YU YUAN-CHUN;ZHANG HUAN-CHAO

;Nanjing Forestry University, Nanjing 210037 (China)

broad-leaf tree;chinese fir;mixed stand;soil nutrient status

The effects of different types of Chinese fir stand, including those with various composition (pure and mixed), in various cropping systems (first and continuous cropping system) and at different ages, on the nutrient status of soils in the hilly regions of southern Anhui Province were studied by means of ecological sequential comparison on the basis of similar climate and soil type. The work was carried out in the Xiaoxi Forest Farm of Jingxian County and the Caijiaqiao Forest Farm of Jingde County,where the soil is parayellow soil derived from phyllite and sandstone. The results revealed that with the increase of age, Chinese fir pure stand could accumulate organic matter and nitrogen in the soil but it resulted in decreasing of soil pH and baseions (especially Ca~(2+)) compared to its mixed stand with broad-leaf trees such as Chinese sassafras. In order to improve the soil fertility, it would be better to mix Chinese fir with broad-leaf trees when afforestation. In the management of Chinese fir pure stand, base compounds and phosphates should be added to the soil for maintaining soil fertility and raising forest productivity.