杉木大径材培育施肥配方选择研究

在树龄14年生、18年生和21年生时，3次对同一片杉木林分进行固定7种处理（含对照） 的施肥试验，30年生时进行标准地每木调查，研究结果表明不同配方施肥处理的杉木平均树高、胸径及大径材株数比例相比对照（不施肥）增益分别为0.4％ ～3.5％、3.6％ ～10.0％和3.3％ ～11.7％。单位面积总蓄积量、大径材蓄积量增益分别为3.0％ ～21.0％、5.2％ ～46.9％。以每株施150ｇＮ＋300ｇＰ205＋100ｇk20的增产效果最佳，大径材株数比例达55.0％，出材率提高２24.3％;以每株施100ｇＮ＋300gp205+100gk20的经济效益最高，投入产出比12.93。

A fertilization trial involving 7 fixed treatments (including a control) was performed three times on the same Chinese fir stand when the trees were 14, 18, and 21 years old. An individual-tree survey on standard sample plots was conducted when the stand attained 30 years of age. The results demonstrated that relative to the unfertilized control, the various formulated fertilization treatments yielded gains of 0.4%–3.5%, 3.6%–10.0%, and 3.3%–11.7% in average tree height, diameter at breast height (DBH), and proportion of large-diameter timber stems, respectively. The gains in total standing volume per unit area and large-diameter timber standing volume were 3.0%–21.0% and 5.2%–46.9%, respectively. The treatment applying 150 g N + 300 g P₂O₅ + 100 g K₂O per tree achieved the best growth-promoting effect, with the proportion of large-diameter timber stems reaching 55.0% and the timber yield rate increased by 24.3% (the redundant full-width character "2" in the original text is presumed to be a typo). The treatment applying 100 g N + 300 g P₂O₅ + 100 g K₂O per tree delivered the highest economic benefit, with an input-output ratio of 12.93.