不同种植年限人工苜蓿地土壤N2O排放通量  

Soil N_2O flux from artificial alfalfa in different planting years

作　　者：谢应忠 徐坤[1] 

机构地区：[1]宁夏大学西北土地退化与生态恢复国家重点实验室培育基地/宁夏大学西部生态与生物资源开发联合研究中心.银川750021

出　　处：《生态学杂志》2015年第5期1211-1217,共7页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(31160484);国家重点基础研究发展计划前期研究专项(2010CB434805);宁夏高校项目(宁夏绿洲边缘地区农田退耕还草对土壤碳库和土壤碳通量的影响)资助

摘　　要：以半干旱区不同种植年限人工苜蓿地（1、3、4、5和8年）为研究对象，利用静态箱-气相色谱法研究不同种植年限人工苜蓿地土壤系统、土壤-植被系统的N2O排放通量规律，探讨影响土壤N2O排放通量的主要因素。结果表明：（1）苜蓿种植年限影响苜蓿地土壤-植被系统、土壤系统的N2O排放通量，不同种植年限苜蓿地N2O排放通量规律为：4年〉5年〉3年〉8年〉1年。不同种植年限苜蓿地土壤-植被系统、土壤系统的N2O排放通量季节趋势均呈“春夏季高、秋季低”，在5月和8月中旬各出现了N2O排放峰值，表现出N2O的源效应。土壤-植被系统的N2O排放通量大于土壤系统的N2O排放通量。（2）苜蓿地土壤系统N2O排放通量与土壤有机碳、C∶N、铵态氮、全氮、硝态氮含量及0～5 cm土层的土壤温度呈显著正相关，与0～10 cm土壤含水量呈极显著二次负相关。土壤-植被系统N2O排放通量与地上生物量呈极显著正相关。因此，土壤全氮、硝态氮含量、0～10 cm土壤含水量及地上生物量是制约N2O排放通量的关键因子。In order to clarify factors affecting soil N2O fluxes in artificial alfalfa grasslands in the semiarid region of China, the N2O fluxes from soil and soil-vegetation system of artificial alfalfa in different planting years （1, 3, 4, 5, and 8 years old） were measured by using Static box-Gas Chromatography. The results showed that the N2O fluxes from the soil and soil-vegetation system of artificial alfalfa were affected by planting years, and the N2O fluxes of artificial alfalfa were in order of 4 years 〉5 years 〉3 years 〉8 years 〉1 year. The N2O fluxes from the soil and the soil-vegetation system exhibited a seasonal variation of higher in spring and summer and lower in autumn, with highest values in midMay and midAugust, and being a source of N2O. The N2O fluxes from the soil-vegetation system were higher than that from the soil in different planting years. N2O fluxes from the soil had significant positive correlations with the soil organic carbon, total nitrogen, C∶N ratio, ammonium nitrogen, nitrate nitrogen, soil temperature of soil layer （0-5 cm）, and had a significant quadratic negative correlation with soil water content （0-10 cm）. N2O fluxes from the soil-vegetation system had a significant positive relationship with aboveground biomass. Soil total nitrogen, nitrate nitrogen, 0-10 cm soil water content and aboveground biomass were considered as the critical factors controlling N2O fluxes of artificial alfalfa.

关 键 词：种植年限 人工苜蓿 土壤N2O排放 

分 类 号：S541.9[农业科学—作物学]