劉 楊 劉曉宇 石春林 宣守麗 孫 彬
(1 農(nóng)業(yè)信息研究所/農(nóng)業(yè)部長江下游平原農(nóng)業(yè)環(huán)境重點實驗室,江蘇省農(nóng)業(yè)科學(xué)院,南京 210014)
(2 土壤與農(nóng)業(yè)可持續(xù)發(fā)展國家重點實驗室(中國科學(xué)院南京土壤研究所),南京 210008)
生物炭緩解稻麥輪作區(qū)小麥漬害脅迫的作用*
劉 楊1,2劉曉宇2石春林1?宣守麗1孫 彬1
(1 農(nóng)業(yè)信息研究所/農(nóng)業(yè)部長江下游平原農(nóng)業(yè)環(huán)境重點實驗室,江蘇省農(nóng)業(yè)科學(xué)院,南京 210014)
(2 土壤與農(nóng)業(yè)可持續(xù)發(fā)展國家重點實驗室(中國科學(xué)院南京土壤研究所),南京 210008)
稻麥輪作是長江中下游地區(qū)最主要的糧食生產(chǎn)方式,然而在該地區(qū)季風(fēng)氣候的背景下,小麥生長季易發(fā)生漬害脅迫,導(dǎo)致小麥減產(chǎn)甚至絕收。施用生物炭是一種有效的土壤改良方式,目前,已在長江中下游稻麥輪作區(qū)開展應(yīng)用研究,但定量評估施用生物炭對長江中下游地區(qū)小麥漬害的影響研究尚未見報道。開展土柱和小區(qū)試驗,研究水稻秸稈生物炭對稻麥輪作土壤和小麥生長前期的影響。結(jié)果表明,施用生物炭能顯著降低稻麥輪作土壤的容重。不同深度的土壤水分動態(tài)變化也表明,施用生物炭有利于土壤水分向下遷移,可改善稻麥輪作土壤排水不暢的特點。同時,與未施用生物炭的處理相比,施用10 t hm-2生物炭能加快小麥出苗,促進小麥生長。播種后90 d的采樣結(jié)果顯示,施用生物炭處理下小麥株高、主根長和最后一片完全葉的葉綠素相對含量(SPAD值)均顯著高于對照(p<0.05)。根系特征顯示,施用生物炭處理下的小麥主根長雖然顯著高于對照,但2個處理間的總根長和總根面積卻無顯著差異。綜上,施用生物炭能顯著改善稻麥輪作土壤的排水條件,促進小麥前期生長,將有助于小麥在關(guān)鍵生育期抵御漬害脅迫。
稻麥輪作;生物炭;漬害脅迫;土壤物理性質(zhì);土柱試驗
稻麥輪作是長江中下游地區(qū)最主要的糧食生產(chǎn)方式[1],種植面積達到1 300萬hm2[2],但這種水旱輪作制度往往導(dǎo)致土壤黏重、土壤排水性差[3]。在水稻生長季,稻麥輪作土壤較好的保水能力可節(jié)省水資源,提高水分利用效率,而小麥生長季一旦降雨過多,土壤水分難以排出,將導(dǎo)致嚴(yán)重的小麥漬害減產(chǎn)。受季風(fēng)氣候影響,每年3至5月為長江中下游地區(qū)陰雨多發(fā)季節(jié)[4],降水量往往超過小麥生長季的總需水量[5],是小麥漬害的高發(fā)時段。據(jù)報道[6-7],不同程度的漬害脅迫可造成小麥減產(chǎn)20%~50%。因此,漬害是長江中下游地區(qū)小麥生產(chǎn)面臨的最主要的氣象災(zāi)害之一,探索合理的方法降低小麥漬害減產(chǎn)對當(dāng)?shù)丶Z食安全有重要意義。
目前,應(yīng)對小麥漬害減產(chǎn)的方法主要包括農(nóng)田排水、漬后補施肥料及施用生長調(diào)節(jié)劑等[8-10]。這些方法主要分為兩類,一類以土壤為處理對象,如加速排水、維持土壤肥力;另一類以作物為處理對象,如提高作物自身耐漬能力和漬后恢復(fù)能力。但農(nóng)田排水成本較高,需要持續(xù)投入和維護[10];而補施肥料和使用生長調(diào)節(jié)劑,不但增加成本,且易造成面源污染[11]。在實際生產(chǎn)中,探索成本較低、環(huán)境友好的新方法具有重要意義。
生物炭(Biochar)是一種優(yōu)良的土壤改良劑。生物炭是在完全或部分缺氧條件下,經(jīng)熱解產(chǎn)生的一種含碳量豐富、性質(zhì)穩(wěn)定的有機物質(zhì),具有多孔結(jié)構(gòu)、低容重、高 pH等特征[12]。鑒于以上特性,生物炭在近年來被廣泛用于改善土壤板結(jié)[13-14]、提高土壤碳固存[15]等。此外,相比秸稈直接還田,秸稈制成生物炭還田具有甲烷排放少以及不影響后續(xù)耕作、播種等優(yōu)勢[16]。目前,生物炭已在長江中下游稻麥輪作區(qū)開展應(yīng)用研究[17]。但水稻秸稈生物炭對小麥生長,尤其是漬害脅迫背景下小麥生長的影響研究尚鮮見報道。已有研究表明,生物炭的多孔結(jié)構(gòu)和低容重的特點有利于降低土壤容重、提高土壤孔隙度[14]。Peake等[13]針對8種類型土壤的研究表明,當(dāng)生物炭施用量達到2.5%(w/w,生物炭與土壤的質(zhì)量比)時,土壤容重下降4.2%~19.2%。Oguntunde等[18]采樣調(diào)查的結(jié)果表明,施用生物炭使土壤容重降低9%。劉園等[19]在封丘開展的小區(qū)試驗也表明,施用生物炭對土壤容重、水分、持水量等物理性狀的改善可能是作物增產(chǎn)的重要原因。以上研究均表明,施用生物炭可降低土壤容重,增加土壤通氣性[20],進而改良土壤結(jié)構(gòu)[21]。因此,施用生物炭可能成為緩解小麥漬害脅迫的方法。然而,生物炭如何影響稻麥輪作土壤容重和土壤水分動態(tài)變化,能否改善土壤物理性質(zhì)以解除土壤漬水狀態(tài),進而影響該種植制度下的小麥生產(chǎn)?相關(guān)研究尚較為缺乏。本研究通過開展土柱和小區(qū)試驗,探索生物炭對稻麥輪作土壤和小麥前期生長的影響,為綜合評價施用生物炭能否作為緩解小麥漬害脅迫的方法做前期評估。
試驗土壤取自江蘇省農(nóng)科院試驗場附近(32°02′N,118°52′28″E)的稻麥輪作土壤(土壤類型為潴育型水稻土,質(zhì)地為黏壤土),土壤容重為1.15 g cm-3,pH為 6.58。水稻秸稈生物炭購自江蘇華豐公司,原料為水稻秸稈,燒制溫度為500℃,容重為0.48 g cm-3。
2016年10月在江蘇省農(nóng)科院實驗室內(nèi)開展土柱試驗,實驗室溫度控制在20℃。采用內(nèi)徑20 cm,高80 cm的聚氯乙烯(PVC)管制作土柱。分別在10、20和40 cm深處開一直徑3 cm圓口,用于布設(shè)EC-5土壤水分傳感器(Decagon Devices,美國)。PVC管底部鉆取3個直徑1 cm的圓口用于排水。試驗共設(shè)置3個處理:生物炭施用量為0、10和40 t hm-2,使用收集的稻麥輪作土壤對20~80 cm深度的土柱進行填充,土壤和生物炭按比例混合后對0~20 cm深度的土柱進行填充。土柱裝配完成后,將土壤水分調(diào)節(jié)至60%田間持水量,土壤水分達到平衡后維持7 d,之后模擬一次達到漬害水平的降水(40 mm),記錄降水前后各層土壤的體積含水量,記錄間隔為5 min。
2016年11月在江蘇省農(nóng)科院試驗場開展小區(qū)試驗,小區(qū)大小為1.5 m×4.0 m。設(shè)置對照(CK,未施用生物炭)和施用生物炭(BC,施用量為10 t hm-2)2個處理,生物炭施用深度為0~20 cm,每處理均設(shè)置3個重復(fù)。小麥供試品種為寧麥13號。播種期為11月14日,采用行播的方式進行播種,每個小區(qū)播種7行,行距為20 cm,播種密度約為400粒 m-2。小區(qū)實行常規(guī)水肥管理,基肥施用量為純氮135 kg hm-2(以復(fù)合肥的形式)。每個處理隨機選取6株苗,用于監(jiān)測小麥生長狀況,每隔7 d左右記錄小麥的葉齡和莖蘗數(shù)。小麥播種后90 d,對2個處理下的小麥進行取樣分析,獲取小麥各器官干物質(zhì)重,同時測定小麥最后一片完全葉的葉綠素相對含量(SPAD)值,以及小麥主根長、總根長和總根面積。
使用EC-5土壤水分傳感器記錄土柱試驗?zāi)M降水前后的土壤體積含水量,用模擬降水后的土壤體積含水量減去對應(yīng)模擬降水前土壤水分平衡時的土壤體積含水量,獲取土壤體積含水量變化量,用來描述降水后土壤水分動態(tài)變化。土柱模擬降水結(jié)束48 h后,在土柱10 cm深處,用環(huán)刀法測取土壤容重[22]。
播種后90 d對小區(qū)試驗2個處理下的小麥植株進行取樣,每個處理隨機選取6株小麥,按根、莖、葉分樣,105℃殺青30 min,80℃烘干至恒重,獲取小麥各器官的干物質(zhì)重。此外,采用葉綠素測定儀(SPAD-502,Minolta,日本),在小麥最后一片完全葉的中間部分測量4次,獲取的平均值作為小麥葉片SPAD值,每個處理各選取5片葉片進行測量。采用WinRHIZO根系分析系統(tǒng)(Regent Instruments,Québec,加拿大),對小麥根系進行掃描,獲取小麥總根長和總根面積,每個處理各選取5株小麥根系進行測量。
采用方差分析比較土柱試驗和小區(qū)試驗中不同處理間的差異,均值的多重比較采用最小顯著差異法(LSD)檢驗,p<0.05作為顯著性差異的標(biāo)準(zhǔn),統(tǒng)計分析使用SPSS 19.0進行。采用Origin 9.0進行制圖。
稻麥輪作土壤具有質(zhì)地黏重、容重較大的特點,本研究中未經(jīng)處理的稻麥輪作土壤容重達到1.15 g cm-3。當(dāng)生物炭施用量達到10和40 t hm-2時,土壤容重相比對照分別下降7.4%和11.4%,均達到顯著水平(p<0.05)(圖1)。表明施用生物炭可降低土壤容重,改善稻麥輪作土壤較為黏重、緊實的特點。
圖1 土柱試驗中不同生物炭施用量下土壤容重變化Fig. 1 Variation of bulk density relative to application rate in soil column experiment
土柱試驗中,土壤水分動態(tài)變化表明,生物炭對不同層次土壤水分有不同影響(圖2)。降水發(fā)生后,對照處理的10 cm土壤水分下降速度在初期(400 min內(nèi))低于施用生物炭的處理,表明相比對照,施用生物炭有利于土壤水分下滲。但模擬降水720 min左右,對照處理10 cm土壤水分繼續(xù)下降,而施用生物炭處理下10 cm土壤水分變化較小。20 cm土壤水分的動態(tài)變化顯示,對照處理20 cm土壤水分顯著高于施用生物炭的處理。稻麥輪作土壤質(zhì)地黏重,且在20 cm左右易出現(xiàn)緊實的犁底層,不利于土壤水分向下遷移。本試驗的觀測結(jié)果也顯示,對照處理20 cm土壤水分在模擬降水后24 h內(nèi),明顯高于施用生物炭的處理。生物炭處理20 cm土壤水分下降速度高于對照,在模擬降水60 min后,生物炭處理20 cm土壤水分已明顯低于對照,表明施用生物炭可改善20 cm深度土壤的排水能力。相比10 cm和20 cm兩個深度,各處理40 cm土壤水分動態(tài)變化趨勢較為一致,無顯著差異。
小區(qū)試驗中,小麥生長前期監(jiān)測結(jié)果顯示,施用生物炭有利于小麥出苗。與對照(CK)相比,施用10 t hm-2生物炭的處理下(BC),小麥出苗時間提前3 d。此外,施用生物炭處理的小麥葉齡和莖蘗數(shù)也略高于對照,但兩者之間的差異在播種后90 d內(nèi)尚未達到顯著水平(p>0.05,n=6)(圖3)。
小麥播種后90 d,2個處理隨機選取6株小麥進行破壞采樣。采樣結(jié)果顯示,生物炭處理下小麥的株高和主根長均顯著高于對照(p<0.05,n=6)(圖4)。生物炭處理下的小麥莖和葉干重略高于對照,而根干重略低于對照,但處理間的差異均未達到顯著水平(p>0.05,n=6)(數(shù)據(jù)未列出)。
使用SPAD-502葉綠素測定儀,在播種后90 d獲取不同處理下小麥最后一片完全葉的SPAD值,結(jié)果表明,施用生物炭處理下小麥SPAD值顯著高于對照處理(p<0.05,n=5)(圖5),表明施用生物炭有助于提高小麥葉片葉綠素含量。
使用WinRHIZO根系分析系統(tǒng),在播種后90 d獲取不同處理下的小麥根系特征。結(jié)果顯示,雖然生物炭處理下小麥主根長顯著高于對照(圖4),但總根長和總根面積卻不存在顯著差異(p>0.05,n=5)(圖6)。
圖2 不同生物炭施用量下不同深度(10、20、40 cm)土壤體積含水量動態(tài)變化Fig. 2 Dynamic change of soil volumetric water content at different soil depths(10 cm,20 cm,40 cm)relative to biochar application rate
圖3 不同生物炭處理下小麥葉齡和莖蘗數(shù)變化Fig. 3 Variation of leaf age and number of tillers relative to biochar application rate
圖4 播種后90 d不同生物炭處理下小麥株高和主根長Fig. 4 Plant height and taproot length of the plant 90 days after sowing relative to biochar application rate
圖5 播種后90 d不同生物炭處理下小麥葉片葉綠素相對含量值Fig. 5 Chlorophyll relative content(SPAD values)of wheat leaves of the plant 90 days after sowing relative to biochar application rate
圖6 播種后90 d不同生物炭處理下小麥總根長和總根面積Fig. 6 Total root length and total root area of the plant 90 days after sowing relative to biochar application rate
前人研究[23]認(rèn)為,土壤表層保持長時間積水,或土壤表層的有效水分較田間持水量高20%以上時,土壤達到漬水條件。水稻種植往往導(dǎo)致土壤透氣性和排水性差[3],使得稻麥輪作土壤易達到漬水條件,在小麥生長季易發(fā)生漬害脅迫,導(dǎo)致小麥減產(chǎn)。因此,對質(zhì)地較為黏重的稻麥輪作土壤進行改良,改善其排水能力,將有助于降低小麥漬害脅迫減產(chǎn)。已有研究表明,生物炭的多孔結(jié)構(gòu)有利于降低土壤容重、提高土壤孔隙度[14]。本研究的結(jié)果也證明,施用水稻秸稈生物炭可顯著降低土壤容重(圖1),與前人研究結(jié)果一致[13]。當(dāng)施用量達到10 t hm-2時,土壤容重下降7.4%,達到顯著水平。當(dāng)施用量增加至40 t hm-2時,土壤容重進一步下降。前人研究認(rèn)為,生物炭具備較強的吸附能力,有利于改善土壤的保水能力,因此,生物炭最早用于干旱地區(qū)質(zhì)地較粗土壤。而本研究的結(jié)果表明,生物炭同樣可用于改善質(zhì)地黏重的土壤。土壤水分動態(tài)變化的觀測結(jié)果(圖2)表明,施用生物炭有利于10 cm和20 cm土壤水分向下遷移。這主要是因為,生物炭具有疏松、多孔的結(jié)構(gòu),與土壤混合后,可增加土壤通氣性[24],進而改善土壤排水能力[21]。因此,施用生物炭具備加速解除土壤漬水狀態(tài)的潛力。此外,10 cm土壤水分動態(tài)變化的數(shù)據(jù)顯示,生物炭一方面可促進排水,另一方面起到了土壤水分容器的作用。當(dāng)水分過多時,生物炭可吸收一部分土壤水分,而水分下降到一定程度時,生物炭可釋放之前吸收的水分,使土壤水分總體達到一個相對平衡的狀態(tài)。進一步證明,生物炭作為一種優(yōu)良的土壤改良劑,可同時適用于質(zhì)地較粗和質(zhì)地黏重的土壤。
土壤漬水后,土壤中的氧氣快速下降,抑制根系的有氧呼吸,從而影響根系生長[25]。Malik等[26]采用盆栽試驗的方法,研究不同持續(xù)時間漬害對小麥根系的影響,結(jié)果表明,漬害脅迫期間,小麥的種子根生長停滯,氣根長度也受到抑制。因此,漬害脅迫往往抑制小麥根系生長。而前人研究[27]認(rèn)為,施用生物炭有助于作物根系生長。張偉明等[28]開展的盆栽試驗表明,施用生物炭能增加水稻生育前期根系的主根長、根體積和根鮮重,在一定程度上延緩根系衰老。這主要是因為,生物炭的多孔結(jié)構(gòu)能降低土壤容重,提高土壤孔隙度[18],為根系生長提供較好環(huán)境,有利于根系深扎。本研究的試驗結(jié)果也表明,施用生物炭顯著降低土壤容重,促進根系深扎,因此,生物炭處理下小麥主根長顯著高于對照(圖4)。但2個處理間總根長和總根面積并無顯著差異(圖6),這可能是因為,生物炭處理下,小麥根系深扎可獲取足夠的水分,而對照處理下稻麥輪作土壤較為黏重,小麥根系難以向下深扎,迫使小麥根系橫向生長,一定程度上彌補了總根長和總根面積。需進一步開展?jié)n害脅迫試驗,觀測小麥根系特征,以明確生物炭在漬害脅迫下對小麥根系的影響。
葉片是小麥進行光合作用的主要器官,漬害脅迫往往導(dǎo)致葉片氮含量和葉綠素含量下降,進而降低葉面積和葉片干物質(zhì)重[26]。生物炭含有較豐富的氮元素,施用生物炭將有利于小麥葉片生長。Olmo等[29]開展的小區(qū)試驗表明,施用生物炭可增加小麥葉片重量,在播種后187 d達到顯著水平。本研究中,施用生物炭的處理下,小麥葉齡和小麥葉片干重高于對照,但播種后90 d內(nèi)尚未達到顯著水平(數(shù)據(jù)未列出),而施用生物炭處理下小麥葉片SPAD值顯著高于對照(圖5)。進一步證實,生物炭對小麥葉片有積極作用,有助于提高葉片葉綠素含量,促進小麥前期的生長。施用生物炭處理下,小麥葉片的這些特點可能有助于提高小麥的耐漬能力,但同樣需要開展?jié)n害脅迫試驗進一步驗證。
稻麥輪作土壤中施用水稻秸稈生物炭,具有降低土壤容重、改善土壤排水條件等作用。同時,施用生物炭處理下的小麥具有苗壯根深的特點。生物炭對土壤物理性狀和小麥前期生長的影響,使得施用生物炭可成為抵御小麥漬害的潛在方法。后續(xù)研究將進一步觀測漬害脅迫下施用生物炭對小麥的生理過程和產(chǎn)量的影響,以定量評估生物炭在降低小麥漬害中的潛力。
[1] Li C,Jiang D,Wollenweber B,et al. Waterlogging pretreatment during vegetative growth improves tolerance to waterlogging after anthesis in wheat. Plant Science,2011,180(5):672—678
[2] Yao Z,Zheng X,Wang R,et al. Nitrous oxide and methane fluxes from a rice-wheat crop rotation under wheat residue incorporation and no-tillage practices.Atmospheric Environment,2013,79:641—649
[3] 姜東,陶勤南,張國平. 漬水對小麥揚麥5號旗葉和根系衰老的影響. 應(yīng)用生態(tài)學(xué)報,2002,13(11):1519—1521 Jiang D,Tao Q N,Zhang G P. Effect of waterlogging on senescence of flag leaf and root of wheat Yangmai 5(In Chinese). Chinese Journal of Applied Ecology,2002,13(11):1519—1521
[4] 石春林,金之慶. 基于 WCSODS的小麥漬害模型及其在災(zāi)害預(yù)警上的應(yīng)用. 應(yīng)用氣象學(xué)報,2003,14(4):462—468 Shi C L,Jin Z Q. A WCSODS-based model for simulating wet damage for winter wheat in the middle and lower reaches of the Yangtse River(In Chinese).Journal of Applied Meteorological Science,2003,14(4):462—468
[5] Jiang D,F(xiàn)an X,Dai T,et al. Nitrogen fertiliser rate and post-anthesis waterlogging effects on carbohydrate and nitrogen dynamics in wheat. Plant and Soil,2008,304(1/2):301—314
[6] Arguello M N,Mason R E,Roberts T L,et al.Performance of soft red winter wheat subjected to field soil waterlogging:Grain yield and yield components.Field Crops Research,2016,194:57—64
[7] 劉楊,石春林,宣守麗,等. 不同生育期漬水寡照對小麥產(chǎn)量構(gòu)成的影響. 江蘇農(nóng)業(yè)科學(xué),2016,44(10):124—127 Liu Y,Shi C L,Xuan S L,et al. Effect of waterlogging and shading at different stages on yield component of winter wheat(In Chinese). Jiangsu Agricultural Sciences,2016,44(10):124—127
[8] Rasaei A,Ghobadi M E,Jalali-Honarmand S,et al.Impacts of waterlogging on shoot apex development and recovery effects of nitrogen on grain yield of wheat.European Journal of Experimental Biology,2012,2(4):1000—1007
[9] 范雪梅,姜東,戴廷波,等. 花后干旱和漬水下氮素供應(yīng)對小麥旗葉衰老和粒重的影響. 土壤學(xué)報,2005,42(5):875—879 Fan X M,Jiang D,Dai T B,et al. Effects of nitrogen supply on flag leaf senescence and grain weight in wheat grown under drought or waterlogging from anthesis to maturity(In Chinese). Acta Pedologica Sinica,2005,42(5):875—879
[10] 朱建強,喬文軍,劉德福,等. 農(nóng)田排水面臨的形勢、任務(wù)及發(fā)展趨勢. 灌溉排水學(xué)報,2004,23(1):62—65 Zhu J Q,Qiao W J,Liu D F,et al. Situation and tasks of farmland drainage facing,and its tendency(In Chinese). Journal of Irrigation and Drainage,2004,23(1):62—65
[11] Zhao X,Zhou Y,Min J,et al. Nitrogen runoff dominates water nitrogen pollution from rice-wheat rotation in the Taihu Lake region of China. Agriculture,Ecosystems amp; Environment,2012,156:1—11
[12] 謝祖彬,劉琦,許燕萍,等. 生物炭研究進展及其研究方向. 土壤,2011,43(6):857—861 Xie Z B,Liu Q,Xu Y P,et al. Advances and perspectives of biochar research(In Chinese). Soils,2011,43(6):857—861
[13] Peake L R,Reid B J,Tang X. Quantifying the influence of biochar on the physical and hydrological properties of dissimilar soils. Geoderma,2014,235:182—190
[14] Verheijen F,Jeffery S,Bastos A. Biochar application to soils:A critical scientific review of effects on soil properties,processes and functions. Luxembourg:Office for the Official Publications of the European Communities,2010
[15] Mukherjee A,Zimmerman A R. Organic carbon and nutrient release from a range of laboratory-produced biochars and biochar–soil mixtures. Geoderma,2013,193:122—130
[16] Zhao X,Wang J,Wang S,et al. Successive straw biochar application as a strategy to sequester carbon and improve fertility:A pot experiment with two rice/wheat rotations in paddy soil. Plant and Soil,2014,378(1/2):279—294
[17] Feng Y,Sun H,Xue L,et al. Biochar applied at an appropriate rate can avoid increasing NH3volatilization dramatically in rice paddy soil. Chemosphere,2017,168:1277—1284
[18] Oguntunde P G,Abiodun B J,Ajayi A E,et al.Effects of charcoal production on soil physical properties in ghana. Journal of Plant Nutrition and Soil Science,2008,171(4):591—596
[19] 劉園,Khan M J,靳海洋,等. 秸稈生物炭對潮土作物產(chǎn)量和土壤性狀的影響. 土壤學(xué)報,2015,52(4):849—858 Liu Y,Khan M J,Jin H Y,et al. Effects of successive application of crop-straw biochar on crop yield and soil properties in cambosols(In Chinese). Acta Pedologica Sinica,2015,52(4):849—858
[20] Case S D C,McNamara N P,Reay D S,et al. The effect of biochar addition on N2O and CO2emissions from a sandy loam soil – The role of soil aeration. Soil Biology amp; Biochemistry,2012,51:125-134
[21] Jeffery S,Verheijen F G A,van der Velde M,et al. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis.Agriculture Ecosystems amp; Environment,2011,144(1):175—187
[22] 魯如坤. 土壤農(nóng)業(yè)化學(xué)分析方法. 北京:中國農(nóng)業(yè)科學(xué)技術(shù)出版社,2000 Lu R K. Analytical methods for soil and agro-chemistry(In Chinese). Beijing:China Agricultural Science and Technology Press,2000
[23] Aggarwal P K,Kalra N,Chander S,et al. Infocrop:A dynamic simulation model for the assessment of crop yields,losses due to pests,and environmental impact of agro-ecosystems in tropical environments. I. Model description. Agricultural Systems,2006,89(1):1—25
[24] Brassard P,Godbout S,Raghavan V. Soil biochar amendment as a climate change mitigation tool:Key parameters and mechanisms involved. Journal of Environmental Management,2016,181:484—497
[25] Gibbs J,Greenway H. Review:Mechanisms of anoxia tolerance in plants. I. Growth,survival and anaerobic catabolism. Functional Plant Biology,2003,30(1):1—47
[26] Malik A I,Colmer T D,Lambers H,et al. Shortterm waterlogging has long-term effects on the growth and physiology of wheat. New Phytologist,2002,153(2):225—236
[27] Gul S,Whalen J K. Biochemical cycling of nitrogen and phosphorus in biochar-amended soils. Soil Biology amp;Biochemistry,2016,103:1—15
[28] 張偉明,孟軍,王嘉宇,等. 生物炭對水稻根系形態(tài)與生理特性及產(chǎn)量的影響. 作物學(xué)報,2013,39(8):1445—1451 Zhang W M,Meng J,Wang J Y,et al. Effect of biochar on root morphological and physiological characteristics and yield in rice(In Chinese). Acta Agronomica Sinica,2013,39(8):1445—1451
[29] Olmo M,Alburquerque J A,Barrón V,et al. Wheat growth and yield responses to biochar addition under mediterranean climate conditions. Biology and Fertility of Soils,2014,50(8):1177—1187
(責(zé)任編輯:陳榮府)
Effect of Biochar Alleviating Waterlogging Stress of Winter Wheat in Rice-Wheat Rotation Systems
LIU Yang1,2LIU Xiaoyu2SHI Chunlin1?XUAN Shouli1SUN Bin1
(1 Institute of Agricultural Information/Key Laboratory of Agricultural Environment in Lower Reaches of the Yangtze River,MOA,Jiangsu Academy of Agricultural Sciences,Nanjing 210014,China)
(2 State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China)
【Objective】Crop rotation of rice and winter wheat is a common farming practice in areas of the middle and lower reaches of the Yangtze River. However,the paddy soils under such a cropping system are always heavy in texture,and tend to bring about waterlogging stress to the crop of winter wheat during its growing season under monsoon climate of winter wheat,thus inducing severe yield losses or loss of the whole crop. It is,therefore,essential to seek for a low cost and environment friendly method to alleviate yield losses caused by waterlogging stress for the sake of local food security. Biochar is an effective soil amendment and can be used to reduce soil hardening and enhance soil organic carbon sequestration. Nowadays,researches have has been carried out on application of biochar in areas under the crop rotation system in the middle and lower reaches of the Yangtze River. However,little has been reported on quantitative evaluation of the effect of biochar alleviating waterlogging stress of winter wheat in South China.【Method】Therefore,in the present study,soil column and plot experiments were conducted to investigate effects of application of biochar derived from rice straw in paddy fields under the rotation system on growth of winter wheat at its early stage,in an attempt to obtain a preliminary evaluation of the prospects of biochar application to alleviate waterlogging stress. Effects of biochar application varying in rate on soil bulk density and soil water content at different depths were evaluated through the soil column experiment,and its effects on wheat germination and wheat growth at early stage were through the plot experiment.【Result】Results show that biochar application significantly reduced bulk density of the soil. When biochar was applied at a rate of 10 and 40 t hm-2,soil bulk density was lowered by 7.4% and 11.4%,respectively,compared with CK(the treatment with no biochar applied). Dynamics of the soil in water content varied with soil depth. biochar application facilitated soil water percolation,thus alleviating the risk of waterlogging. Specifically,in the soil applied with biochar,soil water content at 20 cm in depth dropped rapidly after a simulated rainfall event compared with that in CK. The changes in physical properties of the soil applied with biochar indicated that drainage conditions of the soil were improved,favoring growth of winter wheat. In addition,compared with CK,biochar application at a rate of 10 t hm-2(BC)accelerated seed germination and promoted wheat growth at its early stage. Samples of winter wheat were collected on D90 after sowing for analysis of plant height,taproot length and chlorophyll relative content(SPAD value)of the new fully expanded leaf. It was found that they were all significantly higher in the treatments applied with biochar than in CK(p<0.05). The findings fully demonstrate that biochar application is beneficial to wheat growth at its early stage. However,its effects on dry matter weight of root,stem and leaf were not significant. In terms of characteristics of the root system,the plants in the biochar treatments had longer taproot than those did in CK,but did not differ much in total root length and total root area,which may be explained by the heavy texture of the soil CK. In such soils,the plant can not have its taproot go deep and for compensation have more lateral roots developed for water and nutrient absorption.【Conclusion】On the whole,biochar application can significantly improve drainage of the soil under crop rotation and benefit growth of the wheat at its early stage. All the findings listed above demonstrate that biochar application has the potential to alleviate waterlogging stress. However,further efforts should be made to study effects of biochar application on physiology and yield of winter wheat subjected to waterlogging so as to validate the hypothesis.
Rice-wheat rotation;Biochar;Waterlogging stress;Soil physical property;Soil column experiment
S156.3;S166
A
10.11766/trxb201705120210
* 國家公益性行業(yè)(農(nóng)業(yè))科研專項項目(201203032)、江蘇省農(nóng)業(yè)科學(xué)院院基金(6111647)和江蘇省農(nóng)業(yè)科技自主創(chuàng)新基金項目(CX(16)1042)資助 Supported by the Special Fund for Agro-scientific Research in the Public Interest(No.201203032),the Fund of Jiangsu Academy of Agricultural Sciences(No. 6111647),and the Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(No. CX(16)1042)
? 通訊作者 Corresponding author,E-mail:shicl@ jaas.ac.cn
劉 楊(1986—),男,江西宜春人,博士研究生,研究方向為氣候變化和土壤碳循環(huán)。E-mail:luisyang@126.com
2017-05-12;
2017-06-06;優(yōu)先數(shù)字出版日期(www.cnki.net):2017-06-27