| Spatial variability of soil moisture in semiarid areas is the important factor for runoffproducing, and is also an important research contents of the watershed hyrological processes.Soil moisture in the Loess Hilly Region is a limiting factor for the development ofeco-systems, and the spatial distribution of soil moisture is a major reference factor forecological construction and planning. In the present study, the sampling soil moisture of sixtypical transects of the Feng Fu Chuan small watershed in the Loess Hilly Region wasmeasured, And the spatial distribution characteristics and the relationship between soilmoisture and environment factors, such as the topographic data(20m*20mDEM), the averageannual precipitation, temperature, and evaporation and so on, were analyzed. Based on theabove research the soil moisture model was developed and evaluated. The main results asfollows:(1)Through collecting the field soil moisture data of the study area (Feng Fu Chuanwatershed) of in SPSS software conducted the basic statistical analysis of soil moisture dataof the before the rainy season (June2013) and after the rainy season (November2013), andthen obtained a Spatial variation that soil moisture showed increasing trend with soil depthincreasing, and presented a large the overall variability of soil moisture.(2)Based on different resolutions of DEM, the simple topographic factors (slope, aspect)and compound topographic factors-topography humidity index were extracted, contrastedand analyzed the extracted topographic factors (slope, aspect and elevation) of differentresolutions, soil moisture and terrain factors present weak correlation;0to20cm soil depth ofsoil moisture is mainly affected by the aspect with terrain factors; Topography humidity indexwere conducted linear regression with soil moisture, the correlation coefficient of soilmoisture was analyzed in different soil depth. It is concluded that topography humidity indexand soil moisture showed medium and weak correlation through comparative analysis.topography humidity index only reflect the impact of terrain on soil moisture, therefore, otherenvironmental factors (weather, land use type) should be considered that impact on soilmoisture in Loess Hilly Gully Region.(3) the relationship between soil moisture and quantitative factors were analyzed, elevation and soil moisture significantly were correlated on the0.1level, while soil moistureand rainfall was significant linear correlation at the0.05level; spatial variabilitycharacteristics of soil moisture with different qualitative factors (slope position, slope, landuse type) were studied, Soil moisture of mesa is the most highest while the hilly top lowest;Soil moisture distribution in different slope downward, soil moisture in the shady (northeast,east, southeast) is higher than in the sunny (west, southwest, south), mainly due to strongsolar radiation received sunny, meanwhile the soil evaporation is more large; For differenttypes of land use, soil moisture content in the order: ditch mesa> orchard> slope farmland>terrace> grass>mixed forest> shrub. The Spatial variability of soil moisture at the above studyprovides scientific theory for water management and restoration of natural vegetation andartificial vegetation rational selection and configuration in the Loess Plateau.(4) The two theoretical models of soil moisture and environmental factors were buildedby multiple linear regression and curve weighting methods, and the simulation accuracy wascompared, the result showed that the weighted quadratic model of the Feng Fu Chuanwatershed is the optimal model, the model can better reflect the variation of soil moisture andenvironmental factors. |
