Soil moisture characteristics of walnut forest land in Weibei Loess Plateau
FAN Jin-Quan-；Chen-Yuan-Guo
1.Northwest Sci-Tech University of Agriculture and Forestry, 712100, Yangling, Shaanxi;2.College of Soil and Water Conservation, Beijing Forestry University, 100083, Beijing; 3.East China Normal University, 200062, Shanghai; 4.Zaozhuang Normal College, 277160, Zaozhuang, Shandong: China
Abstract：Water is a crucial limiting factor for the eco-environmental restoration and economic development in the Loess Plateau. That has practical and scientific significance to study the dynamic law of soil moisture. Based on random design and field experiments, the soil moisture condition and its changing law of walnut forest land were studied. The results showed that soil evaporative capacity of walnut forest land was positive correlation to average temperature of month. Precipitation, soil evaporation and plant transpiration were the primary factors affecting soil moisture which variation with time. The seasonal change of soil moisture in growing period of walnut was divided into three stages, excessive consume period in late spring and beginning summer (from May to June), supply period in rainy season (from July to October) and slow accumulation period in winter and spring (from November to April in next year). The seasonal change of soil moisture had closed correlation to seasonal change of precipitation. The water amount of soil in walnut forest is the highest in August and lowest in June. The water consume amount of which is the ighest in July and lowest in April. As to soil moisture profit and loss, it is in a deficient condition from April to July, and supplemented from August to October with rainfall increasing. Soil moisture could be improved and water scarcity could be decreased in a certain degree through water regulation. To amount of soil moisture consume, which was increased under different irrigation treatments, while decreased in a certain degree under covering membrane, covering grasses and pruning. In a word, the effects of covering membrane, covering grasses, pruning in a moderate level and irrigation (225?kg in April, 225?kg in June) were better than others. Especially the effect of covering membrane was the best, not only soil moisture was increased, the exhausting was increased and the growth of development was promoted, but also cost of which was cheap, gained easily and used expediently. It was suggested that the measure of covering membrane should be popularized in high yield cultivation of cash forest in loess plateau.
2005, Vol. 3 
