中山市合果木生长与土壤肥力关系

Correlation between Growth Condition of Paramichelia baillonii and Soil Fertility in Zhongshan City

为探讨合果木在不同土壤情况下的生长表现，选取中山市五桂山、三乡、长江水库及中山树木园4个造林地点对合果木的生长情况进行调查，同时选取土壤质地、土壤容重、pH值、有机质、全氮、全磷、全钾、碱解氮、有效磷和速效钾10个土壤指标作为评价系数，运用修正的内梅罗（Nemoro）综合指数评价法对土壤肥力进行综合评价。结果表明，4个合果木造林地点土壤综合肥力系数P为0．40～0．66，均属于贫瘠土壤；4个造林地点综合肥力系数排序为树木园〉五桂山〉三乡〉长江水库，这与合果木树高和胸径的年生长情况相一致；在土壤贫瘠的情况下，合果木仍能保持较快的生长速度：树高年生长量与土壤综合肥力系数相关性最高．相关系数为0．704，其次为枝下高和胸径年生长量。

In order to understand the growth condition of Paramichelia baillonii under different soils, four sites at Wu- gui Mountain, Sanxiang, Changjiang Reservoir and Zhongshan Arboretum inZhongshan City, Guangdong Province were selected for an investigation of the growth condition of P. Baillonii by using modified Nemoro formula for inte- grated quantitative evaluation of the soil fertility with 10 soil indicators including soil texture, bulk density, pH value, organic matter, total N, P and K, available N, P and K. The results showed that the integrated coefficient p of the four planting sites was between 0. 40 and 0. 66, which meant that the soil was infertile; the integrated coefficient p of the four sites was ordered by Zhongshan Arboretum 〉 Wugui Mountain 〉 Sanxiang 〉 Changjiang Reservoir, which was consistent with the annual growth of height and DBH; P. baillonii still could maintain a rapid growth when the soil was infertile; and the annual height growth and the integrated coefficient pwere best correlated with the correlation coefficient at 0. 704, which was followed by the annual growth of under branch height andthe DBI-I.