摘要
秸秆还田显著影响土壤有机碳激发效应,秸秆不同碳组分对土壤有机碳激发效应影响的方向和强度尚不明确,作用机理仍不清楚。本研究以淮北平原的黄潮土为研究对象,以13C标记的水稻秸秆的水溶性碳、脂溶性碳、残余碳组分和全秸秆碳作为外源碳,利用微宇宙培养方法,研究秸秆不同碳组分添加对土壤有机碳激发效应的影响及作用机理。结果表明,添加秸秆不同碳组分土壤CO_(2)-C排放累积量中,添加水溶性碳处理土壤CO_(2)-C排放速率最高,为29.60 mg·kg^(-1)·d^(-1),而添加脂溶碳、残余碳和秸秆碳之间差异不显著。添加水溶性碳和全秸秆两种外源碳为正激发效应,分别为11.16%和13.39%,而添加脂溶碳和残余碳则表现为负激发效应,分别为-17.04%和-3.06%。相关分析表明,土壤酶活性与秸秆碳组分的TN呈显著正相关(r=0.768**),与C/N呈显著负相关关系(r=-0.776**)。正激发效应与秸秆碳组分的TN和土壤酶活性呈显著正相关关系,负激发效应与秸秆碳组分的TC和TN呈正相关关系,与C/N呈显著负相关。综上,秸秆碳组分与土壤自身有机碳分解的“共代谢理论”是产生正激发效应的主要作用机理,秸秆碳组分C/N的“化学计量比理论”是产生负激发效应的主要作用机理。
Straw return affects significantly priming effect(PE)of soil organic carbon(SOC).However,the direction and magnitude of PE of SOC influenced by carbon components from rice straw are still unclear.The microcosm incubation experiment was carried out to reveal the mechanism of PE in response to different carbon components of rice straw labelled with 13C(hydrated carbon,fat-dissolved carbon,residuetotal and straw)added to fluvo-aquic soil in Huaibei plain.Results showed that the CO_(2) emitted rate was the highest with hydrated C addition across among different carbon components,and reached to 29.60 CO_(2)-C mg·kg^(-1)·d^(-1),while no significant variation across other three carbon components addition.Positive PE were observed in hydrated carbon and total straw addition treatments,which values were 11.16% and 13.39%,respectively.Fat-dissolved carbon and residues addition induced negative PE with-17.04% and-3.06%,The relationship analysis showed that soil enzyme activity was positive to total nitrogen(TN,r=0.768**),and negative to C/N ratio(r=-0.776**).There was positive relationship between PE and TN,enzyme activity,and negative to TC and TN of exogenous carbon component.Above together,the co-metabolism theory of straw carbon and SOC was used to explain the positive PE,and stoichiometry C/N ratio theory could explain the negative PE in the present study.
作者
乔云发
王校益
唐煜杰
苗淑杰
QIAO Yunfa;WANG Xiaoyi;TANG Yujie;MIAO Shujie(School of Ecology and Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing 210044,)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2024年第10期2416-2423,共8页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(42177279,42130506)
江苏省碳达峰碳中和科技创新专项(BE2022312)。
关键词
水稻
秸秆碳组分
激发效应
土壤有机碳
土壤酶
rice
component of rice straw
priming effect
soil organic carbon
soil enzyme
