| In April 2005,two investigation sites were selected in Yuanlin Proving Ground of Academy of Agriculture and Forestry Sciences of Ningxia and Tiantan of Zhongning County,respectively.A method with field investigation and chemical analysis in lab was carried out to study the roots distribution of different aged wolfberry and soil nutrients in wolfberry orchard.The wolfberry species was Ningqi No.1,and we chose wolfberry trees with different age to investigate their root distribution,at the same time,soil sample was collected for chemical analysis.The results showed that the average soil nutrients content in wolfberry orchard was greater than cropland in Zhongning,and that of soil available nutrients content was 1.6～2.0 times of cropland.In Yuanlin Proving Ground or Zhongning,the soil organic matter,total N,total P and available nutrients for differently aged wolfberry trees were mainly concentrated in 0～30 cm soil depth. The length of taproots or fibrous roots and tree-crown diameter for wolfberry increased with tree age increasing in Yuanlin Proving Ground.The number of taproots or fibrous roots for 3-year-old wolfberry tree was less than that of 6or 9-year-old tree in Zhongning.The soil depth of root distribution for differently-aged wolfberry tree was mainly ranged from 0 to 35 cm,which was in coincidence with the accumulation depth(0～30 cm) of soil nutrients.That is to say,the farmer's unreasonable fertilization method in wolfberry orchard caused unreasonable distribution of root. |