水保所知识产出(1956---)知识库

通过对黄土高原南北样带大面积( 北纬34°05'—40°75'、东经107°14'—111°09') 土壤含水量( 0—500 cm 剖面) 测定和相
应植被类型调查，研究了黄土高原农田、草地、灌木林地和乔木林地4 种土地利用类型土壤含水量的空间变化及它们之间的差
异性。结果表明: 黄土高原4 种土地利用类型的土壤含水量皆呈现南北向地带性变化，自南向北土壤含水量有明显递减趋势，
与多年平均降雨量、潜在蒸散量、土壤质地等的分布具有一致性; 同一地点不同土地利用类型下土壤水分含量具有显著差异
( 农地＞草地＞灌木和乔木林地) ，不同植被类型根系分布、蒸散耗水量的不同是造成含水量差异性的原因。植被建设应遵循土
壤水分分布规律，研究结果对黄土高原植被恢复建设具有一定参考价值。

Soil moisture is a key factor for plant growth and eco-environment restoration on the Loess Plateau，China． The
Loess Plateau is has an arid and semi-arid climate，complicated landforms，and a unique loess-deposition soil environment．
The understanding of zonal pattern in soil moisture under different land use types is fundamental for environmental
mnagement for the selection and plantation of non-native vegetation types． In the present study，a transect with an area of
194000 km2 was selected at the center of the Loess Plateau with a north-south direction to investigate the effects of the
changes in rainfall，potential evaporation，soil texture，and vegetation types on soil moisture． This transect included all
vegetation，soil，and climatic types of the Loess Plateau． Soil moisture profiles of 0—500 cm under farmland，grassland，
shrub land and woodland were measured using the sampling method in 29 counties from the southern to northern Loess
Plateau from July to August 2014． Soil texture，vegetation，slope，slope direction，elevation，latitudes，and longitudes were
also measured． The results showed that: 1) soil moisture under four land use types decreased gradually from the southern tothe northern Loess Plateau with increasing latitude． This corresponded to the distribution of the mean annual precipitation，
potential evapotranspiration，and soil clay texture across the Loess Plateau; 2) soil moisture was significantly different
under different land use types through the comparison of soil moisture in horizontal and vertical directions． The general trend
for the soil moisture was: farmland ＞ grassland ＞ shrub land ＞ woodland． The differences in root distribution and
evapotranspiration under different land use types resulted in the above trend; 3 ) six factors，including mean annual
precipitation，latitude，clay content，sand content，silt content，and potential evaporation，were identified as the main
factors affecting the soil moisture content determined by correlation analysis． The mean annual precipitation and clay content
were identified as the most important factors influencing soil moisture using stepwise regression analysis． Compared with the
clay content，the mean annual precipitation was the main factor determining the spatial variation in soil moisture under
different land use types． This information is useful for environmental managers to ensure ecological restoration on the Loess
Plateau．