Soil Water Characteristics Of The Economic Forest In The Gully Region Of Loess Plateau

The soil water is the major restrictions for plant growth and development in the Loess Plateau. It has practical and scientific significance to study the dynamic change of soil water. Based on measuring soil water content of apricot forests in the loess gully region, the temporal-spatial changes of soil water was studied, and the meet degree of soil water to apricot growth was analyzed with the help of moisture niche-fitness model. The result showed that:1.Rainfall is the main factor affecting soil water change in Loess hilly-gully region,the change of soil water was hysteretic relative to rainfall. the change of soil water was fluctuant from 2008-2009.2. The annually seasonal dynamics of soil moisture were divided into four stages which were relatively stable period in the initial stage of growing season, intensive consumption period in the middle stage of growing season, recovery compensation period in the middle stage of growing season, and slowly evaporation period in the late stage of growing season. Soil water content was vertically divided into three layers: faint utilization layer, utilization layer, and adjustment layer.3. In vertical change,soil profile of terracefield can be divided into 3 levels:soil waterfaint utilization layer (0—20cm), soil water of which changed greatly affected by rainfall,evaporation and crop utilization,and mostunstably.Soil waterutilization layer (20—200cm),which was main distribution and wateraccepting layers of crops and vegetation roots,and was main water-supplying sources and water reservoir of crops and vegetation growth,soil water changed disorderly affected by crops roots.Soil water adjustment layer (beyond 200cm),which was distribution layer of crops deep roots,the amount of soil water changed a little.4. Average water niche suitability in land of Juglans regia L.was greater than that in land of Diospyros kaki L., which was greater than that in land of Armeniaca vulgaris Lam.,which was greater than that in land of Zanthoxylum bungeanum Maxim, which was greater than that in land of Prunus armeniacia sibirica.5. Water supply-demand in walnut land was harmonious the whole year, the water supply was almost entirely less than water consumption spanning the growing season in other ecnomic forest lands. As a result, there was water deficiency in these lands, the supply protruding contradicted the consumption.