Study Of Different Water Level Gradient Vegetation Community Biomass Assignment In Mu Us Sandland

Based on a three years monitoring of biomass, air temperature, precipitin, and soil water content at four water level gradient, the above ground and below ground biomass dynamics and its ratio were analyzed. The results showed:1.The dynamics of total biomass various at deferent water level. There was a negative relationship of power-index dropped of root biomass of the water level gradient with the depth of soil profile.2. The vertical distribution of all layers of root and its relation with soil water content had a significantly relations (p<0.05). Changes in soil moisture and root biomass were in inverse ratio. The corresponding regional root biomass decreased when the soil moisture increased. The regression equations as the dependent variables with all levels of soil moisture and the since variables with the root biomass as follow: Y=-245.19X200+282.40 X300+262.373. The seasonal changes of root cap ratio has close relation with the growing season, the root cap ratios' value was larger at the growth pack. There is a negative correlation between the changes in rainfall and the changes to the root cap ratio. The plant will allocate more biomass to shoot when the rainfall increased because of the drought stress was weakened on the vegetation .The establishment of the regression equation is as follows: Y=-0.119J+12.101 J is rainfall.The analysis to the distribution between the ground biomass and underground biomass suggested that the biomass allocation proportion will timely adjust with the degree of drought and the ground growth and underground growth was not equivalent in the MuUs Sandy Land.4. The regression model about the community of ground biomass and ecological factors month by month is established. The research on the ground biomass and environmental factors shows that:(1)The effect were differences of different environmental factors in different stages of plant growth season. The performance was difference in various limiting factors at different growth stages(.2)The importance was differences of the same factors in different stages of plant growth. Soil moisture is important factor in various stages of growing season. According to the analysis of the correlation coefficient, the order of the importance were: 6>7>5>8>9 month(ground);9>6>5>8>7 month(underground).The research on the underground biomass and environmental factors shows that: Rainfall in May has an impact on the accumulation of the underground biomass. The temperature only in August has an impact on the underground biomass. (3)The each mouth biomass was closely related to the last month. It shows that the continuity of plant growth is very important to the accumulation of biomass.