摘要
为探究酸性水稻土上秸秆还田配施不同用量石灰对温室气体排放的影响机制,本研究采用双因素设计,主区为秸秆用量处理,分别为秸秆不还田(S0)和秸秆还田(S1,5500 kg·hm^(-2))处理,副区为石灰用量处理,分别为不施用石灰(L0)、低石灰用量(L1,3500 kg·hm^(-2))以及高石灰用量(L2,7000 kg·hm^(-2))处理,测定不同处理下温室气体甲烷(CH_(4))和氧化亚氮(N_(2)O)排放及相关微生物丰度与结构、土壤硝化潜势与反硝化能力。结果表明:秸秆还田后CH_(4)累积排放量增加115.5%~144.3%,其作用机制与可溶性有机碳(DOC)的积累密切相关。DOC的积累通过增加产甲烷菌Methanocella属的丰度,抑制了甲烷氧化菌pmoA功能基因的表达,并显著降低了甲烷氧化菌关键属(Methyloparacoccus和Methylomicrobium)的相对丰度,最终加剧了CH_(4)的排放。而石灰施用通过提高土壤pH和硝态氮(NO_(3)^(-)-N)含量,在降低产甲烷菌Methanobacterium属丰度的同时促进了甲烷氧化菌pmoA功能基因的表达,使CH_(4)累积排放量降低21.9%~39.7%。秸秆还田后N_(2)O累积排放量减少了33.0%~38.2%,其减排机制为秸秆还田通过降低narG基因丰度以及关键群落Acidiphilium和Mycolicibacterium属的相对丰度,增加nosZ基因丰度,有效促进N_(2)O向N_(2)还原转化。而石灰处理通过双重调控使N_(2)O累积排放量提高了29.5%~65.0%。具体表现为,铵态氮(NH+4-N)和DOC的降低促进了氨氧化古菌丰度增加,同时pH和N的升高刺激了narG基因丰度的增加和nosZ基因丰度的降低,两者共同增加了硝化和反硝化过程中N_(2)O的产生。秸秆还田增加了全球增温潜势(GWP)和温室气体排放强度(GHGI),而石灰的配合施用有效降低了GWP和GHGI。其中,秸秆还田配施高量石灰能够将GHGI降至0.81 kg·kg^(-1),显著低于L0S0处理。研究表明,对于强酸性稻田土壤,秸秆还田条件下施用高量石灰(7000 kg·hm^(-2))能够有效缓解秸秆还田造成的温室气体排放增加效应,秸秆还田下配施石灰是一种能够实现增产、减排的有效栽培模式。
To explore the mechanisms of greenhouse gas emissions under straw return combined with different lime application rates in acidic paddy soils.This study adopted a two-factor split-plot design.The main plots consisted of straw application treatments:no straw return(S0)and straw return(S1,5500 kg·hm^(-2)).The subplots included lime application treatments:no lime(L0),low lime rate(L1,3500 kg·hm^(-2)),and high lime rate(L2,7000 kg·hm^(-2)).Measurements included greenhouse gas emissions(CH_(4) and N_(2)O),microbial abundance and community structure,soil nitrification potential,and denitrification capacity.The results are as follows:straw return increased CH_(4) emissions by 115.5%-144.3%,and the mechanism of action was closely related to the increase of dissolved organic carbon(DOC).Elevated DOC promoted the abundance of methanogens(Methanocella genus)while reducing the abundance of methane-oxidizing bacteria(pmoA gene)and key genera(Methyloparacoccus and Methylomicrobium).Lime application decreased CH_(4) emissions by 21.9%-39.7%,driven by increased soil pH and NO_(2)^(-)-N content,which enhanced pmoA gene abundance and suppressed methanogens(Methanobacterium genus).Straw return reduced total N_(2)O emissions by 33.0%-38.2%.The abatement mechanism is that the straw return effectively promotes the conversion of N_(2)O to N_(2) reduction by decreasing the abundance of the narG gene and the relative abundance of the key denitrifying genera(Acidiphilium and Mycolicibacterium)and increasing the abundance of the nosZ gene.Lime application increased N_(2)O emissions by 29.5%~65.0%through dual regulatory mechanisms.Specifically,reduced NH+4-N and DOC levels stimulated ammonia-oxidizing archaea(AOA)abundance,while elevated pH and NO_(2)^(-)-N boosted narG gene abundance and suppressed nosZ gene activity,both of which together increased N_(2)O production during nitrification and denitrification.Straw return increased global warming potential(GWP)and greenhouse gas emission intensity(GHGI),while lime application was effective in reducing GWP and GHGI,where high lime application on straw fielding was able to reduce GHGI to 0.81 kg·kg^(-1),which was significantly lower than that of the L0S0 treatment.In conclusion,for strongly acidic paddy soils,combining straw return with high lime application(7000 kg·hm^(-2))effectively mitigates the problem of increased greenhouse gas emission caused by straw-returning.Thus,integrating lime with straw return represents a promising cultivation strategy to achieve greenhouse gas reduction and increase production in rice production systems.
作者
孙梦雨
赵强
吴京
张军
车钊
吴巩
宋贺
李笑笑
SUN Mengyu;ZHAO Qiang;WU Jing;ZHANG Jun;CHE Zhao;WU Gong;SONG He;LI Xiaoxiao(School of Agronomy,Anhui Agricultural University,Hefei 230036,China)
出处
《农业环境科学学报》
北大核心
2026年第1期226-239,共14页
Journal of Agro-Environment Science
基金
安徽省高等学校科学研究项目(自然科学类)重点项目(2023AH050978)
安徽农业大学人才科研资助项目(rc312104)
安徽农业大学2021年校自然科学青年基金项目(K2131001)
安徽省科技攻坚计划重点项目(202423110050045)。
关键词
秸秆还田
石灰
土壤酸化
温室气体
土壤微生物
straw return
lime
soil acidification
greenhouse gas
soil microorganisms
