FINE ROOTS DISTRIBUTION PATTER OF POPULUS DELTOITES PLANTATIONS IN YELLOW RIVER FLUVIAL PLAIN

By using method method of modified whole root research,the study was conducted to discuss the spatial distribution of root system of 3a,6a,9a the three stand age of P.deltoites cv.Zhonghe-1'in the Yellow River alluvial plain,and analyze root biomass,root length,length density,surface area and volume of fine root≤2 mm in diameter.Results showed that,in vertical direction,the root biomass,root length,length density,surface area and volume of roots≤2 mm in diameter in every stand age of poplar plantation in general is gradually increased with soil depth decreases,and there are a significant differences between different stand age and different soil layer.Fine roots are distributed evenly in the horizontal,but between stand age and between different distances from the trunk still showed obvious difference.The space distribution of fine roots in Poplar plantation provides the basis for woodland soil improvement and fertilizer.