Soil moisture curve is elementary curve that shows the relation between potential energy and the content ofwatersoil and analyses retaining and transporting in soil water belt.
The density of the Pinus tree-belt at the dune site should be paid special attention to because soilwater holding capacity was poorer at this substrate;
由于沙丘土壤的保水性差，即使在夏秋雨季也不能有效保持水分，因此，沙丘油松林带应注意密度控制。
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One of black soil belts in the world runs through Yi'an , which brings the fertile soil, rich water and flourishing grass to the county and becomes the best belt to breed milk cows.