植物营养与肥料学报2025，Vol.31Issue(4)：621-630,10.DOI:10.11674/zwyf.2024454
长期秸秆还田水稻土团聚体内铁结合态有机碳的分布特征及其性质
Distribution and properties of iron-bound organic carbon of aggregates in paddy soil under long-term straw incorporation
摘要
Abstract
[Objectives]Iron oxides in soil facilitate organic carbon sequestration through adsorption or coprecipitation and serve as critical cementing agents in aggregate formation.This study investigated the effects of carbon input on the content and stability of iron oxide-associated organic carbon within soil aggregates,in order to gain a deeper understanding of the soil organic carbon sequestration mechanism in paddy fields.[Methods]Based on the long-term positioning experiment of double-cropping rice in Qiyang Red Soil Experimental Station in Hunan Province,undisturbed soil samples were collected in treatment plots of the CK(no straw return),RS1(only returning early rice straw to field),and RS2(returning both early and late rice straw to field)continuously for 11 years.The dry-wet sieve method was used to separate soil aggregates into macro-aggregate(>2 mm),small-aggregate(0.25-2 mm),micro-aggregate(0.053-0.25 mm),and clay-silt particle(<0.053 mm).Organic carbon content and iron-bound organic carbon(OCFe)were analyzed across aggregates.OCFe was further partitioned into three fractions:complexed iron-bound organic carbon(OCPP),amorphous iron oxide-bound organic carbon(OCHH),and crystalline iron oxide-bound organic carbon(OCDH).Their proportions in OCFe and aromaticity were quantified.[Results]The proportions of OCPP,OCHH and OCDH in each particle size aggregate were 16.0%-22.4%,1.6%-3.0%,and 0.5%-1.8%,respectively,indicating that the iron-bound organic carbon in the aggregate is mainly OCPP.Compared to CK,RS1 and RS2 increased OCFe content in macro-aggregates by 21.3%and 36.2%,respectively.RS1 significantly enhanced OCFe in micro-aggregates but reduced it in clay-silt particles.Both RS1 and RS2 elevated OCPP in macro-aggregates and OCDH in clay-silt particles,with linear correlations between these two forms of iron-bound organic carbon fractions and aggregate soil organic C(SOC)content,suggesting straw return altered iron-bound organic carbon distribution.Additionally,straw returning increased the aromaticity of OCHH in small-aggregates and OCDH in clay-silt particles.[Conclusions]Straw returning promotes the accumulation of OCPP in macro-aggregates and OCDH in micro-aggregates and clay-silt particles,while enhancing the aromaticity of OCDH in clay-silt fractions.These shifts in iron-bound organic carbon fractions and their stabilization within aggregates likely contribute to increased soil organic carbon sequestration under straw returning,highlighting a key mechanism for SOC preservation in paddy soils.关键词
水稻土/有机碳/团聚体/铁结合态有机碳/芳香性Key words
paddy soil/organic carbon/aggregates/iron-bound organic carbon/aromaticity引用本文复制引用
李冰洁,高菊生,段英华,黄晶..长期秸秆还田水稻土团聚体内铁结合态有机碳的分布特征及其性质[J].植物营养与肥料学报,2025,31(4):621-630,10.基金项目
国家重点研发计划项目(2021YFD1900300) （2021YFD1900300）
中国农业科学院创新工程项目(CAAS-CSAL-202302). （CAAS-CSAL-202302）
