浙闽毛竹林土壤有效硅地理分布规律

GEOGRAPHIC DISTRIBUTION LAW OF AVAILABLE SILICON IN SOILS IN THE STANDS OF PH. PUBESCENS IN ZHEJIANG AND FUJIAN PROVINCES

通过对浙江，福建的主要毛竹产区的林下土壤，对１７２个剖面采用典型调查的方法，采集各类土样８３３个进行有效硅含量的测试，初步阐述了该区毛竹林土壤有效硅的含量状况、地理分布特征；说明土壤有效硅具有从南到北逐渐递增的纬度地带性规律和随海拔从低到高，土壤有效硅含量逐渐增多甚至骤增的垂直地带性规律。在三大类岩石中，一般火成岩（本调查中花岗岩类和高海拔区凝灰岩除外）发育的土壤有效硅含量较低，沉积岩则高，变质岩则由于其来源和变质作用的复杂性而使其发育土壤的有效硅状况呈现不规律性。在各土壤类型中，其有效硅含量顺序为：山地黄壤＞石灰性土）山地黄棕壤＞山地红壤≥黄红壤＞酸性紫色土≥低丘红壤。对特征剖面研究发现，客土和劈山等毛竹林栽培措施对有效硅在土壤剖面分布有较大的影响。本研究结果绘制的该区有效硅低值含量分布图，可以为纸浆竹林基地的选择提供初步的建议。

By the method of typical investigation on 172 profiles of the soil in majorPh.pubesccns forests in Zhejiang and Fujian Prov,633 samples of soil were tesed to an-alyse the available Si content.The result showed the condition of the soil available Si con-tent and its geographic region. It is indicated that the distribution of the soil available Sihas a latitudinal zonalitv trend of increase from the south to north and a vertical zonalitytrend of increase from low to high altitude. Among the 3 kinds of rock, the soil availableSi content was quite low in general igneous rock except for granite and tuff at higher eleva-tion in this investigation. It, however，was comparatively high in sedimentary rock．Butin metamorphic rock no significant trend appears.The of the available Si content insoil was as the following:mountain yellow earch＞calcareous soil＞mountainyellow-brown earth＞mountain red earth＞yellow-red earth＞acid purple soil＞low hillred earth．Researching the typical profile,we found that the measures such as borrowingsoil，cleaving grass etc. had great effect on the character of Si profile distributionin Ph.pubescens stands.A distribution map of low available Si content was made so as toprovide the information for the selection of the paper-pulp bamboo forest base.