峨眉山不同海拔土壤氮素转化动态

摘要

To understand the responses of soil mineral elements dynamics to elevation gradients more comprehensively,soil samples of four typical vegetation distribution zones (775 m,1 575 m,2 433 m, and 3 100 m)in Emei Mountain were collected in July 2013.They’ve cultivate indoor with the method of aerobic incubation for 42 days,and soil NO3—N and NH +4 —N content before and after the incubation were determined and soil net nitrogen mineralization rates were calculated respectively.The results show that the soil temperature,the water content,the total nitrogen content and the total phosphorus content present a trend of regular change along with the altitude gradient.In general,the content of NO3—N and NH +4 —N in the soil increase as the altitudes increase.Soil net nitrogen mineralization rate of different al-titudes is positive,and the N mineralization dominates in the N cycles,which provides a potential nitro-gen pool to alpine plant growing in the non-growing season and the coming spring.The results not only make up for the deficiency of the research on the soil ecological process in Emei Mountain,but also pro-vide a theoretical basis for the study of soil nutrient cycling and vegetation distribution pattern.Further-more,it has great application values in response to global climate change.%为了更全面地了解高山土壤矿质元素动态对海拔的响应，2013年7月采集峨眉山4个典型海拔（775，1575，2433，3010 m）土壤样品，并用好气培养法在室内培养42 d，分别测定培养前后的硝态氮和铵态氮含量，计算土壤净氮矿化率。研究结果表明，峨眉山土壤水温状况、全氮、全磷含量均随海拔梯度改变呈现规律的变化趋势。总体上，随着海拔梯度的升高，土壤中硝态氮和铵态氮含量逐渐增加。峨眉山不同海拔土壤净氮矿化速率均为正值，氮素循环以矿化为主，从而为“非生长季”甚至来年春季高山植物的生长提供了一个巨大的潜在氮库。该研究结果不仅弥补了峨眉山土壤生态过程研究的不足，也为研究峨眉山土壤养分循环和植被分布格局提供了理论基础。