土壤学报2023，Vol.60Issue(5)：1520-1530,11.DOI:10.11766/trxb202204230204
贝加尔针茅草甸草原土壤有机碳组分对长期氮素添加的响应
Responses of Soil Organic Carbon Components to Long-term Nitrogen Addition in the Stipa baicalensis Meadow Steppe
摘要
Abstract
[Objective]This study aimed to analyze the response of soil carbon composition to long-term nitrogen addition in the Stipa baicalensis meadow steppe.[Method]A nitrogen addition experiment was designed in the meadow steppe of Ewenke Banner,Hulunbuir City,Inner Mongolia in 2010,and 8 nitrogen treatments were set as 0(N0),15(N15),30(N30),50(N50),100(N100),150(N150),200(N200)and 300(N300)kg hm-2·a-1(calculated as N).Soil samples were collected in August 2019 and soil organic carbon and its fractions were measured to investigate the changes and drivers of soil organic carbon and its fractions after 10 years of nitrogen addition.[Results]The results showed that:(1)Compared to the control,soil organic carbon(SOC)content and soil recalcitrant carbon(RP-C)did not change significantly under long-term nitrogen addition.The content of soil labile organic carbon(LP-C)increased,among which labile carbon fraction Ⅰ(LP Ⅰ-C)and Ⅱ(LPⅡ-C)increased by 0.48％-15.59％and 1.94％-8.41％,respectively.Soil easily oxidized organic carbon(EOC)did not respond,whereas the contents of dissolved organic carbon(DOC)and microbial biomass carbon(MBC)changed significantly.The overall soil carbon composition was more sensitive to N addition at the level of 30,50 and 100 kg·hm-2 a-1;(2)The responses of sensitivity index(SI)of soil organic carbon to nitrogen addition showed that MBC was more sensitive to long-term nitrogen addition,which could be used as an indicator suggesting the changes in organic carbon component in the region;(3)Structural equation modeling(SEM)indicated that soil carbon fractions were regulated mainly by plant biomass and soil pH under long-term nitrogen conditions.[Conclusion]Nitrogen addition increases soil labile carbon content in Stipa baicalensis and the changes in soil organic carbon and its fractions are mediated mainly by soil pH and plant biomass.关键词
氮素添加/土壤有机碳/敏感指数/驱动因素/草甸草原Key words
Nitrogen input/Soil organic carbon/Sensitivity index/Driving factors/Meadow grassland分类
农业科技引用本文复制引用
武振丹,马尚飞,卢俊艳,杨殿林,红梅..贝加尔针茅草甸草原土壤有机碳组分对长期氮素添加的响应[J].土壤学报,2023,60(5):1520-1530,11.基金项目
国家自然科学基金项目(31170435)和内蒙古自治区研究生教育创新计划项目(S20210202Z)资助 Supported by the National Natural Science Foundation of China(No.31170435)and the Graduate Education Innovation Program of Inner Mongolia Autonomous Region of China(No.S20210202Z) （31170435）
