Analysis Of The Features Of Soil Moisture And Water Conservation For Different Woods And Lands In The Southern Slope Of Qilian Mountain

Soil is an essential part of ecosystem and important material basis of woods.The water regime is one of the important indicators of land quality assessment.Forest soil,which can be regarded as the material basis of the living woods,is the major ponding of water conservation in the forest ecosystem.It has distinct water regime because it is affected not only by the special biota under forest vegetation but also by the tree roots and forest litter.Previous studies on forest water conservation are mainly concentrated on northern slope of Qilian Mountain other than southern slope of Qilian Mountain.This paper mainly presents water retention and conservation for different woods and lands in the southern slope of Qilian Mountain.The results can be concluded as follows:(1)The research result shows that the soil water content of different woods and lands presents a decreasing trend along with the increase of soil depth.As for the different soil depths,the result is Picea crassifolia>Potentilla fruticose>Sabina przewalskii,and Caragana jubata changes between the three ones.On the whole,the result is Picea crassifolia>Potentilla fruticosa>Sabina przewalskii,and Caragana jubata and Potentilla fruticosaare are almost the same in soil water content.The soil porosity of different woods and lands decreases basically along with the increase of soil depth,thus it can be seen that the vegetation and litter on the soil surface can increase the soil porosity.While viewing from different soil depth and the whole aspects,the result can be regarded as Picea crassifolia>Sabina przewalskii>Potentilla fruticosa>Caragana jubata.The soil bulk density,specific gravity of different woods and lands increases basically along with the increase of soil depth,and the result is Caragana jubata>Potentilla fruticose>Sabina przewalskii>Picea crassifolia while viewing overall from different soil depth.(2)The soil water content shows recovery because it has capillary root at 20-40 cm of tree root.The soil water content of Sabina przewalskii is obviously less than the other forest lands as it usually germinates on sunny slope.The root system of surface layer vegetation comes from deep soil with larger soil porosity and smaller volume-weight.The soil porosity also decreases along with the increase of soil depth and volume-weight increases even at 30 cm of tree root.Compared with shrubberies like Potentilla fruticosa and Caragana jubata,the arbors like Sabina przewalskii and Picea crassifolia root development,larger in soil porosity and volume-weight are also smaller.So the soil porosity and volume-weight results out the root development and numbers of capillary root.(3)The main factor which can influence the soil moisture content is forest land types,while the soil depth is the secondary factor.Except Sabina przewalskii,the other three land types of the correlation of soil porosity,volume and specific gravity with soil depth are relatively more obvious,the correlation of water content with soil depth is relatively worse,and the correlation of porosity and volume-weight with soil depth are almost the same.(4)The research result shows that the soil water storage of different woods and lands presents a decreasing trend along with the increasing of soil depth,thus it is obvious that the vegetation and litter on the soil surface can increase the soil water storage capacity.On the aspect of soil depth and the whole,the result is Picea crassifolia>Sabina przewalskii>Potentilla fruticose>Caragana jubata.As for the forest litter effective dammed-up content and water content of different forest lands,the result is Caragana jubata>Picea crassifolia>Sabina przewalskii>Potentilla fruticosa.The result of the total soil water content is Caragana jubata>Sabina przewalskii>Picea crassifolia>Potentilla fruticosa.The result of the total soil water storage of different land woods is Picea crassifolia>Sabina przewalskii>Caragana jubata>Potentilla fruticosa.The water conservation function gives priority to soil layer and the soil water storage in the soil layer accounts for 96% of the total.It turns out that the soil water conservation function of Picea crassifolia is the strongest in the southern slope of Qilian Mountain.