,the study of soil moisture in vertical profiles has important significance for understanding the utilization of soil moisture in artificial forests. The aim of this study was to investigate the distribution and the hierarchical character of 0-180 cm layers soil moisture in vertical profiles. [Methods] The study investigated not only micro-topography soil moisture content of steep slope,but also the effect the micro-topography soil moisture spatial and temporal distribution characteristic which is influenced by different precipitation years. The results showed that the differentprecipitation years have a great deal of effect on the micro-topography soil moisture. [Results] 1) Soil moisture content grow in step with precipitation in high flow years,and the annual soil moisture changing curve of gully is very closed to the "V"shape among high flow years; however,soil moisture content grow in delay two months with precipitation in low flow years; the annual soil moisture changing curve is very closed to the "M"shape among high flow years,of which the peak value was presented in March and August; 2) In the perpendicular direction of the steep slope,soil moisture content of the gully,original slope and scarp first decrease and then increase with depths increasing,on the contrary,soil moisture content of the platform,collapse and gentle slope first increase and then decrease with depths increasing,in addition,soil moisture content of scarp is very well,which moisture better than not only platform,gully and scarp,but also original slope and gentle slope; 3) Fast changing layer and active layer of soil moisture was displayed in turn in low flow years,such as collapse > gully > original slope > shallow gully > gentle slope > platform > scarp,of which soil moisture of the collapse is very well. Fast changing layer and active layer of soil moisture gradually disappear in high flow years,on contrary,the fast changing layer and active layer of soil moisture gradually move down with depths increasing in low flow years.[Conclusions]In order to increase the survival rate of afforestation,promote the quick restoration of forests and grass for soil and water conservation,it was suggested that the collapse can carry trees; and gentle slope and platform of steep slope can carry shrub and original slope and shallow gully of steep slope can carry herbaceous plant. Besides,It is difficult for plants to grow in scarp of steep slope,In particular,collapse of steep slope can carry the tall arbor tree.
