劉易,黃建,馬彥茹,祁通,馮耀祖,孟阿靜,王新勇
(新疆農(nóng)科院土壤肥料與農(nóng)業(yè)節(jié)水研究所,烏魯木齊 830091)
生物質(zhì)炭輸入對(duì)鹽化灰漠土壤水分運(yùn)移的影響
劉易,黃建,馬彥茹,祁通,馮耀祖,孟阿靜,王新勇
(新疆農(nóng)科院土壤肥料與農(nóng)業(yè)節(jié)水研究所,烏魯木齊 830091)
【目的】研究生物質(zhì)炭輸入對(duì)氯化物—硫酸鹽鹽化灰漠土水分垂直運(yùn)移的影響?!痉椒ā枯p、中、重鹽漬化土壤輸入不同量生物質(zhì)炭,以不添加生物質(zhì)炭為對(duì)照,通過(guò)滴加去離子水,觀測(cè)濕潤(rùn)鋒和累計(jì)入滲量隨入滲時(shí)間的變化?!窘Y(jié)果】各程度鹽漬化土壤不同生物質(zhì)炭輸入量處理,濕潤(rùn)鋒垂直運(yùn)移距離和累計(jì)入滲量隨入滲時(shí)間的持續(xù)均顯著增大(P﹤0.05);生物質(zhì)炭輸入阻礙水分在中、重度氯化物-硫酸鹽鹽化灰漠土入滲,低生物質(zhì)炭輸入量(≤4%)促進(jìn)水分在輕度鹽漬化土壤垂直運(yùn)移;輕、中度鹽化灰漠土輸入大量(≥6%)生物質(zhì)炭可增加累計(jì)入滲量,重度鹽化土壤累計(jì)入滲量隨生物質(zhì)輸入量增加而降低;不同生物質(zhì)炭輸入量處理間垂直濕潤(rùn)鋒深度的累積入滲量變化無(wú)規(guī)律?!窘Y(jié)論】生物質(zhì)炭輸入比例、鹽漬化程度及兩者的交互效應(yīng)對(duì)土壤水分的入滲效率和累計(jì)入滲量均有顯著影響:對(duì)中度鹽漬化土壤入滲速率和入滲量促進(jìn)作用突出;低量輸入對(duì)輕度鹽漬化土壤水分運(yùn)移有促進(jìn)作用;對(duì)重度鹽漬化土壤累計(jì)入滲量和入滲速率均有抑制作用。
生物質(zhì)炭;灰漠土鹽化土壤;水分
【研究意義】新疆是我國(guó)最重要的后備耕地資源省區(qū),由于其特殊氣候條件,水分蒸發(fā)強(qiáng)烈,土壤鹽分和地下水可溶性鹽分隨水向地表積聚,導(dǎo)致新疆土壤鹽漬化面積較大,達(dá)到8.476×106hm2[1],現(xiàn)有耕地中31.1%的面積受到鹽堿危害[2]。土壤鹽漬化是非鹽生植物重要的生長(zhǎng)限制因子,成為制約新疆農(nóng)業(yè)健康可持續(xù)發(fā)展的主要障礙,也是影響綠洲生態(tài)穩(wěn)定的重要因素。因此結(jié)合新疆鹽漬化土壤特性探尋其改良方法,防治和利用鹽漬化土壤已刻不容緩。【前人研究進(jìn)展】生物質(zhì)炭作為一種新型技術(shù)產(chǎn)品,快速增加土壤有機(jī)炭含量、改善土壤理化性質(zhì)、增加土壤持水性能[3],并能夠在相當(dāng)長(zhǎng)的時(shí)間內(nèi)保持粒狀結(jié)構(gòu),改善土壤結(jié)構(gòu)[4-5],近年來(lái)成為土壤學(xué)等領(lǐng)域研究的熱點(diǎn)。生物質(zhì)炭較大的比表面積、高度的孔隙結(jié)構(gòu)、有機(jī)質(zhì)的不同形態(tài)使生物質(zhì)炭具有較強(qiáng)的吸附性,能提高對(duì)土壤水分的吸附能力,增加土壤持水性能[6]。尤其是氧化后的生物質(zhì)炭可提高沙質(zhì)土壤的持水量,從而改善土壤持水能力[7]。【本研究切入點(diǎn)】“鹽隨水來(lái),鹽隨水去”,水的運(yùn)動(dòng)變化規(guī)律在鹽漬化危害和治理過(guò)程中起著主導(dǎo)和決定性的作用[8]。生物質(zhì)炭對(duì)土壤水分運(yùn)移的影響是對(duì)鹽分離子分布研究的前提,且不同鹽漬化土壤類(lèi)型和程度對(duì)生物質(zhì)炭的響應(yīng)不同。灰漠土是新疆典型的低產(chǎn)土壤之一,因此通過(guò)室內(nèi)模擬土柱試驗(yàn),建立不同程度灰漠土鹽漬化土壤水分運(yùn)移速度、入滲量與生物質(zhì)炭輸入水平相關(guān)性值得深入研究。【擬解決的關(guān)鍵問(wèn)題】通過(guò)生物質(zhì)炭輸入,研究其對(duì)新疆氯化物-硫酸鹽鹽化灰漠土壤水分運(yùn)移規(guī)律的影響,闡明其改良效益,為生物質(zhì)炭適用于鹽漬化土壤的改良利用提供理論依據(jù)。
1.1 材 料
1.1.1 供試土壤
供試土壤采自瑪納斯北五岔,土壤類(lèi)型為灰漠土,取土深度0~30 cm,經(jīng)碾壓、粉碎、風(fēng)干、過(guò)篩(2 mm),測(cè)定土壤基本理化性質(zhì)。重度鹽漬化耕地土壤含鹽量為16.3 g/kg;中度鹽漬化土壤含鹽量為10.2 g/kg;輕度鹽漬化土壤含鹽量為4.0 g/kg;依據(jù)Cl-/ SO42-離子毫克當(dāng)量比例在0.2~1為氯化物-硫酸鹽鹽漬化土壤的分類(lèi)方法[9],該供試土壤鹽漬化類(lèi)型為氯化物-硫酸鹽。表1
表1 供試土壤基本理化性質(zhì)
Table 1 Basic properties of the soil in the pot exeriment
處理TreatspH總鹽Totalsalt(g/kg)CO32-(g/kg)HCO3-(g/kg)Cl-(g/kg)SO42-(g/kg)Ca2+(g/kg)Mg2+(g/kg)K+(g/kg)Na+(g/kg)輕度Lowlevel7684000315046219001652000210350中度Mediumlevel7521020031507113518173100034240重度Highlevel74616300473109650081554014300463738
1.1.2 生物質(zhì)炭的制備
生物質(zhì)炭取自國(guó)家灰漠土土壤肥力與肥料效益檢測(cè)基地(N43°56′30〞,E87°28′16〞),原材料為棉花秸稈,溫度是500~700℃,燒制時(shí)間8 h,測(cè)定生物質(zhì)炭基本理化性質(zhì):pH 9.93,EC3.7 mS/cm,有機(jī)碳434.18 g/kg,全氮26.71 g/kg,全磷11.85 g/kg,全鉀22.54 g/kg,堿解氮5.83 mg/kg,速效磷200.49 mg/kg,速效鉀108.2 mg/kg,CEC12.65 cmol(+)/kk。
1.2 方 法
1.2 試驗(yàn)設(shè)計(jì)
供試土壤處理為輕、中、重3種程度鹽漬化土壤,根據(jù)自然土壤剖面層次和厚度,按照土壤容重為1.5 g/cm3,稱取所需土壤(<2 mm),依次從底層開(kāi)始裝填亞克力管土柱(厚度2 mm,高100 cm,內(nèi)徑8 cm),每次裝填厚度為10 cm,填裝高度為80 cm。生物質(zhì)炭輸入量按照質(zhì)量比分別為 0(BC0)、2%(BC2)、4%(BC4)、6%(BC6)、8%(BC8),將其換算為田間施入量分別為0、45、90、135和180 t/hm2。生物質(zhì)炭(<2 mm)與供試土壤混合均勻后裝填土柱,每個(gè)處理3次重復(fù)。土柱底部用亞克力板(10 cm×10 cm)密封,中間留直徑為2 mm孔,承接淋出液。為降低界面效應(yīng),在土層表面和底層裝入2 cm 厚的石英砂(<2 mm)。用醫(yī)用吊瓶向土柱滴加去離子水,保持約3 cm 的靜水頭,待濕潤(rùn)峰通過(guò)土壤表面2 cm石英砂時(shí)開(kāi)始計(jì)時(shí),連續(xù)記錄時(shí)間和相應(yīng)的入滲量,當(dāng)濕潤(rùn)鋒到達(dá)80 cm時(shí)停止供水。
1.3 數(shù)據(jù)統(tǒng)計(jì)
數(shù)據(jù)采用OriginPro 8.0和SPSS17.0進(jìn)行數(shù)據(jù)統(tǒng)計(jì)分析和顯著性檢驗(yàn)。
2.1 濕潤(rùn)鋒與入滲時(shí)間的關(guān)系
定水頭條件下積水入滲,土壤含水量剖面可分為飽和區(qū)、過(guò)渡區(qū)、傳導(dǎo)區(qū)和濕潤(rùn)區(qū),濕潤(rùn)區(qū)前端為濕潤(rùn)鋒,可表征水分在土壤基質(zhì)吸力和重力作用下的運(yùn)動(dòng)特征,即入滲中的垂直濕潤(rùn)鋒深度。研究表明輕度鹽漬化土壤輸入不同量生物質(zhì)炭,濕潤(rùn)鋒深度隨水分入滲時(shí)間延長(zhǎng)而增大。到達(dá)0~80 cm濕潤(rùn)鋒深度耗時(shí)差異顯著(P﹤0.05)。其中0~10 cm濕潤(rùn)鋒垂直深度耗時(shí):BC8﹥BC6﹥ BC4﹥ BC0﹥ BC2,差異不顯著(P﹥0.05);10~80 cm濕潤(rùn)鋒垂直深度耗時(shí):BC6﹥ BC8﹥ BC0﹥ BC2﹥ BC4,變化趨勢(shì)一致,差異顯著(P﹤0.05)。BC4水分運(yùn)移速度最快,80 cm僅耗時(shí)5 040 min。隨生物質(zhì)炭輸入量持續(xù)增加,水分入滲速度下降:BC6、 BC8處理濕潤(rùn)鋒運(yùn)移至80 cm處耗時(shí)分別為12 960、8 040 min。說(shuō)明生物質(zhì)炭輸入量過(guò)大會(huì)降低水分在輕度鹽漬化土壤中的運(yùn)移速度。圖1
圖1 生物質(zhì)炭輸入輕度鹽化灰漠土濕潤(rùn)鋒推進(jìn)曲線與入滲時(shí)間的關(guān)系
Fig.1 The relationship of wetting front invade curve with infiltration time in low level saliferous gray desert soil under the different input percentage of biomass carbon
研究表明,中度鹽漬化土壤輸入生物質(zhì)炭各處理水分到達(dá)濕潤(rùn)鋒耗時(shí):BC6﹥ BC8﹥ BC4﹥ BC2﹥ BC0,到達(dá)0~80 cm耗時(shí)一致。BC6處理到達(dá)80 cm濕潤(rùn)鋒深度耗時(shí)9 270 min,BC0僅2 820 min。說(shuō)明生物質(zhì)炭輸入阻礙水分在中度鹽漬化土壤中的運(yùn)移,BC6處理最顯著(P﹤0.05)。圖2
圖2 生物質(zhì)炭輸入中度鹽化灰漠土濕潤(rùn)鋒推進(jìn)曲線與入滲時(shí)間的關(guān)系
Fig.2 The relationship of wetting front invade curve with infiltration time in medium level saliferous gray desert soil under the different input percentage of biomass carbon
重度鹽漬化土壤輸入生物質(zhì)炭水分到達(dá)濕潤(rùn)鋒耗時(shí):BC8﹥ BC6﹥ BC2﹥ BC4﹥ BC0,到達(dá)0~80 cm耗時(shí)一致。BC8處理到達(dá)80 cm濕潤(rùn)鋒深度耗時(shí)7 680 min,BC0僅3 600 min。說(shuō)明生物質(zhì)炭輸入延緩水分在重度鹽漬化土壤中的運(yùn)移。
輸入生物質(zhì)炭,輕、中、重度鹽漬化土壤濕潤(rùn)鋒垂直運(yùn)移距離均隨入滲時(shí)間持續(xù)顯著增大(P﹤0.05)。但不同程度鹽漬化土壤間水分入滲時(shí)間和濕潤(rùn)鋒垂直深度有差異:0~10 cm濕潤(rùn)鋒垂直深度,中、輕度鹽漬化土壤BC0處理之間差異不顯著(P﹥0.05),與重度鹽漬化土壤BC0差異顯著(P﹤0.05),重度鹽漬化土壤到達(dá)10 cm濕潤(rùn)鋒耗時(shí)120 min,說(shuō)明重度鹽漬化土壤團(tuán)粒結(jié)構(gòu)差于輕、中度,大粒徑顆粒含量低。輕、中度鹽漬化土壤BC8處理耗時(shí)最長(zhǎng),重度鹽漬化土壤BC6處理耗時(shí)最長(zhǎng),達(dá)140 min。隨入滲水量的持續(xù)增加,重力勢(shì)促使水分垂直向下運(yùn)動(dòng),水分到達(dá)不同程度鹽漬化土壤10~80 cm濕潤(rùn)鋒垂直深度耗時(shí)差異顯著(P﹤0.05),總體表現(xiàn)為:輕度﹥重度﹥中度;輕度、中度鹽漬化土壤BC6和重度鹽漬化土壤BC8處理水分運(yùn)移到達(dá)80 cm濕潤(rùn)鋒垂直深度耗時(shí)最長(zhǎng),分別是12 960、9 270和7 680 min,較輕、中、重度鹽漬化土壤BC0慢125%、229%和113%。圖3
圖3 生物質(zhì)炭輸入重度鹽化灰漠土濕潤(rùn)鋒推進(jìn)曲線與入滲時(shí)間的關(guān)系
Fig.3 The relationship of wetting front invade curve with infiltration time in high level saliferous gray desert soil under the different input percentage of biomass carbon
采用冪函數(shù)對(duì)水分在生物質(zhì)炭輸入鹽漬化土壤后的垂直運(yùn)移距離與入滲時(shí)間進(jìn)行擬合:
H=aTb.
式中:H為為濕潤(rùn)鋒運(yùn)移距離(cm),T為入滲時(shí)間(min),b為入滲指數(shù),a為入滲系數(shù)。
生物質(zhì)炭輸入鹽漬化土壤后,水分到達(dá)濕潤(rùn)鋒垂直深度與入滲時(shí)間擬合結(jié)果為,R2為相關(guān)系數(shù)。輕度鹽漬化處理中,生物質(zhì)炭輸入量≤6%,b隨生物質(zhì)炭輸入量的增大而增加,輸入量繼續(xù)增大時(shí),b降低,BC8降至0.46,a變化與生物質(zhì)炭輸入量無(wú)規(guī)律;中度鹽漬化處理,生物質(zhì)炭輸入量≤6%,b隨著生物質(zhì)炭輸入量的增大而減少,a無(wú)明顯變化規(guī)律;重度鹽漬化處理,a、b均無(wú)明顯變化規(guī)律。鹽漬化土壤輸入生物質(zhì)炭后擬合相關(guān)系數(shù)均在0.99以上,說(shuō)明生物質(zhì)炭輸入鹽化灰漠土,濕潤(rùn)鋒推進(jìn)距離和入滲歷時(shí)均存在較好的冪函數(shù)關(guān)系。表2
表2 生物質(zhì)炭輸入鹽化灰漠土壤H-t擬合結(jié)果
Table 2H-tcorelationship of saliferous gray desert soil under the different input percentage of biomass carbon
鹽漬化程度Saliferouslevel擬合關(guān)系Corelationship生物質(zhì)炭輸入量Inputpercentageofbiomasscarbon02%4%6%8%輕度Lowsaliferousb047±0096049±0092049±0025050±0092045±0051a124±0247109±0181120±0107082±0066111±0126R2099±0095099±009099±0098099±0095099±0010中度Mediumsaliferousb057±0001055±0023051±0035050±0006052±0047a087±0098079±0071107±0048081±0064080±0039R2099±0084099±0096099±0092099±0050099±0083重度Highsaliferousb060±0012047±0019051±0053054±0011052±0035a058±0030126±0064106±0008069±0088073±0067R2099±0099099±0094099±0096099±0098099±0094
2.2 累積入滲量與入滲時(shí)間的關(guān)系
累計(jì)入滲量是入滲開(kāi)始后一段時(shí)間內(nèi),通過(guò)地表單位面積入滲到土壤中的總水量。鹽漬化土壤輸入不同量生物質(zhì)炭的累積入滲量隨時(shí)間的變化為:輕、中、重鹽漬化土壤輸入生物質(zhì)炭,累積入滲量均隨時(shí)間延長(zhǎng)顯著增大(P﹤0.05)。入滲初期,三種程度鹽漬化土壤輸入生物質(zhì)炭各處理入滲速率均較大,累計(jì)入滲曲線較陡,其中輕度BC0、中度BC4、重度BC4入滲速率分別為5.07、5.47和4.31 mL/min。隨入滲時(shí)間持續(xù),入滲速率均顯著降低(P﹤0.05)。入滲結(jié)束,輕度鹽漬化土壤入滲速率:BC2﹥ BC4﹥ BC0﹥ BC8﹥ BC6,BC6入滲速率0.12 mL/min,較BC0低60.61%;中度鹽漬化土壤入滲速率BC0﹥ BC2﹥ BC4﹥ BC8﹥ BC6,BC6入滲速率0.20 mL/min,較BC0低66.10%;重度鹽漬化土壤入滲速率BC0﹥ BC4﹥ BC2﹥ BC6﹥ BC8,BC8入滲速率0.21 mL/min,較BC0低54.15%;不同程度鹽漬化土壤入滲速率:中度﹥ 輕度﹥重度。圖4~6
圖4 生物質(zhì)炭輸入輕度鹽化灰漠土累積入滲量與入滲時(shí)間的關(guān)系
Fig.4 The relationship of accumulate infiltration capacity with infiltration time in low saliferous gray desert soil under the different input percentage of biomass carbon
為定量分析生物質(zhì)炭輸入累積入滲量與入滲時(shí)間關(guān)系,采用模型對(duì)數(shù)據(jù)進(jìn)行擬合,即
I=KTa.
式中:I為累積入滲量(mL),T為入滲時(shí)間(min),a為入滲指數(shù),K為入滲系數(shù)。
生物質(zhì)炭輸入鹽漬化土壤入滲量與入滲時(shí)間擬合結(jié)果為,R2為相關(guān)系數(shù)。輕、中、重度鹽漬化土壤各生物質(zhì)炭輸入量處理,a、K無(wú)明顯變化規(guī)律。其中輕度鹽漬化BC8處理a降至0.358。擬合相關(guān)系數(shù)除BC2外,均在0.99以上;中度、重度鹽漬化土壤BC4處理,a均最低,擬合相關(guān)系數(shù)除中度鹽漬化土壤BC6處理外,均在0.99以上。擬合結(jié)果表明生物質(zhì)炭輸入不同程度鹽化灰漠土,累積入滲量和入滲歷時(shí)均存在較好的冪函數(shù)關(guān)系。但不同程度鹽漬化土壤處理和生物質(zhì)炭處理間變化無(wú)規(guī)律。表3
圖5 生物質(zhì)炭輸入中度鹽化灰漠土累積入滲量與入滲時(shí)間的關(guān)系
Fig.5 The relationship of accumulate infiltration capacity with infiltration time in medium saliferous gray desert soil under the different input percentage of biomass carbon
圖6 生物質(zhì)炭輸入重度鹽化灰漠土累積入滲量與入滲時(shí)間的關(guān)系
Fig.6 The relationship of accumulate infiltration capacity with infiltration time in high saliferous gray desert soil under the different input percentage of biomass carbon
表3 室內(nèi)試驗(yàn)生物質(zhì)炭輸入鹽化灰漠土K-a擬合結(jié)果
Table 3K-acorelationship of saliferous gray desert soil under the different input percentage of biomass carbon in the lab
鹽漬化程度Saliferouslevel擬合關(guān)系Corelationship生物質(zhì)炭輸入量Inputpercentageofbiomasscarbon02%4%6%8%輕度LowlevelK4530±10933499±10584530±09313375±12615394±1725a041±00078044±00059041±00080043±00026035±00075R2099±00065097±00034099±00066099±00074099±00048中度MediumlevelK3544±1692769±1044841±1711873±0853280±122a048±00039049±00091041±00090050±00013044±00089R2099±00074099±00019099±00037097±00055099±00059重度HighlevelK3045±1545955±2625208±1633513±1633148±122a048±00067039±00032038±00052044±00024043±00086R2099±00068099±00042099±00039099±00055099±00045
2.3 累積入滲量與濕潤(rùn)鋒之間的關(guān)系
輕、中、重度鹽漬化土壤輸入生物質(zhì)炭,累積入滲量隨濕潤(rùn)鋒垂直深度的增加顯著增大(P﹤0.05)。生物質(zhì)炭輸入量小于4%,降低輕度鹽漬化土壤水分累計(jì)入滲量,生物質(zhì)炭輸入量大于6%,促進(jìn)水分累計(jì)入滲。0~80 cm累計(jì)入滲量變化趨勢(shì)一致:BC6>BC8>BC0>BC2>BC4,差異不顯著(P>0.05)。圖7
圖7 生物質(zhì)炭輸入輕度鹽化灰漠土累積入滲量與濕潤(rùn)鋒垂直深度的關(guān)系
Fig.7 The relationship of accumulate infiltrationcapacity with wetting front invade curve in low saliferous gray desert soil under the different input percentage of biomass carbon
中度鹽漬化土壤水分累計(jì)入滲量隨生物質(zhì)炭輸入量增加逐漸增大,BC6處理累計(jì)入滲量達(dá)1 890 mL,0~80 cm累計(jì)入滲量變化趨勢(shì)一致:BC6>BC8>BC2>BC0>BC4,差異不顯著(P>0.05)。說(shuō)明生物質(zhì)炭促進(jìn)中度鹽漬化土壤水分累積,但生物質(zhì)量大于6%抑制水分累積。圖8
圖8 生物質(zhì)炭輸入中度鹽化灰漠土累積入滲量與濕潤(rùn)鋒垂直深度的關(guān)系
Fig.8 The relationship of accumulate infiltrationcapacity with wetting front invade curve in medium saliferous gray desert soil under the different input percentage of biomass carbon
重度鹽漬化土壤水分累計(jì)入滲量隨生物質(zhì)炭輸入量增加逐漸減少,BC0處理累計(jì)入滲量最大,達(dá)1 785 mL;0~80 cm累計(jì)入滲量變化趨勢(shì)一致:BC0>BC2>BC8>BC6>BC4,差異不顯著(P>0.05)。表明生物質(zhì)炭輸入抑制重度鹽漬化土壤水分累積入滲。圖9
圖9 生物質(zhì)炭輸入重度鹽化灰漠土累積入滲量與濕潤(rùn)鋒垂直深度的關(guān)系
Fig.9 The relationship of accumulate infiltrationcapacity with wetting front invade curve in high saliferous gray desert soil under the different input percentage of biomass carbon
用線性函數(shù)I=C×H,擬合濕潤(rùn)鋒和累積入滲量的實(shí)測(cè)資料,式中符號(hào)意義同前,其中I為累積入滲量(mL);H為為濕潤(rùn)鋒運(yùn)移距離(cm);C為擬合系數(shù);R2為相關(guān)系數(shù)。
擬合直線如下:
輕度鹽漬化土壤:Y=20.833 33X,
R2=0.997 26.
中度鹽漬化土壤:Y=21.251 47X,
R2=0.997 07.
重度鹽漬化土壤:Y=21.598 04X,
R2=0.995 41.
由擬合結(jié)果可知,生物質(zhì)炭輸入輕、中、重度鹽化灰漠土累積入滲量與濕潤(rùn)鋒距離相關(guān)系數(shù)均大于0.99,表現(xiàn)出較好的線性關(guān)系。
土壤入滲特征與土壤質(zhì)地、容重、含水率、水穩(wěn)性團(tuán)粒含量等多種因素相關(guān)[10]。其中土壤孔隙狀況對(duì)土壤水分的入滲過(guò)程、持水容量和動(dòng)力學(xué)特征影響尤為突出。試驗(yàn)供試灰漠土呈棕黃色,質(zhì)地為砂壤;土壤大孔隙和水分傳導(dǎo)孔隙大,孔隙彎曲程度低,致使土壤水分傳導(dǎo)性強(qiáng),但保水性能弱。入滲初始,供試土壤干燥,基質(zhì)勢(shì)較大,不同程度鹽漬化土壤水分入滲速率均較大。隨入滲時(shí)間持續(xù),表層土壤含水量逐漸增加,基質(zhì)勢(shì)減小,入滲速率逐漸降低,與齊瑞鵬等[11]研究結(jié)果一致。
生物質(zhì)炭多孔結(jié)構(gòu)和巨大表面積等特性可改善土壤持水能力[12-15],影響土壤水分的滲濾模式、停留時(shí)間和流動(dòng)路徑[16-17]。齊瑞鵬等[11]研究表明,施加生物炭對(duì)質(zhì)地較黏的土壤(塿土)水分入滲有增加作用,對(duì)質(zhì)地輕的土壤(風(fēng)沙土)水分入滲則有減小作用。研究生物質(zhì)炭持水性能高于供試土壤顆粒,大量輸入(≥6%)改變鹽化灰漠土的入滲性能,入滲速率降低;低生物質(zhì)炭輸入量(≤4%)促進(jìn)了水分入滲速率,這與生物質(zhì)炭自身赤水能力有關(guān)[18],與Brodowski等[19]研究結(jié)論相符。
供試生物質(zhì)炭粒徑小于供試土壤,輸入后破壞了土壤原有結(jié)構(gòu),改變土壤孔隙大小分布,減小灰漠土的透水大孔隙數(shù)量,提高土壤微小孔隙比例,增強(qiáng)土壤持水性能,導(dǎo)致輕、中度鹽漬化土壤中生物質(zhì)炭輸入量大于6%,累積入滲量增加。不同燒制材料、炭化溫度和時(shí)間對(duì)生物質(zhì)炭pH值、電導(dǎo)率和陽(yáng)離子交換性均有影響[20-22],進(jìn)而改變土壤結(jié)構(gòu)特征,影響水分運(yùn)移。研究用生物質(zhì)炭為棉稈燒制,鹽分含量高(pH 9.93、總鹽22.4),重度鹽漬化土壤含鹽量隨生物質(zhì)炭輸入量增加而提高,鹽分離子聚集,鈉離子對(duì)土壤顆粒的分散作用使得土壤結(jié)構(gòu)遭到破壞,水分在土壤中的入滲能力降低,導(dǎo)致累計(jì)入滲量隨生物質(zhì)炭輸入量增加而降低。
因自然界、人為干預(yù)等因素影響,土體并非均勻,鹽漬化土壤表層與下層的土壤質(zhì)地不一。試驗(yàn)通過(guò)土柱模擬0~80 cm土層土壤,其理化性質(zhì)均勻一致。因此該數(shù)據(jù)不代表自然土體的水分運(yùn)移,需做進(jìn)一步細(xì)致研究分析。
輕、中、重度鹽化土壤輸入不同生物質(zhì)炭量,濕潤(rùn)鋒垂直運(yùn)移距離和累積入滲量隨入滲時(shí)間持續(xù)顯著增大(P﹤0.05);累積入滲量隨濕潤(rùn)鋒垂直深度的增加顯著增大(P﹤0.05)。生物質(zhì)炭輸入量小于4%促進(jìn)水分在輕度鹽化灰漠土中的垂直運(yùn)移;輸入生物質(zhì)炭阻礙水分在中、重度鹽化灰漠土垂直運(yùn)移;輕、中度鹽化灰漠土輸入生物質(zhì)炭量大于6%,累積入滲量隨炭輸入量增大而減少,BC0累積入滲量最大;重度鹽化土壤累計(jì)入滲量隨生物質(zhì)炭輸入量增加而降低。
生物質(zhì)炭輸入量對(duì)輕、中、重度鹽化土壤累計(jì)入滲量和垂直濕潤(rùn)鋒深度影響無(wú)規(guī)律;相同濕潤(rùn)鋒垂直深度,不同程度鹽化土壤間累計(jì)入滲量差異不顯著(P>0.05)。
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Supported by:NFSC "Effects induced by inputting biochar into the saliferous gray desert soil on the soil moisture movement and its biological response" (41361050), NFSC "Desalination zone formation mechanism and regulation of cotton in heavily salinized soil under drip irrigation" (41461409) and the Youth Funds of Xinjiang Academy of Agricultural Sciences "Effects induced by inputting biochar into the saliferous gray desert soil on the soil moisture movement" (xjnky-2013012)
Effects Induced by Inputting Biochar into the Saliferous Gray Desert Soil on the Soil Moisture Movement
LIU Yi, HUANG Jian, MA Yan-ru, QI Tong, FENG Yao-zu, MENG A-jin, WANG Xin-yong
(ResearchInstituteofSoil,FertilizerandAgriculturalWaterConservation,XinjiangAcademyofAgriculturalSciences,Urumqi830091,China)
【Objective】 To study the effect of biomass carbon input on soil moisture vertical movement in chloride-sulfate saliferous gray desert soil.【Method】The study materials were gray desert soil in three salinization levels which level 1 was low salinization, level 2 was medium salinization and level 3 was high salinization. Under different percentages of biochar inputs before and through the dropwise add of ddH2O, the time-varying of wetting front and accumulative infiltration capacity were calculated and analyzed.【Result】The vertical migration distance and the cumulative infiltration rate of wetting front were significantly increased (P< 0.05) with the infiltration time of different biomass carbon inputs in each degree of saline soil. The soil moisture movement in level 2 and level 3 saliferous soil were hindered by the biomass carbon; when the input percentage of biomass carbon was less than 4% to level 1 saliferous soil, the soil moisture movement could be facilitated by the biomass carbon; The relationship of biomass carbon input percentage with accumulative infiltration capacity in these three salinization soil were negatively correlated; there was no found in the relationship of biomass carbon inputs percentage with the accumulative infiltration capacity of vertical depth of wetting front in different salinization soil.【Conclusion】The ratio of biomass carbon input, the degree of salinization and the interaction effect of the two have a significant impact on the infiltration efficiency and cumulative infiltration of soil water. The infiltration rate and infiltration amount to moderately saline soil were prominent. Low level input has a promoting effect on water transport in mildly saline soil and inhibitory effect on both cumulative infiltration rate and infiltration rate in severe saline soil.
biochar; saliferous gray desert soil; soil moisture
10.6048/j.issn.1001-4330.2017.02.018
2016-06-26
國(guó)家自然科學(xué)基金項(xiàng)目“生物質(zhì)炭輸入對(duì)新疆鹽漬化土壤水鹽運(yùn)移的影響及生物學(xué)響應(yīng)”(41361050);國(guó)家自然科學(xué)基金項(xiàng)目“滴灌條件下重鹽漬化棉田土壤鹽分淡化區(qū)形成機(jī)制及調(diào)控”(41461049);新疆農(nóng)科院優(yōu)秀青年科技人才基金項(xiàng)目“生物質(zhì)炭輸入對(duì)新疆鹽漬化土壤水鹽運(yùn)移的影響”(xjnky-2013012)
劉易(1983-),男,河北保定人,助理研究員,碩士,研究方向?yàn)辂}漬化土壤改良與修復(fù),(E-mail)liuyun_5511@163.com
王新勇(1961-),男,浙江江山人,研究員,研究方向?yàn)辂}漬化土壤治理與防治,(E-mail)wxy838000@163.com
S153
A
1001-4330(2017)02-0343-09