杉木人工林根际土壤性质变化的研究

本文重点论述一代杉木人工林根际和非根际土壤生物活性、生物化学活性、土壤化学性质的差异及其在林木生长过程中的动态变化规律。研究结果表明：杉木幼龄林、中龄林及近熟林样地土壤中有机养分和无机养分含量，除去幼龄林土壤中全Ｋ 之外，均是根际土壤养分含量高于非根际土壤。不同发育阶段养分变化规律：速效Ｎ 在根际和非根际均呈下降趋势；速效Ｐ 含量也呈下降趋势，仅从中龄林至近熟林略有恢复，但全Ｐ含量一直呈下降趋势，速效Ｋ 由幼龄林至中龄林呈升高趋势，但由中龄林至近熟林呈下降趋势，全Ｋ 只是从中龄林至近熟林呈下降趋势。Ｃｕ、Ｚｎ 、Ｍｎ 含量，从幼龄林至中龄林呈大幅度下降，中龄林至近熟林在非根际土壤中略有恢复。关于土壤酶活性变化，无论是水解酶类、还是氧化还原酶类活性，在杉木幼龄林时期，均是根际土壤酶活性低于非根际土壤，随着林木生长至近熟林，则逐渐出现根际土壤酶活性高于非根际土壤。土壤微生物区系研究结果表明：在幼龄林阶段根际土壤细菌、放线菌和真菌均多于非根际土壤，从幼龄林至中龄林根际土壤和非根际土壤细菌和真菌均呈下降趋势，但放线菌数量在增多，由中龄林至近熟林，细菌、真菌和放线菌在根际和非根际土壤中数量趋于提高。在杉木生长过程中，根际和非

RESEARCH ON CHANGE OF RHIZOSPHERE SOIL PROPERTIES OF CHINESE FIR PLANTATION

This article emphatically reviews the difference of soil biological activities,biochemical activities and soil chemical propeties between the rhizosphere and non rhizosphere soil of first rotation of Chinese fir( Cunninghamia lanceolata (Lamb)Hook)plantation. It also reviews their dynamic patterns during Chinese fir plantation development. The results show that the contents of organic and inorganic nutrients in the rhizosphere soil of young,half mature and near mature Chinese fir of first rotation are more than those in non rhizosphere soil,except for total K in young Chinese fir plantation. Various patterns of soil nutrients in different stages of Chinese fir plantation development are as follows:Available N shows the trend of declination in both rhizosphere soil and non rhizosphere soil;the content of available P also declines,only increases a little from half mature stage to near mature stage,but total P decreases from beginning to end.The content of available K increases from young stage to half mature stage,but decline from half mature stage to near mature stage both available K and total K.The contents of Cu,Zn,Mn,decrease greatly from young stage to half mature stage,and rehabilitate a little from half mature stage to near mature stage in non rhizosphere soil. As for the variation of the soil enzyme activity,both hydrolytic enzyme and oxidizing enzyme are less active in rhizosphere soil than in non rhizosphere soil at young stage.However,when Chinese fir become into mature,the activities of soil enzymes are higher in rhizosphere soil than those in non rhizosphere soil.The results of soil micro flora show that the quantity of bacteria,actinomyces,fungi in rhizosphere soil is more than that in nonrhizosphere soil in the young Chinese fir plantation.The quantity of bacteria and fungi decreases in rhizosphere and non rhizosphere soil,but the quantity of actinomyces increases along with the Chinese fir becoming into half mature.From half mature Chinese fir plantation to near mature stage,the quantities of bacteria,actinomycetes and fungi increases.The variation of the three types of microorganism in genus,species and amount in rhizosphere soil and non rhizosphere soil during stages of Chinese fir plantation development indicates the dynamic process of soil degradation.The clear scientific evidences are provided for revealing mechanism of soil degradation of Chinese fir plantation and finding technigue way of prevention and cure by researching soil properties of rhizosphere and non rhizosphere.