Biological Cycling of Nutrients in Eucalyptus ABL12W5 Plantation Ecosystem

The accumulation, distribution and biological cycling of nutrients in eucalyptus ABL12W5 plantation ecosystem were studied in Leizhou peninsula, China. Results showed that: the nutrients concentrations were different in various components of eucalyptus ABL12W5, higher content of N, P, K, Ca and Mg being in the leaf, higher one of Ca, K in the bark, and the lowest one of N, P, K, Ca and Mg in the bole; the annual net accumulation of nutrients raised with stand age, and the highest raised degree in the annual net accumulation of nutrients was found in 2 ages stand of eucalyptus ABL12W5; there were also different in the annual absorption and total accumulation of nutrients, N, K or Ca being the highest, following by Mg, P being the lowest; there was obvious raise in absorption and accumulation of Ca in 5 ages of stand of eucalyptus ABL12W5; the returned rates of nutrients of eucalyptus ABL12W5 were very lower, being above 20% for N and Mg, 8% to 14% for Ca, 6.5% to 9% for P, and lower than 5% for K. The eucalyptus plantation ecosystem was in the decline of soil nutrients.