Abstract:

The concentration, absorption of nutrients in 8 months old and 36 months old E. Leizhow No. 1, E. urophylla and E. citriodora were studied. The sampling time of leaves for nutritional diagnosis and the methods of nutritional diagnosis were discussed. The nutrition status of Eucalyptus in medium-expand experiment plots of Eucalyptus fertilizing were diagnosed by using diagnosis of eritical concentration and diagnosis and recommendation of integrated system (DRIS).The results indicated that the value of macro-nutrients concentration in leaves was the highest for all three Eucalyptus, that the Eucalyptus would absorped more nitrogen and potassium at 8 months old and absorbed more potassium and calcium at 36 months old. It was showed that the optimal time of leaf sampling in nutribnt diagnosis was at 8 months old for E. leizhow No. 1 and E. urophylla at 20 months old for E. citriodora. The critical concertration (g·kg^-1 of N, P and K for E. Leizhow No. 1 was 17.2, 1.3 and 4.9 respectively, and that of N, P for E. urophylla was 17.0 and 1.3, and P, K for E. citriodora was 1.1 and 9.6. The diagnosis parameters of DRIS should be K/P, P/N and N/K.

Key words: Eucalyptus, Nutrition status, Fertilization, Nutritional diagnosis, Critical concentration, DRIS