秸秆添加对石灰性土壤有机与无机碳释放的影响  

The Effect of Straw Addition on Organic and Inorganic Carbon Release from Calcareous Soils

作　　者：孙昭安 王方 张珊 张轩 孟凡乔 SUN Zhaoan;WANG Fang;ZHANG Shan;ZHANG Xuan;MENG Fanqiao(Key Laboratory of Biochemistry and Molecular Biology in University of Shandong,College of Biological and Agricultural Engineering,Weifang University,Weifang,Shandong 261061,China;Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation,College of Resources and Environmental Sciences,China Agricultural University,Beijing 100193,China)

机构地区：[1]潍坊学院生物与农业工程学院,山东省高校生物化学与分子生物学重点实验室,山东潍坊261061 [2]中国农业大学资源与环境学院,农田土壤污染防控与修复北京市重点实验室,北京100193

出　　处：《土壤学报》2021年第6期1520-1529,共10页Acta Pedologica Sinica

基　　金：国家重点研发计划项目(2016YFD0201204);山东省自然科学基金项目(ZR2020QD042)资助。

摘　　要：在富含碳酸盐的石灰性土壤上,土壤本身CO_(2)释放不仅来自土壤有机碳(SOC)的分解,也源于无机碳(SIC)的溶解。在秸秆还田下,石灰性土壤CO_(2)释放来源达到三个(秸秆碳、SOC和SIC),由于区分技术的限制,当前区分CO_(2)释放三源的研究,尚少见报道。以华北石灰性农田土壤为研究对象,采用^(13)C标记玉米秸秆添加土壤进行室内培养32周,设置4个处理,分别为无添加对照(CK)、低量秸秆添加(S1,相当于田间秸秆还田量9.6 t·hm^(-2))、中量秸秆添加(S2,秸秆还田量28.8 t·hm^(-2))和高量秸秆添加(S3,秸秆还田量48.0 t·hm^(-2)),利用秸秆碳、SOC与SIC之间的δ^(13)C差异,借助稳定同位素溯源模型IsoSource,区分土壤CO_(2)的释放来源,明确秸秆添加对石灰性土壤有机与无机碳释放的影响。结果表明,随着培养时间的进行,土壤释放CO_(2)中源于秸秆的贡献呈下降趋势;秸秆分解对土壤CO_(2)释放的贡献随着秸秆添加量增加而增加,对于S1、S2和S3处理,土壤释放CO_(2)中源于秸秆、SOC和SIC的贡献比值约分别为3︰3︰4、5︰2︰3和6︰2︰2;与CK相比,S1处理降低SOC分解的激发效应(程度为9%),S2和S3处理反而增加了SOC分解的激发效应(程度分别为22%和57%);秸秆和SOC矿化增加SIC溶解的释放,随秸秆添加量增加而增加,S1、S2和S3处理提高SIC源CO_(2)的释放程度分别为368%、561%和652%。因此,秸秆添加不仅影响SOC源CO_(2)的释放,也增加了SIC源CO_(2)的释放,若忽略SIC溶解对土壤CO_(2)释放的贡献,可能导致SOC矿化量的高估,进而影响SOC激发效应评估的准确度。【Objective】In calcareous soils,recent studies have found that soil-derived CO_(2)not only comes from the decomposition of soil organic carbon(SOC)but also from dissolution of soil inorganic carbon(SIC).Under straw addition,CO_(2)emission in calcareous soils comes from at least three sources,i.e.,straw-C,endogenous SOC and SIC.Owing to technical limitations in source partitioning of CO_(2),the effects of straw addition on SOC and SIC release are still not fully understood in calcareous soils.Therefore,this uncertainty needs urgent attention.【Method】We conducted a 32-week laboratory incubation experiment with^(13)C labeled maize straw under different straw rates in calcareous soils collected from farmlands of North China Plain.The effects of straw addition on CO_(2)emission from SOC decomposition and SIC dissolution were investigated.The approach was based on using three-source mixing model(IsoSource)to differentiate three sources of CO_(2)(straw-C,SOC and SIC).Four treatments were set up,including no straw addition(CK),low rates of straw addition(S1,9.6 t·hm^(-2) of maize straw amendment),medium rates of straw addition(S2,28.8 t·hm^(-2) of maize straw amendment)and high rates of straw addition(S3,48.0 t·hm^(-2) of maize straw amendment).【Result】As the incubation time progressed,the contribution of straw decomposition to soil CO_(2)emission decreased.The contribution of straw decomposition to soil CO_(2)emission increased with the increase of straw addition rates.For S1,S2 and S3 treatments,the soil CO_(2)emission derived from straw,SOC and SIC was about 3:3:4,5:2:3 and 6:2:2,respectively.S1 treatment decreased SOC decomposition by 9%,while S2 and S3 treatments increased SOC decomposition by 22%and 57%,respectively.The mineralization of straw and SOC increased SIC dissolution,and the degree of promotion increased with the amount added.The degrees of promotion for S1,S2 and S3 treatments were 368%,561%and 652%,respectively.【Conclusion】Straw addition not only affected the release of SOC-derived CO_

关 键 词：土壤有机碳 土壤无机碳 秸秆分解 稳定同位素溯源模型 ^(13)C标记 

分 类 号：S147[农业科学—肥料学] S154[农业科学—农业基础科学]