Soil Priming Effect Mediated by Nitrogen Fertilization Gradients in a Semi-arid Grassland, China  

中国半干旱草原施氮梯度下的土壤激发效应（英文）

作　　者：LI Yue NIE Cheng SHAO Rui DU Wei LIU Yinghui 李悦;聂成;邵蕊;杜薇;刘颖慧(北京师范大学地理科学学部地表过程与资源生态国家重点实验室,北京100875;比利时根特大学地理系)

机构地区：[1]State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875,China [2]Department of Geography, Ghent University, Ghent 9000, Belgium

出　　处：《Journal of Resources and Ecology》2019年第2期147-154,共8页资源与生态学报（英文版）

基　　金：National Natural Science Foundation of China(31770519);National Key Research and Development Program of China(2017YFC0503805)

摘　　要：The priming effect is well acknowledged in soil systems but the effect of nitrogen(N)fertilization remains elusive.To explore how N modifies the priming effect in soil organic matter(SOM),one in situ experiment with 13C labeled glucose addition(0.4 mg C g^–1 soil,3.4 atom %^13C)was conducted on soil plots fertilized with three gradients of urea(0,4 and 16 g N m^–2 yr^–1).After glucose addition,the soil CO2 concentration and phospholipid fatty acid(PLFA)were measured on day 3,7,21 and 35.The study found that N fertilization decreased soil CO2,PLFA and the fungi to bacteria ratio.Glucose triggered the strongest positive priming in soil at 0 g N m^–2 yr^–2,meanwhile N fertilization decreased SOM-derived CO2.Soil at 4 g N m^–2 yr^–2 released the largest amount of glucose-derived carbon(C),likely due to favorable nutrient stoichiometry between C and N.Stable microbial community biomass and composition during early sampling suggests"apparent priming"in this grassland.This study concludes that N fertilization inhibited soil priming in semi-arid grassland,and shifted microbial utilization of C substrate from SOM to added labile C.Diverse microbial functions might be playing a crucial role in soil priming and requires attention in future N fertilization studies.为了探究施氮对土壤有机质(SOM)的激发效应,本研究在施氮梯度样地(0、4和16 g N m^(–2) yr^(–1))上进行了^(13)C标记葡萄糖的原位添加实验,并对土壤CO_2排放量和磷脂脂肪酸(PLFA)含量进行了测定。研究发现施氮降低了土壤CO_2排放、土壤PLFA含量以及土壤真菌细菌比。在0 g N m^(–2) yr^(–1)样地上葡萄糖添加导致的正向激发效应最强,同时4 g N m^(–2) yr^(–1)样地释放的葡萄糖来源的碳最多。因此,施氮减少了土壤中SOM转化产生的CO_2,微生物碳的来源由SOM转变为添加的易分解碳。本研究采样早期土壤微生物生物量和群落结构稳定,表明该草原存在"表观激发效应",因此未来研究应着重对微生物功能的多样性进行探讨。

关 键 词：nitrogen fertilization ^13C labeled glucose soil priming effect phospholipid fatty acids semi-arid grassland 

分 类 号：S812.2[农业科学—草业科学]