祁连山青海云杉林土壤理化性质和酶活性海拔分布特征

Soil Physicochemical Properties and Enzyme Activities Along the Altitudinal Gradients in Picea Crassifolia of Qilian Mountains

选取祁连山排露沟流域海拔2 900～3 300 m的青海云杉林为研究对象,通过野外采样和室内分析,研究了不同海拔梯度青海云杉林土壤理化性质和酶活性的分布特征,并探讨二者之间的关系。结果表明:(1)随着海拔的升高,土壤含水量、有机质、全氮、速效钾含量逐渐增大;而土壤容重、pH、全钾含量逐渐减小;土壤全磷含量先减小后增大,速效磷含量没有明显的变化规律。(2)随着海拔的升高,土壤蔗糖酶活性和碱性磷酸酶活性总体上呈增强趋势;脲酶活性总体上呈先减弱后增强趋势,蛋白酶活性变化幅度较小且差异不显著(P>0.05)。(3)土壤酶活性和土壤有机质、氮、磷、钾等密切相关,其中蔗糖酶、脲酶、蛋白酶与土壤全氮、全钾、速效钾具有显著相关性(P<0.05)。(4)4种土壤酶活性间呈显著或极显著相关,酶促反应具专一性和共同性特点。

This study selected Picea crassifolia forest which lived at altitudes of 2 900~3 000 m in pailugou catchment of Qilian Mountains as objects.By field investigation and laboratory analysis,the distribution characteristics of soil physicochemical properties and enzyme activities along the altitudinal gradients were studied.The relationships between soil physicochemical properties and soil enzyme activities were also analyzed.The results showed that:(1) With the increased altitudes,soil water contents,as well organic matter,total nitrogen and available potassium contents increased gradually;but soil bulk densities,pH values and total potassium contents decreased gradually;total phosphorus contents decreased at first and then increased,available phosphorus contents had not significant variation.(2) With the increased altitudes,the activities of invertase and alkaline phosphatase showed an increasing trend generally,the activities of urease decreased at first and then increased generally,and the activities of protease changed a little and had no significant difference (P >0.05).(3) Soil enzyme activities were closely related to soil organic matter,nitrogen,phosphorus and potassium contents,among which sucrase,urease and protease activities were significantly correlated with soil total nitrogen,total potassium and available potassium contents (P <0.05).(4) There existed significantly correlations among four enzyme activities,indicating that enzymatic reaction had specificity and commonality.