| Slope in barren hills has a low rate of vegetation coverage, poor soil and water conservation and easy to erosion, and it is an important part in ecosystem construction of Beijing,and also an important component of mountain area ecosystem construction. Therefore how to use of soil water reasonable and effectively becomes the key to insuring water vegetation needs and the improving the ecological environment. In light of existing vegetation rehabilitation in this area of scientific issues, which has taken soil water the key limiting factor in vegetation which has as into the starting point of through natural rainfall conditions, Choose 15°and 25°slope to set Bromus riparius test plot, and take bare places as comparison, observe the biological characteristics of brome and slope rainfall infiltration, runoff and soil moisture dynamic variation, research Bromus riparius on hill slope soil moisture changes, the main conclusions are as follows:1. Planting Bromus riparius for 4 years in 15°slope in Beijing the amount of aboveground biomass can up to 4967.3 kg/hm2,while 0 ~30 cm below-ground biomass was 3941.4kg/hm2, and underground biomass of 0 ~ 10cm is major part of underground water and soil conservation. Slopes has significant effect on the up-ground and has nothing with on the underground biomass ; Grass harvesting treatment on the ground and underground biomass have a certain role in promoting growth.2. Planting of Bromus riparius can significantly increase soil infiltration rate, and to prevent from soil erosion, and its water-retention capacity was 94.2%. Slope on earth surface runoff has no significant effect with it; Grass cutting will reduce the soil infiltration rate, thereby to increase the Bromus riparius slope surface runoff, but has little effect on annual runoff depth; Bromus riparius different plant spacing on plant height no significant effect on the cover, but significantly affect the depth of annual runoff. The higher density, the more obvious soil erosion control effect was.3. The period of soil dynamic moisture 15°slope in Beijing, are more obviously between March to September, in which, it can be divided into the early rainy season (March ~ June) soil moisture continued to decline and rainy season (July to September) the soil moisture content increased gradually phase, which pre-rainy season, low soil moisture and Bromus riparius can slow down the slope of 0 ~ 60cm depth soil water content decreasing , and play the role of the largest to the 0 ~ 20cm soil layer to maintain soil water content between 13.3% ~ 14.6%; rainfall significant increase during the rainy season, Bromus riparius hill slope can contribute to achieve a relatively high status of soil water absorption, and after 16% of soil water content, the acceleration of 0 ~ 60cm soil layer, in particular with 0 ~ 20cm layer of soil water loss, can maintain soil water content under 13.4%; gradient changes and cutting treatments on Bromus riparius dynamic changes of soil moisture had no obvious effect; Bromus riparius spacing change has some effect on soil Dynamic changes of water, reasonable density of planting the slope of the dynamic changes of soil moisture plays an important part and the slope to 30cm for the spacing on the slope planted Bromus riparius best soil and water conservation in Beijing.4. Under the conditions of saturated water, evapotranspiration increase and then decrease for grassland and bare land with different density as the extension of time, in which, evapotranspiration of bare soil column is the least, evapotranspiration of brome increase with grass planting density. When the soil moisture is saturated, Bromus riparius can accelerate the loss of soil moisture .
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