Studies On Evapotranspiration Water Consumption Of Tetraploidy Black Locust In Loess Area Of West Shanxi Province

The moisture is an important basis and condition which affects the growth and construction of vegetation. On the loess plaeatu in west of ShanXi province, the evaporation is lager than the pricipatation, so the contradictory of soil moisture supply and demand in forest land is prominent. However,the way of soil moisture consumption includes the transpiration of trees and evapotranspiration of forest land ,so the study on the rule of transpiration and the calculation of evapotranspiration water consumption have the vital significance for contrlling the reasonable stand density and enhancing moisture utilization rate in west of ShanXi province.The paper focuses on the tetraploidy black locust on Loess plaeatu of West Shanxi province, applys steady state promoter method and image processing technology to study the days transpiration water consumption in different weather ,different seasons and different site conditions,has primary analysis on the impact of environment on the transpiration and carries on the calculation to the tetraploidy locust tree by the single leaf water consumption to the single tree water consumption in CaiJiachuan watershed; Uses fast weighing method to measure and analyze the transpiration water consumption of five different herbs under the tetraploidy black locust forest (Capillary Wormwood,Vanilla,Agropyron Sristatum , Common Sowthistle and Medicago Sativa) in short time, in the same and different growcrop,and calculates the average transpiration water consumption per square metres ;the soil colome weighing method was used for determining diumal variation quantity of soil moisture evaporation, analyzing the dynamic variation and caculating the total quantity of soil evaporation water consumption from May to August ; then 5 kind of suppositions about the types of surface vegetation coverage are proposed in experimented site and the total evapotranspiration water consumption are calculated under 5 suppoitions ,aim at providing preliminary theoretic basis for ascertaining the transpiration water consumption of tetraploidy black locust forest,controling standing forest density and optimizing the forest grass deploy on loess plaeatu of west Shanxi province . The main conclusions are as follows:(1) The water consumption of single tetraploid black locust in early stage, middle stage and last stage are 120.8mm, 153.2mm and 191.4mm respectively,and the water consumption in whole gtrowcrop is 465.3mm.(2) The water consumption of Capillary Wormwood, vanilla, agropyron cristatum, Common Sowthistle and medicago sativa under the tetraploid black locust forest are 202.6mm, 299.8mm, 178.3mm, 95.0mm and 79.8mm respectively, and the average water consumption is 1740.4mm.(3) The average soil evaporation water consumption of day and night is 2.7mm,and the total waterconsumption from May to August is 336.8mm.(4) Supposing the research areas are coverd with tetraploidy black locust forest totally with same density (2*2m), the total water consumption in growcrop are 465.3mm.