对楸树１～４ａ生幼林进行施肥试验，筛选出人粪尿、尿素、Ｎ＋Ｐ＋Ｋ及饼肥４项较佳施肥组合。通过Ｌｏｇｉｓｔｉｃ模型分析，求出１１项施肥处理对３ａ生树高、胸径速生期起始点、速生点、终止点、速生期长度、速生长速度及速生长量，并证明施肥能改变楸树的速生特性。对叶片、土壤Ｎ，Ｐ，Ｋ及有机质含量进行了动态分析，并作三次抛物线回归模型拟合，证明施肥能提高叶片、土壤中的Ｎ，Ｐ，Ｋ及有机质含量。建立了叶片、土壤两相营养诊断模型２７个，参考模型８个，划出高、低水平营养区及其临界线，建立了楸树幼林的营养诊断模型，提出了诊断时间、诊断标准、诊断方法和合理施肥意见 Fertilization experiments were carried out on the young plantations of Catalpa bungei from 1 to 4 years old, and four combinations of manure urine, urea, N + P + K and cake fertilizer were selected. Through the Logistic model analysis, the results of 11 fertilization treatments on the 3a-tree height, the DBH start point, the fast-growing point, the termination point, the fast growth period, the fast growth rate and the fast growth amount were obtained. characteristic. The leaf, soil N, P, K and organic matter content were analyzed dynamically and fitted by parabolic regression model for three times. It was proved that fertilization could increase N, P, K and organic matter content in leaves and soil. Twenty-seven models of leaf and soil two-phase nutrition diagnosis and eight reference models were set up, and the nutritional thresholds of high and low nutrient areas were set up. The nutritional diagnosis model of Catalpa bungei was established and the diagnosis time, diagnostic criteria, diagnosis Methods and reasonable fertilization advice