简介:岩溶石漠化是广西脆弱生态恢复建设中面临的突出生态环境问题.以1988、1998和2008年3个时相的TM/ETM卫星数据为主要信息源,综合碳酸盐空间分布图、石漠化状况实地调查结果和历史资料,基于3S技术,构建岩溶石漠化遥感监测和分级评价模型,研究广西平果县岩溶区石漠化空间分布特征及演变规律.结果表明:1)岩溶石漠化遥感监测和分级评价模型能够反映平果县石漠化状况,基本符合实地调查结果;2)平果县岩溶石漠化主要分布在该县西南部和中部,1988-2008年,平果县总体石漠化程度经历了稍加重然后逐渐变轻的变化趋势,石漠化呈现动态、缓慢、反复、可治理等特点.建议采取先易后难、逐步改善的治理策略.研究结果可为中国西南岩溶石漠化治理和区域生态建设的宏观决策提供参考.
简介:Sulfurtransformationin3soilsmaintainedinaclosedincubationsystemanditsavailabilitytoplantswereinvestigatedusingcarrier-free^35S-SO4^2-and^35S-labeledryegrassstraw.Forcarrier-freeNa2^35SO4treatment,78%,70%and64%of^35SappliedwerefoundinCa(H2PO4)2-extractaleSfraction,4%,5%and7%inslowlysolubleinorganicS,11%,15%and18%inC-O-S,5%,7%,and6%inC-bondedS,and5%,7%and6%inunidentifiedorganicS120daysafterincubationinblacksoil,cinnamonsoilandchestnutsoil,respectively.Mostof35Suptakebyplantscamefromextractable35SO4^2-,andlittlefromC-O-^35SandC-bonded^35S,Inthetreatmentwith35S-labeledstraw,51%,46%and36%of35SincorporatedwerefoundinCa(H2PO4)2-extractableSfraction,7%,6%and7%inslowlysolubleinorganicS,13%,15%and18%inC-O-S,8%,8%and6%inC-bondedS,and18%,25%and35%inunidentifiedorganicSattheendofincubationinabove-mentonedthreesoils,respectively.HigheravailabilityofC-O-35S,C-bonded35Sandunidentifiedorganic35Sfrom35S-labeledstrawwasobservedin35S-labeledstrawtreatmentcomparedtocarrier-freeNa2^35SO4treatment.
简介:在低丘红壤的开发利用中,通过复合农林业技术达到植树种草、增加地面覆盖率、发展当地经济植物促进畜牧业发展,探索低丘红壤开发利用的新模式,科学舍理地开发红壤资源,实现开发中保护。经过2年的试验表明:选择适宜的植物种类对于有效地发挥生物措施与复合农林技术的功效是极其重要的,各试验块的植被覆盖度分别是湿地松18%,茶叶23%,柑橘34.6%;覆盖度大小顺序依次为柑橘〉茶叶〉湿地松;低丘红壤开发的第1年土壤侵蚀量一般都超过土壤允许侵蚀量500t/km^2.a,第2年就减小到350t/km^2.a左右,各类型的土壤平均侵蚀量次序为柑橘〉湿地松〉茶叶;各处理的平均N素流失量为湿地松138.8kg/km^2,茶叶450.1kg/km^2,柑橘182.4kg/km^2;N素流失大小顺序为茶叶〉柑柑橘〉湿地松。在试验区采样分析结果表明:随着土壤侵蚀的逐步升级,土壤容重、田间持水量、土壤粉粒、土壤团聚体、土壤pH、土壤盐基饱和度、土壤盐基交换量均相应降低,而土壤交换性酸对应增加。验证了水土流失直接导致土壤结构、土壤物理性状退化、变差的结果。
简介:FieldlysimetermethodwasemployedtoinvestigatethedownwardmovementandleachingofNappliedtosummercorn(ZeamayL.)ondrylandsoilinBeijing,AN-fertilizer(120kgNhm^-2)andacontroltreatmentwerarrangedforthestudy.Soilsolutionwascollectedatdepthsof20,40,60,120and170cm,whileleachtewasollectedatthebottom(220cm)ofthelysimeter,TheresultsshowedthatthedownwardmovementofNO3^-Ninsoilprofilewasgreatlyaffectedbyrainfallpattern.ThepeakofleachedNO3^-Nfrombothtreatmentscoincidedwiththepeakoftherainfall.Inaddition,leachedNO3^-Nfrombothtreatmentsandrainfallweresignificantlycorrelated(P<0.05).TheamountofleachedNO3^-NwasnotgreatintheN-fertilizertreatment,TheresultsalsosuggestedthatNfertilizationcouldcauseNO3^--Ncontaminationofgroundeaterduringtherainyseason.
简介:EctomycorrhizalfungusLaccariabicolorS238N,isolatedfromaforestsoilincentralFrancein1990s,hasdemonstratedunequivocallyandabilitytopromotepinegrowth.Inthepresentnurserybedexperiment,theabilityofthisectomycorrhizalfungustoincreasegrowthandPandKuptakeofDouglasFirseedlings(Zone22)wasexamined.Growthofinoculatedseedlingswasovertwice(plantheight)andthreetimes(biomass)thatofnon-inoculatedones.Similarly,boththeconcentrationsandtheamountsofPandKuptakebyseedlingsweresignificantlyincreasedbyfungalinoculation,indicatingtheimprovementofPandKnutritioninmycorrhizalseedlings.Incontrast,Al-Pinthesoilswasdecreasedobviouslybyplants,especiallybymycorrhizas,suggestingutilizationofthissoilPpoolbyplantsandmoreefficientAl-Pmobilizationbymycorrhizasthanbynomycorrhizas.Moreover,Kextractedby1mol/LHClfollowingconsecutiveextractionofH2OandCH3COONH4,whichmaynotbeplantavailable,couldbeutilizedbyfunguscoloniedroots.ThiscouldbeexplainedbythereleaseofprotonsandoxalatebyhypaewhichleadstoreplacementofinterlayerKinnonexpanded2:1claymineralsandbio-weatheringofphyllosilicates.
简介:Soiltestforavailabilityofnutrientsandheavymetalsisextensivelyservedasameansfortheevaluationsofsoilfertility,andenvironmentaleffectsandphytotoxicityofpollutantsinsoils,andforthefertilizerrecommendationinagriculturalandenvironmentalsciences.Therefore,greatattentionhasbeenpaidtothemeasurementofelementalavailabilityinsoiltest.
简介:心土酸味限制根生长并且在世界的许多部分减少庄稼收益。多于氮(N)在庄稼生产使用了的化肥的一半是当前输了到环境。这研究试图在到没有为止玉米(ZeamaysL.)在N化肥的效率上调查石膏申请的效果在南部的巴西的生产。一个地实验检验了适用表面的石膏的效果(0,5,10,和15Mg哈1)和穿衣顶的铵硝酸盐(NH4没有3)(60,120,和180kgN哈玉米根长度,N举起,和谷物产量上的1)。一个温室实验用从地实验地点收集不评估3-N与适用表面的石膏沥滤,N举起,和根长度的没受到干扰的土壤列被进行(0和10Mg哈1)和穿衣顶的NH4没有3(0和180kgN哈1)。心土酸味的改善由于石膏申请,增加的玉米根生长,N举起,谷物收益,和N使用效率。到土壤表面的适用的石膏由19%-38%和N的部分因素生产率增加了玉米谷物产量(PFP由27%-38%的N),取决于N申请率。没受到干扰的土壤列温室实验的结果证明由石膏申请的N使用效率的那改进由于从在由于增加的玉米根长度的心土的没有3-N的更高的N举起。我们的结果建议有在一个到没有为止玉米系统的石膏的那改善心土酸味能增加N使用效率,改进谷物产量,并且减少由于沥滤的没有3-N的环境风险。