秦岭山脉典型林分土壤酶活性与土壤养分关系的探讨

摘要

秦岭作为我国南北方气候的分界线，其上生长着许多独特林分，加之未受到人为活动扰动，故对其包括土壤酶及养分等在内的土壤效应研究具有重要参比性，且可为揭示不同林分的土壤效应及筛选最优林分奠定基础。选取秦岭不同海拔生长的五种典型林分（锐齿栎、油松、华山松、云杉及松栎混交）土壤，分析了7种土壤酶活性和养分变化特征，并探讨了二者间关系及林分的影响。结果表明：不同林分下土壤养分及酶活性变化差异较大，土壤性质强烈受到林分种类及海拔等生态环境条件的影响，其中云杉土壤的有机质、全氮、碱解氮、速效钾、缓效钾含量均较高，是秦岭山脉生长较好的树种之一；且土壤有机质、全氮、碱解氮等养分变化规律较一致；土壤碱性磷酸酶、荧光素二乙酸酯（FDA）水解酶及总体酶活性（TEI）与土壤养分呈显著或极显著正相关，表明林分和海拔对这三种酶的影响与养分是一致的；采用单独土壤酶活性与土壤酶和化学性质复合开展的主成分分析结果一致，获得的综合得分与上述三种酶类达显著或极显著正相关，揭示出它们在一定程度上可表征森林土壤的质量水平，且单一酶类中土壤碱性磷酸酶活性可更容易、简便地反映土壤肥力状况的变化。%[Objective]As the Qinling Mountain is the division line between the two climate zones, south and north in China,the mountain,as a result of its huge variation in climate and altitude,has a great number of unique forest stands that have never been disturbed by human activities. Therefore,the study on the soils under these forests,including soil enzymes and nutrients,can be of great reference value to the studies on other types of soils,and may lay down a foundation for revelation of soil effects relative to forest stand and selection of optimal forest stands. [Method]In this study,soils samples were collected from five typical types of forest stands(Quercus aliena var. acuteserrata,Pinus tabuliformis,Pinus armandii, Picea asperata,and pine-oak mixture)at various altitudes,for analysis of activities of seven soil enzymes and soil nutrients,so as further to determine relationships between the two as affected by type of the forest stand. [Result]Results show that significant differences in soil enzyme activity and soil nutrient existed between the forest stands. Properties of the soils were significantly affected by type of forest and bio-environment conditions,such as attitude. The soil under Picea asperata(one of the dominant well-grown species in the Qinling Mountain)was the highest in organic matter,total N,alkalytic N,readily available potassium and slowly available potassium,and what is more,soil organic matter,total N and alkalytic N followed similar trends;soil alkaline phosphatase,fluorescein diacetate(FDA)hydrolase and the total enzyme activity index(TEI)were in significantly positive or extremely significant and positive relationships with soil nutrient,which indicates that forest and altitude have similar influences on the three types of enzymes like soil nutrient does. Principal component analyses(PCA)of sole soil enzyme activity and combination of soil chemical properties and soil enzyme activity were quite similar in result,with integrated scores significantly and positively related to the above-listed three enzymes. [Conclusion]So soil alkaline phosphatase,FDA hydrolase and TEI can be used as indicators of quality of forest soils,especially soil alkaline phosphatase that can be easily used as a single enzyme indicator to reflect soil nutrient condition. Other than those,no soil enzymes are found so closely related to soil chemical properties.