李彬彬,馬軍花,武蘭芳
(1. 生態(tài)系統(tǒng)網(wǎng)絡(luò)觀測與模擬重點(diǎn)實(shí)驗(yàn)室,中國科學(xué)院地理科學(xué)與資源研究所, 北京 100101; 2. 青島農(nóng)業(yè)大學(xué), 青島 266105)
土壤溶解性有機(jī)物對CO2和N2O排放的影響
李彬彬1,2,馬軍花1,*,武蘭芳1
(1. 生態(tài)系統(tǒng)網(wǎng)絡(luò)觀測與模擬重點(diǎn)實(shí)驗(yàn)室,中國科學(xué)院地理科學(xué)與資源研究所, 北京 100101; 2. 青島農(nóng)業(yè)大學(xué), 青島 266105)
農(nóng)田土壤是溫室氣體的重要排放源,溶解性有機(jī)物作為土壤微生物容易利用的基質(zhì),其含量變化與溫室氣體的產(chǎn)生和排放密切相關(guān)?;谑覂?nèi)培養(yǎng)試驗(yàn),對溶解性有機(jī)物影響土壤CO2、N2O的排放過程進(jìn)行了分析。設(shè)置空白(CK)、單施秸稈(S)、單施氮肥(N)、秸稈和氮肥(S+N)4個不同的處理,對添加不同物質(zhì)條件下土壤溶解性有機(jī)碳(DOC)、溶解性有機(jī)氮(DON)和CO2、N2O的排放動態(tài)進(jìn)行了研究,對DOC和DON影響CO2、N2O的排放過程進(jìn)行了探討。結(jié)果表明:不同處理的溫室氣體排放通量和土壤DOC、DON含量差異顯著;各處理的CO2排放通量和DOC動態(tài)隨培養(yǎng)時間的延長呈現(xiàn)逐漸減小的趨勢,S和S+N處理的N2O排放和DON動態(tài)呈現(xiàn)先增大后減小的趨勢; S+N處理的CO2排放量最高,DON含量也顯著高于其他處理,單施秸稈(S)處理的N2O排放量和DOC含量顯著高于其它處理,單施氮肥(N)對土壤CO2的排放量和DOC含量的影響較??;土壤CO2和N2O的排放通量與土壤DOC和DON含量呈顯著的相關(guān)性,相關(guān)系數(shù)(R2)達(dá)0.6以上,說明溶解性有機(jī)物的含量和動態(tài)對CO2、N2O的排放過程產(chǎn)生顯著影響。
溶解性有機(jī)碳;溶解性有機(jī)氮;溫室氣體;秸稈;氮肥
近年來,溫室氣體的排放所引起的全球氣候變暖是科學(xué)家們廣泛關(guān)注的問題。在北方旱地土壤中,溫室氣體主要是指CO2和N2O,據(jù)估計,5%—20%的CO2和80%—90%的N2O來源于土壤[1]。土壤是溫室氣體產(chǎn)生的重要來源,其碳氮含量的改變與CO2和N2O排放密切相關(guān)。溶解性有機(jī)物(DOM)是表征土壤有機(jī)質(zhì)快速變化的最敏感指標(biāo)之一,其含量變化對研究土壤養(yǎng)分循環(huán)和溫室氣體的排放具有重要作用[2]。溶解性有機(jī)碳(DOC)和溶解性有機(jī)氮(DON)是DOM的主要組分。
土壤DOC、DON含量和動態(tài)對CO2、N2O排放過程產(chǎn)生重要影響。在沼澤土壤中,DOC含量與CO2排放有一定的相關(guān)性[3];Chow在研究影響農(nóng)業(yè)泥炭土壤DOC產(chǎn)生和碳循環(huán)過程的因素中指出CO2礦化量和DOC濃度密切相關(guān)[4];李永夫在研究施肥對林地土壤水溶性有機(jī)碳和溫室氣體排放影響時發(fā)現(xiàn),不同施肥處理毛竹林土壤 CO2和N2O排放速率分別與土壤DOC和DON含量呈顯著的相關(guān)性[5];陳濤對施肥影響水稻土有機(jī)碳礦化的研究結(jié)果表明,土壤礦化產(chǎn)生的CO2排放速率與水溶性有機(jī)碳含量之間的相關(guān)性達(dá)到了極顯著的水平[6]。上述學(xué)者對非農(nóng)田土壤和水稻土中DOM與溫室氣體排放的關(guān)系進(jìn)行了探討,然而,在以潮土為主的農(nóng)田生態(tài)系統(tǒng)中,關(guān)于DOM對溫室氣體排放過程影響的研究尚未見報道。
基于以上分析,本研究開展室內(nèi)培養(yǎng)試驗(yàn),對添加秸稈和施氮肥條件下潮土中CO2和N2O的排放動態(tài),及其氣體排放量與溶解性有機(jī)碳氮動態(tài)之間的相關(guān)性進(jìn)行探討,旨在揭示溫室氣體的排放機(jī)理,為農(nóng)田生態(tài)系統(tǒng)的固碳減排及減緩全球溫室氣體的排放提供參考依據(jù)。
1.1 培養(yǎng)試驗(yàn)設(shè)計
培養(yǎng)試驗(yàn)所用土壤取自中國科學(xué)院禹城綜合試驗(yàn)站農(nóng)田土壤耕層,供試土壤的理化性質(zhì):有機(jī)質(zhì)15.14 g/kg、全氮 2.12 g/kg、堿解氮313.39 g/kg、速效磷127.5 mg/kg、速效鉀112.97 mg/kg、 pH值 8.4。禹城試驗(yàn)站位于黃淮海平原的魯西北黃河沖積平原,土壤類型為潮土,該區(qū)域主要采用冬小麥—夏玉米輪作制度。
培養(yǎng)試驗(yàn)設(shè)4個處理:(1)空白,即不添加秸稈和氮肥,(CK);(2)土壤中只加入秸稈,添加量為土壤質(zhì)量的2%(按照田間秸稈還田量計算),(S);(3)土壤只施用氮素,氮肥品種為尿素,氮素用量為450 kg/hm2(根據(jù)黃淮海平原的平均施肥量計算),(N);(4)土壤中加入秸稈和氮素,秸稈用量同處理2,氮素用量同處理3,(S+N)。每個處理設(shè)3次重復(fù)。秸稈理化性質(zhì):有機(jī)碳458 g/kg、全氮9.2 g/kg、C/N 49.5。
在培養(yǎng)試驗(yàn)進(jìn)行之前,先采取一定量的鮮土,風(fēng)干,過篩;將秸稈剪成1 mm×3 mm 的體積,65 ℃下烘干48 h。在培養(yǎng)試驗(yàn)時,稱取120 g風(fēng)干土樣于250 mL的錐形瓶中,加蒸餾水使其達(dá)到田間持水量的70%,預(yù)培養(yǎng)1周。預(yù)培養(yǎng)后,按上述處理加入相應(yīng)的秸稈和氮肥,將其與土壤混勻,用美國Parafilm封口膜封口,保持透氣性,在生化培養(yǎng)箱內(nèi)30 ℃恒溫培養(yǎng)[7]。每隔3—5 d檢查土壤含水量并用稱重法補(bǔ)充缺失的水分,使培養(yǎng)期間土壤含水量保持在田間持水量的70%左右。整個培養(yǎng)期342 d,共取樣14次,前期密,后期時間間隔較長。每個處理42個樣品,每次取樣時,每個處理取3個樣品作為重復(fù)。在取樣的前2h將封口膜去掉,使其與周圍環(huán)境空氣混合均勻。取樣時,用自制的取樣裝置塞住瓶口,用注射器抽取錐形瓶內(nèi)的氣體,隔2 h后,再抽取第2針氣體,在氣相色譜儀上測定計算溫室氣體的排放通量[8]。同時,將瓶內(nèi)土壤取出用于測定DOC和DON等性質(zhì)。
1.2 樣品分析與數(shù)據(jù)處理
1.2.1 DOC和DON的測定
稱取過2 mm篩的鮮土10.00 g于白色塑料瓶中,加入50 mL蒸餾水,振蕩離心,過0.45 μm的濾膜,所得澄清液為DOC浸提液[9],在liqiuⅡTOC儀上測定其濃度。DON的含量=浸提液中全氮含量-硝態(tài)氮含量-銨態(tài)氮含量,全氮的測定方法為過硫酸鉀氧化-紫外分光光度計法。
1.2.2 CO2和N2O的測定
土壤排放的CO2和N2O采用Agilent4890D氣相色譜儀,檢測器溫度為330 ℃,柱溫55 ℃,轉(zhuǎn)化器溫度375 ℃,載氣為高純氮?dú)?,?biāo)準(zhǔn)氣體購買自國家標(biāo)準(zhǔn)物質(zhì)研究中心。
1.2.3 數(shù)據(jù)處理
數(shù)據(jù)采用excel作圖,SPSS12.0進(jìn)行方差分析
2.1 CO2和N2O排放通量的動態(tài)
2.1.1 CO2的排放通量
不同處理下土壤中CO2排放通量如圖1所示,各處理的土壤CO2排放通量均表現(xiàn)出前期釋放快,后期變化平緩的排放規(guī)律。在培養(yǎng)初期土壤CO2排放通量最大,到第30天時CO2排放量急劇降低,與第7天相比,單施秸稈(S)處理CO2排放通量降低了85%,秸稈和氮肥配施(S+N)處理降低了92%,單施氮肥(N)處理降低了70%,在第45天和75天時,出現(xiàn)了2個波動小峰,可能是因?yàn)榍捌谝追纸獾奶嫉B(yǎng)分驟然減少使土壤微生物大量死亡,死亡的微生物又轉(zhuǎn)化成可利用的碳氮源,為微生物提供物質(zhì)和能量,使CO2的排放又出現(xiàn)了波動。從90天往后土壤CO2的排放量基本不變。各處理土壤CO2排放通量隨采樣時間變化的擬合方程如表1所示,為對數(shù)函數(shù)關(guān)系。
圖1 不同處理下CO2的排放通量動態(tài)Fig.1 Dynamics of CO2 emission for different treatments圖中均添加誤差線,因誤差較小,圖中顯示不明顯;內(nèi)圖縱坐標(biāo)為CO2排放通量;CK:空白,S:單施秸稈,N:單施氮肥,S+N:秸稈+氮肥
通過方差分析得出,各處理間CO2排放通量S+N>S>CK>N且差異顯著(P<0.05)。在整個培養(yǎng)期內(nèi),S+N處理的CO2排放通量在23—329 mg m-2h-1之間,排放總量比S處理高118%,是CK的637%,是N處理的851%(表2),這與秸稈和氮肥能促進(jìn)土壤有機(jī)碳的礦化過程有關(guān)。新鮮秸稈的加入為微生物提供大量的碳源,氮肥的施入使原本受到氮素營養(yǎng)限制的土壤微生物活性增強(qiáng),二者共同促進(jìn)了微生物的生長,從而加快了土壤有機(jī)碳的礦化速率,所以S+N處理的CO2排放量顯著高于其他處理的土壤,這與類似培養(yǎng)試驗(yàn)的研究結(jié)果相一致[10- 11]。單施氮肥可能導(dǎo)致微生物對碳的固定,降低了土壤有機(jī)碳的礦化率,使氮肥處理的CO2排放通量最低。
表1 不同處理下土壤CO2排放速率的回歸方程
Table 1 Equations of CO2emission under different fertilizer treatments
處理Treatments回歸方程RegressionequationR2CKy=-7.425ln(x)+48.3350.8091*Sy=-40.55ln(x)+207.280.6825*Ny=-4.64ln(x)+24.240.5767*S+Ny=-64.3ln(x)+322.20.7645*
*P<0.05的差異顯著性; CK:空白,S:單施秸稈,N:單施氮肥,S+N:秸稈+氮肥
2.1.2 N2O的排放通量
圖2 不同處理下N2O的排放通量動態(tài)Fig.2 Dynamics of N2O emission for different treatments內(nèi)圖縱坐標(biāo)為N2O排放通量,CK:空白,S:單施秸稈,N:單施氮肥,S+N:秸稈+氮肥
由圖2可知,在整個培養(yǎng)期內(nèi),CK、S+N和S處理的土壤N2O排放通量呈現(xiàn)出先增加后降低的趨勢,N處理的N2O的排放通量則呈現(xiàn)逐漸減小的趨勢。第14天時,S處理的N2O排放通量是177.69 μg m-2h-1,S+N處理的N2O排放通量是78 μg m-2h-1,到21d時S和S+N處理的排放通量急劇降低,前60d不同處理的N2O累積排放量差異顯著(P<0.05),從第60天往后,各個處理之間的N2O的排放量差異不顯著,這表明秸稈和氮肥對土壤N2O排放速率的影響隨時間的延長逐漸減弱。不同處理的N2O累積排放通量,S>N>S+N>CK處理(表2),相同氮肥添加量的情況下秸稈的施入并沒有增加N2O的排放,這與孟磊和蔡延江的研究N2O排放通量的試驗(yàn)結(jié)果相一致[12- 13]。與圖1相比,CO2排放量在第7天達(dá)到最大,此后逐漸減小,而N2O排放量則是在第14天達(dá)到最大,排放趨勢滯后于CO2,這是因?yàn)?,豐富的碳源使微生物大量繁殖,生化需氧量急劇增大,而土壤中O2含量不足形成了厭氧環(huán)境,有利于反硝化作用的進(jìn)行[14],促進(jìn)了N2O的排放。
表2 不同處理下CO2和N2O排放總量的差異
Table 2 Discrepancy of total emission of CO2and N2O under different treatments
處理TreatmentsCO2/(kg/hm2)N2O/(kg/hm2)CK261.78a136.93aS1414.22b495.75bN196.01c436.81cS+N1668.11d338.97d
同列中字母表示差異達(dá)顯著水平(P<0.05)
2.2 土壤DOC和DON動態(tài)
2.2.1 土壤DOC動態(tài)
由圖3所示,各處理土壤DOC含量呈逐漸降低的趨勢,在75 d時,S處理的土壤DOC含量急劇降低,這可能是因?yàn)榻斩捴幸追纸饨M分已被利用完畢,90 d時與CK處理的DOC含量變化基本一致,此后各處理DOC含量變化緩慢。在培養(yǎng)初期,S處理的DOC含量最高,為808.7 mg/kg,其次是S+N處理為606.5 mg/kg,N處理最低為374.1 mg/kg,到培養(yǎng)結(jié)束時,CK處理的DOC降幅為20%,S的處理的DOC降幅為77%,N處理的DOC降幅為67%,S+N的處理的DOC降幅為33%,在前60 d內(nèi),各處理DOC含量的大小為S>S+N>CK>N且差異顯著(P<0.05),在75 d以后,S處理的DOC含量迅速降低,與CK含量基本相同,在整個培養(yǎng)期內(nèi),N處理的DOC含量始終小于其他處理,這表明,秸稈能增加土壤中DOC的含量,而氮肥的施入會減少DOC的含量,這與郭銳和倪進(jìn)治的研究結(jié)果相一致[15- 16]。
圖3 土壤DOC含量動態(tài)Fig.3 Dynamics of DOC in soil for different treatments CK:空白,S:單施秸桿,N:單施氮肥,S+N:秸稈+氮肥
2.2.2 土壤DON動態(tài)
由圖4所示,CK、S和S+N處理土壤DON含量隨著培養(yǎng)時間的延長呈現(xiàn)先升高后降低的趨勢,N處理則呈現(xiàn)逐漸減小的趨勢,在培養(yǎng)末期趨于穩(wěn)定。S處理的峰值要比S+N處理落后1周,這是可能是因?yàn)榻斩挼腃/N比較高,分解速度較慢所致,N處理的DON含量在14 d時急劇降低又稍有回升后一直保持基本不變,可能是因?yàn)槟蛩刈鳛轷0窇B(tài)氮肥,微生物容易利用,快速轉(zhuǎn)化或使DON含量升高,隨著微生物對尿素的分解,DON含量降低;CK處理DON含量變化并不十分顯著。在整個培養(yǎng)時期內(nèi),DON含量S+N>S>N>CK,處理之間差異顯著(P<0.05),S+N處理的DON含量比S處理高27.3%,比N處理高47.6%,這表明秸稈和氮肥配施能顯著增加土壤DON的含量,秸稈對DON含量的影響比氮肥顯著。
圖4 土壤DON含量動態(tài)Fig.4 Dynamics of DON in soil for different treatmentsCK:空白,S:單施秸桿,N:單施氮肥,S+N:秸稈+氮肥
2.3 DOM對氣體排放通量的影響
對土壤DOC和DON含量與氣體排放通量之間的相關(guān)性進(jìn)行分析,結(jié)果表明(表3),土壤DOC和DON含量變化與CO2和N2O的排放通量呈顯著的相關(guān)性,這說明,溶解性有機(jī)碳氮的含量與溫室氣體的排放關(guān)系密切。在碳氮轉(zhuǎn)化過程中,溶解性有機(jī)碳氮既是微生物的分解產(chǎn)物,同時也是微生物可利用的碳氮源,其含量變化在一定程度上能影響CO2和N2O的排放速率。
3.1 養(yǎng)分輸入對CO2、N2O排放過程和DOM含量的影響
本試驗(yàn)中,CO2排放通量和DOC含量在培養(yǎng)前期較高隨培養(yǎng)時間延長而降低的原因是,玉米秸稈含有大量的水溶性有機(jī)物質(zhì),施入土壤后,為微生物提供了豐富的物質(zhì)和能源,微生物數(shù)量迅速增加,土壤呼吸速率急劇升高,釋放出大量的CO2,隨著培養(yǎng)時間的延長,水溶性物質(zhì)逐漸被消耗,DOC含量減小,微生物體大量死亡,土壤呼吸速率驟然降低,在培養(yǎng)后期,微生物的數(shù)量、可利用的碳氮源處于平衡狀態(tài),此時,DOC含量和CO2排放通量基本保持不變。這與前人研究結(jié)果基本一致,Troyer在研究添加玉米秸稈對土壤呼吸速率的影響時指出,添加玉米秸稈后,土壤中CO2累積量隨培養(yǎng)時間的延長而增加,DOC含量隨時間的延長逐漸降低后基本保持不變[17]。Blagodatskaya在研究添加不同濃度的葡糖糖對土壤呼吸作用的影響時發(fā)現(xiàn),不同處理的CO2排放通量在前3d達(dá)到最大,后逐漸降低,在培養(yǎng)末期保持不變,DOC含量則呈現(xiàn)逐漸降低的趨勢[18]。薛菁芳在研究玉米秸稈加入棕壤后溶解性有機(jī)碳氮的變化時發(fā)現(xiàn),土壤中DON含量在培養(yǎng)前期逐漸上升后期逐漸下[19],這與仇少君對淹水條件下稻草與硫酸銨配施處理的土壤DON含量動態(tài)的研究結(jié)果相近[20]。本試驗(yàn)中,S+N和S處理的DON含量均先增大,后逐漸降低至穩(wěn)定,與薛菁芳和仇少軍的研究結(jié)果一致,這可能是因?yàn)?,有機(jī)物料和氮肥的施入刺激了土壤微生物的繁殖,促進(jìn)了對秸稈的分解,DON作為有機(jī)物料的分解產(chǎn)物,含量逐漸升高,此后,又作為微生物可利用的氮源被逐漸分解,含量降低趨于穩(wěn)定。
表3 土壤DOC、DON含量與CO2、N2O排放通量的相關(guān)性
Table 3 Correlation between DOC, DON and CO2, N2O emission in soil
處理TreatmentsR2CO2與DOCN2O與DONCK0.718*0.826*S0.898*0.620*N0.658*0.792*S+N0.885*0.725*
*P<0.05的差異顯著性
3.2 DOM對CO2、N2O排放過程的影響
土壤有機(jī)碳的礦化是土壤中重要的生物學(xué)過程,秸稈添加必然會引起微生物活動的改變,從而影響了有機(jī)碳氮組分的變化,對有機(jī)碳的礦化產(chǎn)生重要影響。Yoshitaka研究表明,種植大豆土壤的呼吸速率與DOC含量密切相關(guān)[28]。Stephan研究發(fā)現(xiàn),在沼澤土壤中,DOC的組成影響了土壤呼吸速率,CO2的釋放量與芳香族化合物含量和復(fù)雜的DOC分子有關(guān)[3]。陳濤等指出,不同施肥處理下土壤中DOC含量與土壤有機(jī)碳的礦化量呈顯著的相關(guān)性[5]。在本試驗(yàn)中,CO2的排放通量與DOC含量呈顯著相關(guān)性,相關(guān)系數(shù)(R2)在0.6以上,這表明土壤CO2的排放通量與DOC含量的動態(tài)變化有密切關(guān)系,主要是因?yàn)镈OC是微生物較容易利用的底物。
(1)秸稈施入土壤后,隨著培養(yǎng)時間的延長,各處理的CO2排放通量和土壤DOC的含量均表現(xiàn)出了逐漸降低的趨勢,且培養(yǎng)前期降低幅度較大,然后緩慢減小,培養(yǎng)后期基本保持不變,不同處理間的差異顯著。S處理和S+N處理的N2O排放通量和土壤DON含量變化呈現(xiàn)先增大后減小的規(guī)律,單施氮肥處理的N2O和土壤DON含量隨培養(yǎng)時間的延長逐漸降低。
(2)秸稈和氮肥的配施比單施秸稈顯著促進(jìn)CO2的排放,單施秸稈的土壤N2O排放通量和土壤DOC含量顯著高于其他處理,單施氮肥的CO2排放通量和DOC含量顯著低于CK處理,這表明單施氮肥能降低土壤CO2排放通量和土壤DOC的含量。
(3)不同處理下土壤的CO2排放通量和DOC含量、N2O排放通量和土壤DON含量呈顯著相關(guān)性,表明土壤DOC和DON與農(nóng)田溫室氣體排放密切相關(guān)。
[1] Song L N, Zhang Y M, Hu C S, Zhang X Y, Dong W X, Wang Y Y, Qin S P. Comprehensive analysis of emissions and global warming effects of greenhouse gases in winter-wheat fields in the high-yield agro-region of North China Plain. Chinese Journal of Eco-Agriculture, 2013, 21(3): 297- 307.
[2] Magill A H, Aber J D. Variation in soil net mineralization rates with dissolved organic carbon additions. Soil Biology and Biochemistry, 2000, 32(5): 597- 601.
[3] Glatzel S, Kalbitz K, Dalva M, Moore T. Dissolved organic matter properties and their relationship to carbon dioxide efflux from restored peat bogs. Geoderma, 2003, 113(3/4): 397- 411.
[4] Chow A T, Tanji K K, Gao S D, Dahlgren R A. Temperature, water content and wet-dry cycle effects on DOC production and carbon mineralization in agricultural peat soils. Soil Biology and Biochemistry, 2006, 38(3): 477- 488.
[5] Li Y F, Jiang P K, Liu J, Wang X D, Wu J S, Ye G P, Zhou G M. Effect of fertilization on water-soluble organic C, N and emission of greenhouse gases in the Soil ofPhyllostachysedulisStands. Scientia Silvae Sinicae, 2010, 46(12): 165- 170.
[6] Chen T, Hao X H, Du L J, Lin S, Feng M L, Hu R G, Gao J Y. Effects of long-term fertilization on paddy soil organic carbon mineralization. Chinese Journal of Applied Ecology, 2008, 19(7): 1494- 1500.
[7] Qi Y C, Dong Y S. Nitrous oxide emissions from soil and some influence factors. Acta Geographica Sinica, 1999, 54(6): 535- 541.
[8] Li Y C, Song C C, Hou C C, Wang X W, Sun X X. Effects of exogenous nitrogen availability on carbon mineralization of different wetland soil types in Northeast China. Acta Geographica Sinica, 2011, 12(31): 1480- 1486.
[9] Yan D Z, Wang D J, Sun R J, Lin J H. N mineralization as affected by long-term N fertilization and its relationship with crop N uptake. Pedosphere, 2006, 16(1): 125- 130.
[10] Huang J, Liu H B, Wang B R. CO2,N2O Emission from red soil dry-land under long-term fertilization. Chinese Agricultural Science Bulletin, 2009, 25(24): 428- 433.
[11] Ye D Z, Wang D J. Carbon and nitrogen mineralization affected by long-term application of chemical fertilizer and rice straw in paddy soil. Soil, 2011, 43(4): 529- 533.
[12] Cai Y J, Wang L F, Wen L Y, Xie H T, Zhang X D. Nitrous oxide emission from long-term fertilized black soil by laboratory incubation. Journal of Agro-Environment Science, 2008, 27(2): 617- 621.
[13] Meng L, Ding W X, Cai Z C. Effects of long-term fertilization on N distribution and N2O emission in fluvo-aquci soil in North China. Acta Ecologica Sinica, 2008, 28(12): 6197- 6230.
[14] Meng L, Ding W X, Cai Z C. Long-term application of organic manure and nitrogen fertilizer on N2O emissions, soil quality and crop production in a sandy loam soil. Soil Biology and Biochemistry, 2005, 37(11): 2037- 2045.
[15] Guo R, Wang J K, Li Y S. Effect of the long-term mulching and different treatments on dissolved organic carbon in brown soil. Journal of Anhui Agricultural Sciences, 2007, 35(9): 2672- 267.
[16] Ni J Z, Xu J M, Xie Z M, Wang D J. Contents of wsoc and characteristics of its composition under different fertilization systems. Acta Pedologica Sinica, 2003, 40(5): 724- 729.
[17] de Troyer I, Amery F, van Moorleghem C, Smolders E, Merckx R. Tracing the source and fate of dissolved organic matter in soil after incorporation of a13C labelled residue A batch incubation study. Soil Biology and Biochemistry, 2011, 43(3): 513- 519.
[18] Blagodatskaya E, Yuyukina T, Blagodatsky S, Kuzyakov Y. Three-source-partitioning of microbial biomass and of CO2efflux from soil to evaluate mechanisms of priming effects. Soil Biology and Biochemistry, 2011, 43(4): 778- 786.
[19] Xue J F, Chen B Q, Wang J K. Effect of maize residues on dissolved organic nitrogen and dissolved inorganic nitrogen in brown earth. Heilongjiang Agriculture Sciences, 2011, (4): 41- 45.
[20] Chou S J, Peng P Q, Rong X M. Dynamics of soil microbial biomass and dissolved organic carbon and nitrogen under flooded condition. Chinese Journal of Applied Ecology, 2006, 17(11): 2052- 2058.
[21] Yan L L, Zhang F S, Mao R G, Gao Q, Ju X T. Soil net N and C mineralization and urea transformation in agroecosystems across North China Plain. Plant Nutrition and Fertilizer Science, 2007, 13(5): 824- 830.
[22] Zhu X, Han Z X, Qiao Y F, Wang S Y. Influence of soluble carbon and nitrogen on N2O emission from different thermal zones soil. Journal of Agro-Environment Science, 2009, 28(12): 2637- 2644.
[23] Lin X, Ju X T, Zhang L J, Wan Y J, Liu S Q. Effects of different fertilization modes on soil ammonia volatilization and nitrous oxide emission. Chinese Journal of Applied Ecology, 2008, 19(1): 99- 104.
[24] Xie B L, Wu J S, Xu Q F, Jiang P K. Effect of different fertilization and mulching on water soluble organic of the soil under phyllostachy praecox stands. Acta Pedologica Sinica, 2009, 46(6): 1169- 1171.
[25] Bowden R D, Davidson E, Savage K, Arabia C, Steudler P. Chronic nitrogen additions reduce total soil respiration and microbial respiration in temperate forest soils at the Harvard Forest. Forest Ecology and Management, 2004, 196(1): 43- 56.
[27] Meijide A, Cárdenas L M, Sánchez-Martín L, Vallejo A. Carbon dioxide and methane fluxes from a barley field amended with organic fertilizers under Mediterranean climatic conditions. Plant and Soil, 2010, 328(1/2): 353- 367.
[28] Yoshitaka U, Nishimura S, Akiyama H. The relationship of water-soluble carbon and hot-water-soluble carbon with soil respiration in agricultural fields. Agriculture, Ecosystem and Environment, 2012, 156: 116- 122.
[29] Zhao M X, Kalbitz K, Zhou J B. Dynamics of soluble organic nitrogen and its relation to mineralization of soil organic nitrogen during incubation of several soils in Loess Region. Journal of Soil and Water Conservation, 2008, 22(4): 122- 127.
參考文獻(xiàn):
[1] 宋利娜, 張玉銘, 胡春勝, 張喜英, 董文旭, 王玉英, 秦樹平. 華北平原高產(chǎn)農(nóng)區(qū)冬小麥農(nóng)田土壤溫室氣體排放及其綜合溫室效應(yīng). 中國生態(tài)農(nóng)業(yè)學(xué)報, 2013, 21(3): 297- 307.
[5] 李永夫, 姜培坤, 劉娟, 王旭東, 吳家森, 葉耿平, 周國模. 施肥對毛竹林土壤水溶性有機(jī)碳氮與溫室氣體排放的影響. 林業(yè)科學(xué), 2010, 46(12): 165- 170.
[6] 陳濤, 郝曉輝, 杜麗君, 林杉, 馮明磊, 胡榮桂, 高瓃贇. 長期施肥對水稻土土壤有機(jī)碳礦化的影響. 應(yīng)用生態(tài)報, 2008, 19(7): 1494- 1500.
[7] 齊玉春, 董云社. 土壤氧化亞氮產(chǎn)生、排放及其影響因素. 地理科學(xué), 1999, 54(6): 535- 541.
[8] 李英臣, 宋長春, 侯翠翠, 王憲偉, 孫曉新. 氮可利用性對東北不同類型濕地土壤有機(jī)碳礦化的影響. 地理科學(xué), 2011, 12(31): 1480- 1486.
[10] 黃晶, 劉洪斌, 王伯仁. 長期施肥下紅壤旱地CO2、N2O排放特征. 中國農(nóng)學(xué)通報, 2009, 25(24): 428- 433.
[11] 閆德智, 王德建. 長期施用化肥和秸稈對水稻土碳氮礦化的影響. 土壤, 2011, 43(4): 529- 533.
[12] 蔡延江, 王連峰, 溫麗燕, 解宏圖, 張旭東. 培養(yǎng)實(shí)驗(yàn)研究長期不同施肥制度下中層黑土氧化亞氮的排放特征. 農(nóng)業(yè)環(huán)境科學(xué)學(xué)報, 2008, 27(2): 617- 621.
[13] 孟磊, 蔡祖聰, 丁維新. 長期施肥對華北典型潮土N分配和N2O排放的影響. 生態(tài)學(xué)報, 2008, 28(12): 6197- 6230.
[15] 郭銳, 汪景寬, 李雙異. 長期地膜覆蓋及不同施肥處理對棕壤水溶性有機(jī)碳的影響. 安徽農(nóng)業(yè)科學(xué), 2007, 35(9): 2672- 2673.
[16] 倪進(jìn)治, 徐建民, 謝正苗, 王德建. 不同施肥處理下土壤水溶性有機(jī)碳含量及其組成特征的研究. 土壤學(xué)報, 2003, 40(5): 724- 729.
[19] 薛菁芳, 陳書強(qiáng), 汪景寬. 玉米秸稈對棕壤中可溶性有機(jī)碳和無機(jī)氮的影響. 黑龍江農(nóng)業(yè)科學(xué), 2011, (4): 41- 45.
[20] 仇少君, 彭佩欽, 榮湘民. 淹水培養(yǎng)條件下土壤微生物生物量碳_氮和可溶性有機(jī)碳_氮的動態(tài). 應(yīng)用生態(tài)學(xué)報, 2006, 17(11): 2052- 2058.
[21] 楊莉琳, 張福鎖, 毛仁釗, 高強(qiáng), 巨曉棠. 華北平原農(nóng)田生態(tài)系統(tǒng)土壤C、N凈礦化及尿素轉(zhuǎn)化研究. 植物營養(yǎng)與肥料學(xué)報, 2007, 13(5): 824- 830.
[22] 朱霞, 韓曉增, 喬云發(fā), 王守宇. 外加可溶性碳氮對不同熱量帶土壤N2O排放的影響. 農(nóng)業(yè)環(huán)境科學(xué)學(xué)報, 2009, 28(12): 2637- 2644.
[23] 李鑫, 巨曉棠, 張麗娟, 萬云靜, 劉樹慶. 不同施肥方式對土壤氨揮發(fā)和氧化亞氮排放的影響. 應(yīng)用生態(tài)學(xué)報, 2008, 19(1): 99- 104.
[24] 謝秉樓, 吳家森, 徐秋芳, 姜培坤. 覆蓋與施肥處理對雷竹林土壤水溶性有機(jī)氮的影響. 土壤學(xué)報, 2009, 46(6): 1169- 1171.
[29] 趙滿興, Kalbitz K, 周建斌. 黃土區(qū)幾種土壤培養(yǎng)過程中可溶性有機(jī)氮的變化及其與土壤礦化氮的關(guān)系. 水土保持學(xué)報, 2008, 22(4): 122- 127.
Effects of dissolved organic matter in soil on the emission of CO2and N2O
LI Binbin1,2,MA Junhua1,*,WU Lanfang1
1KeyLaboratoryofEcosystemNetworkObservationandModeling,InstituteofGeographicSciencesandNaturalResourcesResearch,ChineseAcademyofSciences,Beijing, 100101,China2QingDaoAgriculturalUniversity,Qingdao,266105,China
Agricultural soil is the main emission source of greenhouse gas. Dissolved organic matter (DOM) in agricultural soil is the labile component of organic matter and the most available substrates for microbial. Its concentration and dynamic change is closely related to the production and emission of greenhouse gas. The aim of this study was to estimate the effect of soil DOM concentration on the emission of CO2and N2O after materials addition. And the relationship between the dynamics of DOM concentration and the emission of CO2and N2O was evaluated after that. An incubation experiment was adopted in this study with the soil sampled from the tillage layer in the field at Yucheng comprehensive experimental station, Chinese Academy of Sciences. Four treatments, which were soil with or without material addition, i.e., straw only (S), nitrogen only (N), straw with nitrogen (S+N), and control (CK), respectively, were set. The amount of these added materials in this study was estimated based on the conventional application of N fertilizer and straw return in the North China Plain. The emissions of CO2and N2O, and the concentrations of dissolved organic carbon and nitrogen (DOC/DON) were measured at different time interval during the 342 days incubation. The results showed that there was significant difference between these four treatments (P<0.05) for the concentration of DOM and the emissions of CO2and N2O. It presented a gradually decreasing trend in the emission of CO2and the concentration of DOC in soil for all these four treatments. However, the emission of N2O and the concentration of DON increased at first and then decreased with time for these two treatments of S and S+N. In addition, the treatment of S+N showed the highest average concentration of DOC and DON. The lowest mean concentration of DOC and DON was found in the treatment of N and CK, respectively. In the treatment of S+N added with N fertilizer and corn straw, the cumulative CO2emission was 1668.11kg/hm2during the incubation period, which was much higher than the other three treatments. In the treatment of N added with N fertilizer only, the cumulative CO2emission was 196.01kg/hm2, which was much lower than the other three treatments. The highest cumulative N2O emission, 495.75g hm-2, was found in the treatment of S with the addition of straw only, and the lowest cumulative N2O emission, 136.93 g hm-2, was found in the treatment of CK. A logarithmic equation was fitted between CO2emission and the time for each treatment (R2>0.57,P<0.05). There was a significant correlation between the emission of CO2and the concentration of DOC(R2>0.65). It also happened between the emission of N2O and the concentration of DON in soil (R2>0.62), indicated that the concentration and dynamics of DOC and DON in soil caused by the addition of straw and N fertilizer had a significant influence on the emission of CO2and N2O.
dissolved organic carbon; dissolved organic nitrogen; greenhouse gas; straw; N fertilizer;
國家自然科學(xué)基金(31271675); 國家科技支撐計劃(2007BAD89- 2)
2012- 12- 20; 網(wǎng)絡(luò)出版日期:2014- 03- 04
10.5846/stxb201212201835
*通訊作者Corresponding author.E-mail: majh@igsnrr.ac.cn
李彬彬,馬軍花,武蘭芳.土壤溶解性有機(jī)物對CO2和N2O排放的影響.生態(tài)學(xué)報,2014,34(16):4690- 4697.
Li B B,Ma J H,Wu L F.Effects of dissolved organic matter in soil on the emission of CO2and N2O.Acta Ecologica Sinica,2014,34(16):4690- 4697.