氮沉降背景下杨树人工林根际和非根际土壤颗粒有机碳和矿物结合态有机碳变化特征OA
Changes of particulate organic carbon and mineral-associated organic carbon in rhizosphere and bulk soil of poplar plantation under nitrogen deposition
[目的]全球氮沉降可能对生态系统功能产生重要影响,研究根际与非根际土壤有机碳(SOC)的差异及其对氮沉降的响应,为进一步揭示未来氮沉降背景下森林SOC循环的响应与适应机制提供理论基础.[方法]以杨树人工林为对象,于2012年5月设置5个氮沉降处理[0、5、10、15、30 g/(m2·a),分别记为N0、N1、N2、N3、N4],当年开始每年进行模拟氮沉降处理.于2023年7月(夏季,生长旺期)、2023年10月(秋季,生长末期)、2024年1月(冬季,非生长期)、2024年4月(春季,生长初期),采集根际和非根际土壤样品,测定土壤颗粒有机碳(POC)、矿物结合态有机碳(MAOC)、SOC含量、酸碱度(pH)、土壤含水率(SWC)、微生物生物量碳、氮(MBC、MBN)、全氮(TN)含量和其他相关的土壤理化性质.基于方差分析、独立样本T检验、相关性分析以及冗余分析等,量化氮沉降处理下根际和非根际土壤POC、MAOC的变化特征,并分析其关键驱动因子.[结果]①氮沉降提高了根际土壤POC含量,与N0处理相比,根际土壤年均POC含量提高6.3％(N1)、19.5％(N2)、20.3％(N3)、28.8％(N4);氮沉降对非根际土壤含量POC没有影响;氮沉降对根际土壤和非根际土壤含量MAOC及其与总有机碳的比例(POC/SOC、MAOC/SOC)均没有显著影响.从季节变化看,根际与非根际土壤的POC含量呈现显著的季节性差异,具体表现为夏季＞秋季＞冬季＞春季;MAOC含量没有显著的季节性差异.②相同氮沉降处理下,根际土壤年均 POC 含量分别比非根际土壤高出 29.5％(N0)、33.1％(N1)、59.9％(N2)、48.8％(N3)、49.7％(N4),根际土壤年均 MAOC 含量分别比非根际土壤高出 41.8％(N0)、52.5％(N1)、32.0％(N2)、59.7％(N3)、48.6％(N4).③冗余分析发现,土壤pH、SOC含量、SWC是驱动非根际土壤POC、MAOC含量变化的关键因子;MBC、pH、MBN、TN含量是驱动根际土壤POC、MAOC含量变化的关键因子.[结论]氮沉降提高了根际土壤POC含量,对非根际土壤POC、MAOC含量和根际土壤MAOC含量均没有显著影响;所有处理下,根际土壤POC和MAOC含量都高于非根际土壤.本研究结果揭示了根际与非根际SOC主要组分的差异及其对氮沉降的不同响应,可为进一步探究SOC对氮沉降响应特征提供理论基础.
[Objective]Global nitrogen deposition may have significant impacts on ecosystem functions.Studying the differences in soil organic carbon(SOC)between rhizosphere and bulk soils and their responses to nitrogen deposition can provide a theoretical basis for further understanding the response and adaptation mechanisms of forest SOC cycling under future nitrogen deposition scenarios.[Method]Taking the poplar plantation as the object,five nitrogen deposition treatments[0,5,10,15,30g/(m2.a),denoted as:N0,N1,N2,N3,N4]were set up in May 2012,and simulated nitrogen deposition treatments were carried out every year starting from that year.Soil samples from the rhizosphere and bulk were collected in July 2023(summer,vigorous growth period),October 2023(autumn,growth end period),January 2024(winter,non-growth period),and April 2024(spring,early growth period).Determine the contents of soil particulate organic carbon(POC),mineral-associated organic carbon(MAOC),SOC,pH,soil moisture content(SWC),microbial biomass carbon and nitrogen(MBC,MBN),total nitrogen(TN),and other related soil physical and chemical properties.Based on analysis of variance,independent sample T-test,correlation analysis and redundancy analysis,etc.,the variation characteristics of POC and MAOC in rhizosphere and bulk soils under nitrogen deposition treatment were quantified,and the key factors driving the changes in their contents were analyzed.[Result](1)Nitrogen deposition increased the POC concentration in rhizosphere soil.Compared with the NO treatment,the annual average POC concentration in rhizosphere soil increased by 6.35％(N1),19.46％(N2),20.28％(N3),and 28.83％(N4).Nitrogen deposition had no effect on the POC concentration in bulk soil.Nitrogen deposition had no significant effect on the MAOC concentration in rhizosphere and bulk soils and the ratios of POC/SOC and MAOC/SOC.Seasonally,the POC concentration in rhizosphere and bulk soils showed significant seasonal differences,specifically summer＞autumn＞winter＞spring;MAOC did not show significant seasonal differences.(2)Under the same nitrogen deposition treatment,the annual average POC concentration in rhizosphere soil was 29.51％(NO),33.06％(N1),59.90％(N2),48.77％(N3),and 49.67％(N4)higher than that in bulk soil,and the annual average MAOC concentration in rhizosphere soil was 41.78％(N0),52.45％(N1),32.05％(N2),59.73％(N3),and 48.63％(N4)higher than that in bulk soil.(3)Redundancy analysis revealed that pH,SOC,and SWC were the key factors driving the changes in POC and MAOC concentration in bulk soil,while MBC,pH,MBN,and TN were the key factors driving the changes in POC and MAOC concentration in rhizosphere soil.[Conclusion]Nitrogen deposition increased the POC concentration in rhizosphere soil,but had no significant effect on the POC and MAOC concentration in bulk soil and the MAOC concentration in rhizosphere soil.Under all nitrogen treatments,the POC and MAOC concentration in rhizosphere soil were higher than those in bulk soil.The results of this study reveal the differences in the main components of rhizosphere and bulk SOC and their different responses to nitrogen deposition,which can provide a theoretical basis for further exploring the response characteristics of SOC to nitrogen deposition.
高雪萍;刘晖晖;施政;方玉;阮宏华;沈彩芹;徐亚明;霍建军;曹国华
南京林业大学生态与环境学院,南方现代林业协同创新中心,江苏 南京 210037南京林业大学生态与环境学院,南方现代林业协同创新中心,江苏 南京 210037南京林业大学生态与环境学院,南方现代林业协同创新中心,江苏 南京 210037南京林业大学生态与环境学院,南方现代林业协同创新中心,江苏 南京 210037南京林业大学生态与环境学院,南方现代林业协同创新中心,江苏 南京 210037江苏省东台林场,江苏 盐城 224243江苏省东台林场,江苏 盐城 224243泗洪县林业科技推广中心,江苏 宿迁 223900江苏省东台林场,江苏 盐城 224243
农业科技
杨树人工林氮沉降根际土壤非根际土壤颗粒有机碳矿物结合态有机碳
poplar plantationnitrogen depositionrhizosphere soilbulk soilparticulate organic carbonmineral-associated organic carbon
《南京林业大学学报（自然科学版）》 2026 (4)
136-145,10
江苏省林业局揭榜挂帅项目(LYKJ[2022]01)国家重点研发计划(2023YFD22004042021YFD2200403)江苏省林业局造林专项项目([2021-2022]).
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