The Analysis Of Water Requirements Of The Natural Overlapping Vegetation In The Hunshandake Dene

Water is one of the basic natural resources, which is the prerequisite of living and development for biology. While the severe shortage and pollution of water nowadays have become a restraining factor for the health development of ecosystem as well as the sustainable economic development. Hunshandake sand land was a famous water desert in China, but it also exsits serious desertification problem. Therefor, to estimate the accurate water demand of the plants is not only has great significance for the protection and utilization of water resource, but also very important for the ecological construction and increment for farmers and herdsmen.This thesis relies on a project belongs to National Natural Science Foundantion's Analysis of natural Plants Water Demand Calculation and Water Deprivation Study of Hunshandake Sand Land. And it choices Nanshaliang area in Duolun county Xilin Gol, Inner Mongolia as its study area. Nanshaliang locates at the transition zone of farming and stockbreaking area of southern Hunshandake sand land. The study object is the natural overlapping vegetation---arbor grass biocoenosis. This thesis foucus on the water demand of overlapping vegetation, the validity of the results analysis and the relationship between the water demand and its impact factors.This thesis adopts the latest dual crop coefficient menthod introduced by FAO and uses EVAP56 model to confirm the water demand ETo of the study area. It applies SIMDualKc model to calculate different growth stages of overlapping vegetation's crop coefficient Kc. Then to determine the non-growth period crop coefficient. Based on all these calculations, the thesis counts out the water demand Eta of overlapping vegetation in 2006.This thesis also makes an effective entry test of analog result of the water demand and analyzes its diurnal variation. It also studies the relationship between the daily water demand of the overlapping vegetation and other environmental factors as well as vegetation physiological factors.This thesis adopts Isareg model to calculate the water demand of arbor plants in 2006, and finds out that the water content of simulated soil and the actual measurement water content is pretty relevence. By analyzing the simulated result, this thesis thinks it is proper to use Isareg model to simulate the natural vegetation water demand and the result is good. The result also shows that due to the water shortage of that area, the water supply cannot meet the demand during the growth period of the plants, the vegetation production drawdowned seriously.