Abstract:

Based on the sampling analysis, concentration and variation of five elements which are N, P, K, Ca and Mg in different organs for three growth stages of Castanea henryi plantation have been studied.The results show retention of each elements gradually become higher from the first stage to the third stage.The accumulation for N and Ca made up large percentage, then was K, Mg, the least was P.During the first growth stage, the return were 1.763 kg·hm ^-2a^-1for N, 1.695 kg·hm^-2a^-1for Ca, 1.252 kg·hm^-2a^-1 for K, 0.632 kg·hm^-2a^-1 for Mg and 0.156 kg· hm^-2a^-1 for P respectively.The second stage, the return increased by 6.6901 kg·hm^-2a^-1 for Ca, 6.0027 kg·hm^-2a^-1 for N, 3.6796 kg·hm^-2a^-1 for K, 2.0822 kg·hm^-2a^-1 for Mg and 0.5945 kg·hm^-2a^-1 for P respectively.But in the third stage, K become the most element of return and the least of return was still P.Circulation rate of each element from the first to the third stages increased and turnover periods shortened.The reasons of variation have also been analyzed.

Key words: Castanea henryi, Nutrient pattern, Biological circulation