| The Loess Plateau, which is located at the northwest of China with the total area of 640 thousand km2 including 7 Provinces or autonomous regions, such as Qinghai, Gansu, Ningxia, Shaanxi, Inner Mongolia, Shanxi and Henan, is the one region of the most severe soil erosion and fragilest eco-environment in China and even in the World. The natural conditions in the Loess Plateau are the crashed landforms, loosening soil textures, sparse vegetations, drought climate, concentrated rainstorms, rich natural resources with frequent natural disasters. To control soil erosion and better the eco-environment in the region is the essential way to realize the sustainable development between human and nature in harmony. To restore or rehabilitate the everlasting, stabilizing and high efficient vegetation ecosystems are the importance viscera for the eco-environmental construction in the region. The regional water resources' carrying capacity and its' environmental capability is the limited factors related to the success or failure of vegetation construction. In the southern Loess Plateau, the 'five water' (such as atmospheric water, surface water, soil water, ground water and botanical water) transfer or cycling, water budget elements, temporal and spatial changes of soil water contents, water resources using patterns and its' efficiency, water resources' carrying capacity and its' environmental capability for the regional vegetation construction under the SPAC in the ecosystems of Chinese pine, arborvitae, black locust, apple, apricot, farming field and grassplot have being completely and systematically studied under the five levels of tissues, organs, individuals, communities and ecosystems by the water budget field, run-off observation field and original state soil column. The main results were made to draw the following conclusions:When the atmospheric rainfalls above the Chinese pine, arborvitae, black locust, apple and apricot stands in the southern Loess Plateau are among 0.8-1.0mm, its are completely absorbed by the canopies, then there markedly are positive relations between the atmospheric rainfalls and canopy penetration rainfalls. During the plant growing seasons from April to September, the canopy penetration rainfall rates of the Chinese pine, arborvitae, black locust, apple and apricot stands were 73.8%, 76.9% , 79.5%. 79.3% and 78.9% separately, its were higher with lower density and canopy density, the rates of the broad-leaves plantations were higher than the coniferous plantations, so were the change ranges of the rates. The average interception rates for the atmospheric rainfalls of the Chinese pine, arborvitae, black locust, apple and apricot stands were 20.0%, 16.9%, 15.5%, 15.6% and 14.1% separately, and its' were higher in the coniferous plantations than in the broad-leaves plantations, so were the change ranges of the rates. When the atmospheric rainfall above the Chinese pine, arborvitae, black locust, apple and apricot stands were among 1.0-1.2mm, its were completely absorbed by the stem run-off, then the stem run-off rainfalls increase with the atmospheric rainfalls in evidence, the stem run-off rainfalls of the Chinese pine, arborvitae, black locust, apple and apricot stands were 6.1%, 6.2%, 4.9%, 5.0% and 6.9% separately, it changes with stand types, former precipitation and raining intensity. The stem run-off rainfall is very importance meaning to reinforce soil water resources in the drought region or months. The maximum litter holding water rates of the Chinese pine, arborvitae, black locust, apple and apricot stands were 309.28%, 321.34%, 392.37%, 345.53% and 352.78% separately, their maximum litter holding water amounts were 1.34, 1.21, 1.73, 0.25 and 1.23 mm separately. The standing litter biomass of the five stands were 4.234, 3.885, 4.924, 0.563 and 3.581 t hm-2 separately, and the average holding water rates were 4.90%, 4.90%, 6.02%, 0.84% and 5.55% separately. The more the litter accumulates in the stands, the more it holds back the atmospheric precipitation. The litter holds more back theatm...
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