桉树营养状况与叶片营养诊断研究

THE NUTRITION STATUS AND FOLIAR NUTRITIONAL DIAGNOSIS OF EUCALYPTUS

本文研究了雷林1号桉、尾叶桉和柠檬桉一年和三年生植株养分浓度及养分积累量；叶片营养诊断的采样时间、诊断方法，并用临界值法和系统综合诊断法（DRIS）诊断桉树施肥“中试”区的营养状况。结果表明：三种桉树的大量养分浓度均以叶最高，全株养分积累量在8月龄时以N、K最高，36月龄时K、Ca较高；营养诊断的最佳采样时间，雷林1号桉和尾叶桉是8月龄，柠檬桉是20月龄；雷林1号桉N、P、K，尾叶桉N、P和柠檬桉P、K临界浓度（g·kg-1）分别为17.2、1.3、4.9、17.0、1．3和1．1、9．6；DRIS诊断参数为K／P、P／N和N／K。

The concentration,absorption of nutrients in 8 months old and 36 months old E.Asizhow 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 nitro gen and potassium at 8 months old and absorbed more potassium and caIcium 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. 1and 9. 6. The diagnosis parameters of DRIS should be K/P,P/N and N/K.