添加玉米秸秆和根茬对不同肥力黑土微生物残体碳氮的影响  

Effects of Maize Shoot and Root Residues Added on Microbial Residue Carbon and Nitrogen in Different Fertility Levels of Black Soil

作　　者：马南 安婷婷[1] 张久明[2] 汪景宽[1] MA Nan;AN TingTing;ZHANG JiuMing;WANG JingKuan(College of Land and Environment,Shenyang Agricultural University/National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources/Key Laboratory of Northeast Arable Land Conservation,Ministry of Agriculture and Rural Affair,Shenyang 110866;Institute of Soil Fertilizer and Environment Resources,Heilongjiang Academy of Agricultural Sciences,Harbin 150086)

机构地区：[1]沈阳农业大学土地与环境学院/土肥高效利用国家工程研究中心/农业农村部东北耕地保育重点实验室,沈阳110866 [2]黑龙江省农业科学院土壤肥料与环境资源研究所,哈尔滨150086

出　　处：《中国农业科学》2023年第4期686-696,共11页Scientia Agricultura Sinica

基　　金：国家自然科学基金面上项目(41977086、42277321);辽宁省科学研究经费项目(LSNQN202008)。

摘　　要：【目的】作物秸秆和根茬是农田土壤有机质的重要来源之一,经微生物作用以微生物残体形式累积在土壤中,是稳定土壤有机质的重要组成部分。明确不同肥力土壤作物秸秆和根茬还田后微生物残体在土壤中的累积及其对土壤有机碳(SOC)和全氮(TN)的贡献,以期为增加土壤碳氮的库容和稳定性提供依据。【方法】基于黑土长期定位试验站不同肥力水平土壤,利用13C15N双标记方法和氨基糖生物标识物技术,土壤中分别添加玉米秸秆和根茬后进行室内培养,在培养第30天和第180天采样,分析土壤中外源碳(秸秆碳和根茬碳)的残留率、外源氮(秸秆氮和根茬氮)的残留率、微生物残体碳氮的含量及其对土壤有机碳(SOC)和土壤全氮(TN)的贡献率。【结果】培养第180天,秸秆碳和根茬碳在土壤中的平均残留率分别为36.3%和31.7%,秸秆氮和根茬氮的残留率平均分别为95.8%和79.3%。添加秸秆和根茬处理SOC中外源碳含量与TN中外源氮含量的比值(13C-SOC/15N-TN)在培养第180天平均分别为17.6和28.5,与培养第30天相比平均分别下降了47.9%和28.2%。培养期间,高肥土壤真菌残体碳氮含量是低肥土壤的1.17倍左右,细菌残体碳氮含量是低肥土壤的1.31倍。第180天,添加秸秆处理土壤微生物残体(真菌和细菌)碳和氮含量平均比添加根茬处理增加了8.5%左右。培养结束后(第180天),真菌残体碳对高肥和低肥土壤SOC的贡献率平均分别为37.0%和33.8%,细菌残体碳的贡献率平均分别为11.2%和9.2%;添加秸秆和根茬的处理真菌残体碳对SOC的贡献率平均分别为36.0%和34.7%,细菌残体碳的贡献率平均分别为10.8%和9.6%。第30天,真菌残体氮和细菌残体氮对TN的贡献率平均分别为55.2%和16.3%;培养第180天,真菌残体氮对低肥和高肥土壤TN的贡献率平均分别为63.5%和60.5%,细菌残体氮的贡献率平均分别为16.4%和17.5%。培养180天与初始土壤相比,【Objective】Maize shoot and root residues are the significance sources of soil organic matter(SOM).Exogenous carbon(C)and nitrogen(N)are assimilated by soil microorganism,accumulated as microbial necromass and contributed to relatively stable SOM.The objectives of this study were to clarify the accumulation of microbial residue C and N in different fertility levels of soil with shoot and root residues addition,and to qualify the contributions of microbial residue C and N to soil organic C(SOC)and total N(TN),respectively,so as to provide a basis for increasing the storage and stability of SOC and TN.【Method】Based on a long-term experiment of black soil with different fertility levels,this study used the13C15N isotope labeling and amino sugar biomarkers methods,and mixed the labeled maize shoot and root residues with black soil samples.Then the mixture samples were incubated in lab,and sampled in 30 and 180 days.The percentages of exogenous C(shoot C and root C)and N(shoot N and root N)remaining in soil,contents of microbial residues C and N,and their contributions to SOC and TN were analyzed.【Result】On the180th day,the percentages of shoot C and root C remaining in soil were,on average,36.3%and 31.7%,respectively,and those of shoot N and root N remaining in soil were,on average,95.8%and 79.3%,respectively.On the 180th day,the ratio of the SOC derived from exogenous C(13C-SOC)to TN derived from exogenous N(15N-TN)were,on average,17.6 and 28.5 in the soils with shoot and root residue addition,respectively.The ratio of13C-SOC to15N-TN was decreased by 47.9%and 28.2%in the soils with shoot and root residue addition on the 180th day compared with the 30th day,respectively.During the incubation,the contents of fungal and bacterial residue in the high fertility soil were,on average,1.17 and 1.31 times those in the low fertility soil,respectively.On the 180th day,the content of microbial residue C and N(fungal and bacterial)was,on average,8.5%higher in the soil added with shoot than that in the soil added with

关 键 词：玉米秸秆 玉米根茬 土壤微生物残体 氨基糖 土壤有机碳 土壤全氮 黑土 

分 类 号：S154.3[农业科学—土壤学]