CONTENTS, ACCUMULATIONS AND BIOCYCLES OF MICRONUTRIENTS IN A CHINESE FIR PLANTATION

This paper was concerned with micronutrients (Fe, Mn, Cu, Zn, B) in a 21-year-old Chinese Fir plantation. Results are as follows: Boron contents is low in soil and leaves (0.5ppm). Element contents in the leaves vary with its ages, but not with its grades of forest growth. Efficiency of using micronutrients is high for Chinese Fir (404.0g/t). The net accumulations of micronutrients are nearly the same in Chinese Fir(2.274 kg/ha.a) and underplants (2.145kg/ha.a). The micronutrient biocycle rate is 66.5 percent, the uptake is 5.445kg/ha.a, the retention and restitution are 1.823kg/ha.a, and 3.622 kg/ha.a respectively. According to the use of whole tree, the biomass removal increases by 53.9 percent, and the micronutrient loss 171.9 percent.