晋北农牧交错带草地土壤总硝化速率对放牧强度的响应  

Response of Total Nitrification Rate to Grazing Intensity in TheAgro-Pastoral Ecotone in Northern Shanxi

作　　者：郝杰 刁华杰 武帅楷 苏原 高阳阳 梁雯君 牛慧敏 杨倩雯 常婕 马腾飞 王亭帅 齐志远 王常慧[2,3,4] 董宽虎 HAO Jie;DIAO Hua-jie;WU Shuai-kai;SU Yuan;GAO Yang-yang;LIANG Wen-jun;NIU Hui-min;YANG Qian-wen;CHANG Jie;MA Teng-fei;WANG Ting-shuai;QI Zhi-yuan;WANG Chang-hui;DONG Kuan-hu(College of Forestry,Shanxi Agricultural University,Taigu,Shanxi Province 030801,China;College of Grassland Science,Shanxi Agricultural University,Taigu,Shanxi Province 030801,China;Shanxi Key Laboratory of Grassland Ecological Protection and Native Grass Germplasm Innovation,Taigu,Shanxi Province 030801,China;Youyu Loess Plateau Grassland Ecosystem Research Station,Youyu,Shanxi Province 037200,China)

机构地区：[1]山西农业大学林学院,山西太谷030801 [2]山西农业大学草业学院,山西太谷030801 [3]草地生态保护与乡土草种质创新山西省重点实验室,山西太谷030801 [4]山西右玉黄土高原草地生态系统国家定位观测研究站,山西右玉037200

出　　处：《草地学报》2024年第9期2769-2776,共8页Acta Agrestia Sinica

基　　金：国家自然科学基金区域创新发展联合基金重点项目(U22A20576,32301375);山西省重点实验室项目(202104010910017)资助。

摘　　要：为探究不同放牧强度对北方农牧交错带草地功能微生物参与的硝化过程影响机理。本研究以设置不放牧(0羊单位·hm^(-2)·生长季^(-1))、轻度(2.35羊单位·hm^(-2)·生长季^(-1))、中度(4.80羊单位·hm^(-2)·生长季^(-1))和重度(7.85羊单位·hm^(-2)·生长季^(-1))4个放牧强度的放牧实验平台为研究对象,通过同位素^(15)N库稀释法,测定土壤总硝化速率。结果表明:相比于对照,土壤总硝化速率在轻度、中度和重度放牧处理下分别提高了18.1%,6.2%,22.1%;氨氧化细菌基因AOB amoA丰度分别提高了10.72%,8.92%,42.01%,但在不同放牧强度之间无显著差异。土壤总硝化速率(6.72 mg·kg^(-1)·d^(-1))及AOB amoA拷贝数(1.12×10^(7)copies·g^(-1))最高值均出现在9月份,且整体高于其他月份。本研究表明,氨氧化细菌是参与晋北农牧交错带放牧草地土壤总硝化速率的主要微生物。此外,土壤含水量、铵态氮含量及土壤微生物生物量氮是影响土壤总硝化速率的关键因子。To explore the mechanism of the effect of different grazing intensities on the nitrification process involving functional microorganisms in grasslands of the northern agro-pastoral ecotone.This study focused on a grazing experimental platform with four grazing intensities:no grazing(0 sheep units·hm^(-2)·growing season^(-1)),light grazing(2.35 sheep units·hm^(-2)·growing season^(-1)),moderate grazing(4.80 sheep units·hm^(-2)·growing season^(-1)),and heavy grazing(7.85 sheep units·hm^(-2)·growing season^(-1)).The soil total nitrification rate was measured using the isotope^(15)N pool dilution method.The results showed that compared to the control,the soil total nitrification rate under light,moderate,and heavy grazing treatments increased by 18.1%,6.2%,and 22.1%,respectively.The abundance of ammonia-oxidizing bacteria gene AOB amoA increased by 10.72%,8.92%,and 42.01%,respectively,but there were no significant differences among different grazing intensities.The highest values of soil total nitrification rate(6.72 mg·kg^(-1)·d^(-1))and AOB amoA copy number(1.12×10^(7)copies·g^(-1))were both observed in September and were generally higher than in other months.This study indicates that ammonia-oxidizing bacteria are the main microorganisms involved in the soil total nitrification rate in grazing grasslands of the northern agro-pastoral ecotone.Additionally,soil moisture content,ammonium nitrogen content,and soil microbial biomass nitrogen are the key factors affecting the soil total nitrification rate.

关 键 词：总硝化作用 放牧强度 农牧交错带 氨氧化古菌 氨氧化细菌 

分 类 号：S812.2[农业科学—草业科学]