有序样本聚类分析在长序榆苗高生长期划分中的应用

Application of the Sequential Sample Cluster Analysis in the Height Growth Stage Division of Ulmus elongata Seedlings

以长序榆苗高净生长量为样本 ,采用有序样本聚类分析将长序榆苗高生长过程划分为 4个时期 :出苗期为 4月 13日～ 5月 1日 ,生长初期为 5月 2日～ 8月 1日 ,生长盛期为 8月 2日～ 10月 2 1日 ,生长后期为 10月 2 2日～ 12月 1日。生长盛期时间较短 ,但生长量却占总生长量的 74 19% 。

The height growth process of Ulmus elongata seedlings is divided into four stages with the sequential sample cluster analysis,taking the height net growth increment of U.elongata seedlings as samples:emergence stage(Apr.13～May 1),early growth stage(May2～Aug.1),rapid growth stage(Aug.2～Oct.21) and late growth stage (Oct.22～Dec.1).The rapid growth stage is shorter,but its growth increment accounts for 74.19% of the total growth increment.It is very important for the growth increment enhancement to guarantee enough water and fertilizers at the rapid growth stage and lengthen its time.