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:高分辨率、栅格化的气候数据作为环境因子是地学模型和气候模型等相关研究的重要参数,国内外的研究多集中于温度、降水等气象要素,对陆面蒸发空间化研究较少。对黄土高原多沙粗沙区及周围共计53个气象站点(多沙粗沙区30个)蒸发皿测量值Epan进行空间插值,以5变量局部薄盘样条函数(经纬度为自变量。净辐射、水气压差和风速为协变量),建立具有多元线性子模型的蒸发插值模型,以ANUSPLIN为实现软件,生成连续21年共252个蒸发表面。交叉验证表明:引入蒸发影响因子作为协变量线性子模型进行表面插值能显著提高插值精度,夏季提高幅度更大,拟合表面具有较高的精确度与平滑度。蒸发随协变量的变率显示,在多沙粗沙区,水气压差是夏季蒸发的主要控制因素,风速对蒸发的影响冬季稍强一些,净辐射的影响没有明显的季节性,只在春分和秋分时节有微小提高。
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: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.