Response Of The Main Tree Saplings To Different Soil Moisture Conservation And Water Stress In Interlaced Zone Of Mountain Forest And Arid River Valley

Four native tree species had been cultivated by setting different soil moisture conservation in arid valleys of the Minjiang River for 2 years. Soil moisture, plant physiology, biochemistry and growth had been analyzed to explore the response of the main tree species to drought adversity in arid valleys and provide theoretical and technical guidance for the ecological restoration of this area. The results are as follows:1. Comprehensive evaluation of drought resistance of each tree species. The indicators of each tree species were different at the same growth condition. And the drought resistance was analyzed by the method of principal component analysis,the result showed that the ability of drought resistance about the 4 native tree species was as follows: Cupressus chengiana>Pinus tabulaeformis>Locust>Ulmus.2.The change of soil moisture.The soil moisture in the layer of 0-30cm, compared to the control, had been increased respectively after soil moisture conservation.The increase amplitude of rhizosphere soil moisture was as follows:weed mulching>turf mulching> plastic mulching>retaining wall>control. The soil moisture of retaining wall and control increased gradually from top to bottom and the others showed that middle layer was higher than the layer of top and bottom.3. Effects of different soil moisture conservation on physiological and biochemical indicators of Cupressus chengiana. The photosynthetic rate of Cupressus chengiana had been increased after soil moisture conservation,the increase amplitude was as follows:turf mulching> plastic mulching> weed mulching> retaining wall> control.The water use efficiency of Cupressus chengiana was in the order of control> turf mulching> retaining wall>weed mulching>plastic mulching.The ativity of POD and SOD of control was lower than the soil moisture conservation and the content of MDA of control was the highest.The content of osmotic adjustment substance of soil moisture conservation was lower than control and the chlorophyll's content of soil moisture conservation was higher than control. 4. Effects of different soil moisture conservation on growth increment and biomass of Cupressus chengiana.The annual growth increment of height and diameter of Cupressus chengiana showed a consistent trend after soil moisture conservation,which was in the order of weed mulching>turf mulching>plastic mulching>retaining wall>control. after soil moisture conservation,the survival rate of Cupressus chengiana had reached more than 75%,which was highter than the control obviously.The biomass of each soil moisture conservation was as follows:weed mulching> turf mulching>plastic mulching> retaining wall> control.5. The comprehensive evaluation of each soil moisture conservation. The effect of each soil moisture conservation was analyzed by the method of principal component analysis,the result showed that the effect about the 4 soil moisture conservation was in the order of weed mulching> turf mulching> plastic mulching> retaining wall> control. Because of this,we should prefer the soil moisture conservation such as weed mulching and turf mulching to speed up the vegetation restoration in arid valleys.