IMPACT OF FERTILIZATION ON CURRENT ANNUAL INCREMENT(CAI) OF YOUNG CHINESE FIR AND MAIN INFLUENCE FACTORS IN DIFFERENT AREAS

A preliminary study on the impact of fertilization on CAI of young Chinese fir in different areas showed: In Xinyang, Henan Province, the effect of N fertilizer of P fertilizer was better in the first year of fertilization, but the effect of mixed fertilization of NP, KP or NPK was better than that of treatments of only N or P. The optimum one was treatment 11(NP2K1,which leads to an increase of the CAI of tree height and diameter in the breast height by 39%～104% and 54%～136% compared to the control(CK),respectively . In Fenyi, Jiangxi Province, the effect of fertilization on diameter at the breast height was bigger than that on the tree height; the effect of P fertilizer was good whether it was applied mixed with other fertilizers or not. Among all the P treatments the effect of treatment 3(P3) was the most significant one, the CAI of diameter at the breast height of young Chinese fir was increased by 13%～37% within the four year of fertilization experiment. In Shunchang, Fujian Province, the effects of fertilization for young Chinese fir on the tree height and diameter were not so significant like that of the two areas mentioned above, further, this effect was not stable; the effect of fertilization in the third year was bigger that in other years, the treatment 9(P1K1) was the best one. The important factors influencing the impact of fertilization on CAI of young Chinese fir are soil fertility, soil depth, climate and the beginning condition of the nursery stock such as the height and ground?diameter.