Study on Underground Biomass of Tamarix ramosissima in the Middle Reaches of Tarim River

The underground biomass status,vertical distribution and its relationship with aboveground biomass of Tamarix ramosissima in middle reaches of Tarim River was studied.The results showed that: the biomass of Tamarix ramosissima was 28.06 kg / m2,among which 19.7% was aboveground biomass(5.53 kg / m2) and 80.3% was underground biomass(22.53 kg/m2).Underground biomass decreased with soil depth,and the maximum of underground biomass was found in 0-40 cm(38.7%).The regression equation of underground and aboveground biomass is y =-0.249x2 + 6.624x-1.356,R2 = 0.674.It was clear that aboveground biomass could explain 67.4% underground biomass variation.When referring to research at different spatial scales in different zones,we needed a large number of actual biomass data to fit equation again.