模拟氮沉降下喀斯特原生乔木林土壤养分的动态分析

A Dynamic Analysis of the Soil Nutrients of Karst Primary Arbor Forest under Simulated Nitrogen Deposition

为了探究氮沉降背景下喀斯特森林生态系统土壤养分的响应特征。本文研究了贵州喀斯特原生乔木林土面和石沟小生境在模拟不同氮沉降水平下土壤养分的动态变化。结果表明:随着施氮水平的增加,NH4+-N、NO3--N、有机碳、有效钾含量上升,pH值、全磷含量出现不同程度的下降,有效磷、全钾含量随施氮水平不同而变化趋势不同。不同小生境各土壤养分含量对氮沉降的响应石沟略高于土面,但受小生境影响不显著,可能是氮沉降强度和沉降时间还不足以引起土壤养分的显著变化,也说明了喀斯特森林生态系统对氮沉降有一定的缓冲性。

In order to explore the responding characteristics of soil nutrients under different nitrogen deposition in Karst forest ecosystem,in this paper,the dynamic changes of soil nutrients in niches of soil surface and stony gully of karst primary arbor forest under simulated different nitrogen deposition were studied.The results showed that the content of NH4+-N,NO3--N,organic carbon and available potassium increased with the increase of nitrogen application,and the pH value and total phosphorus content decreased by different degrees.The content of available phosphorus and total potassium changed with different trend under different nitrogen application.The response of soil nutrient contents of stone gully to N deposition was slightly higher than that of soil surface,but it was not significantly affected by the niches.It may be that N deposition intensity and time were not enough to cause significant changes of soil nutrient,which also indicated that the Karst forest ecosystem had certain buffering effect on N deposition.