Distribution characters of fine root of poplar plantation and its relation to properties of soil in the northern slope of Qinling Mountain

The vertical distribution characteristic of fine root surface area,fine root volume,root lengthy density,and root biomass of 5-year-old poplar plantation forest,and their relationship with physic-chemical properties of soil in the northern slope of Qinling Mountain were studied.The results indicated that vertical distribution of fine root surface area,fine root volume,root lengthy density and root biomass of poplar forest are with the same trend as all of them decrease with the increase of soil depth.The fine root parameters mostly distributed in the soil layer(0—20 cm),among which about 40% of the fine root parameters distributed in the upper soil layer(0—10 cm),and over 20% of the fine root parameters distributed in the soil layer(10—20 cm).Physic-chemical properties of soil showed different changes of their own(0—80 cm).Soil bulk density among different soil layer decreased with soil depth increase.Soil water content showed small fluctuation with soil depth increase.The pH of soil fluctuated between 6.14 and 6.71 with soil depth increase.Content of organic,total nitrogen and available nitrogen of poplar forest among different soil layer decreased with soil depth increase.The different relevant was existed between the fine root parameters and physic-chemical factors of soil.The results indicated that the vertical distribution of the fine root of poplar forest was influenced by physic-chemical properties of soil,and also reflected the effective strategies of plant of the long-term adaptation to the habitat conditions.