简介：Thenaturalsupplyoflandresourcesislimited,buttheeconomicsupplymaychangealongwithsocialandeconomicdevelopment,anditssizeisdecidedbyenatureandsocialandeconomicbodyconditions.Whenthesupplyingabilityoflandresourcesthreatensthedevelopmentofsocietyandtheconflictbetweenpeopleandlandbecomestense,itforcedpeopletoim-provelandutilizationandtoincreasetheeffectivesupplyoflandresources.ThepapermadeanoverallconsiderationonthecharacteristicsoftheirrigatedfarmingandthefrailecologicalenvironmentinFuhaiCounty,AltayArea,XinjiangUigurAutonomousRegionandexploredlandarrangementplanningaswellaswaterresourceplanningandenvironmentalprotection.Thepaperevaluatednaturalresources,landutilizationandwaterresourceofthecasestudyareasandfocusedonthespatio-temporalbalancebetweentheutilizationofwaterandlandresources.Intheendthepaperafeasibleplanwasmadeoutforthelandarrangementproject.

简介：Themethaneconcentrationprofilefrom-1.5mdepthinsoilto32mheightinairwasmeasuredinalpinesteppelo-catedinthepermafrostarea.Methaneconcentrationsshowedwidelyvariationsbothinairandinsoilduringthestudyperiod.Themeanconcentrationsinatmospherewereallhigherthanthoseinsoil,andthehighestmethaneconcentrationwasfoundinairattheheightof16mwiththelowestconcentrationoccur-ringatthedepthof1.5minsoil.Thevariationsofatmosphericmethaneconcentrationsdidnotshowanyclearpatternbothtemporallyandspatially,althoughtheyexhibitedamoresteady-stablestatethanthoseinsoil.Duringtheseasonalvariations,themethaneconcentrationsatdifferentdepthsinsoilweresig-nificantlycorrelated(R2>0.6)witheachothercomparingtotheweakcorrelations(R2<0.2)betweentheatmosphericconcentra-tionsatdifferentheights.Meanmethaneconcentrationsinsoilsignificantlydecreasedwithdepth.Thiswasthecompositiveinfluenceofthedecreasingproductionratesandtheincreasingmethaneoxidationrates,whichwascausedbythedescentsoilmoisturewithdepth.Althoughthemethaneconcentrationsatalldepthsvariedwidelyduringthegrowingseason,theyshowedverydistincttemporalvariationsinthenon-growingseason.Itwasindicatedfromtheliteraturesthatmethaneoxidationrateswerepositivelycorrelatedwithsoiltemperature.Thehighermethaneconcentrationsinsoilduringthewinterweredeter-minedbythelowermethaneoxidationrateswithdecreasingsoiltemperatures,whereasmethaneproductionrateshadnoreactiontothelowertemperature.Relationsbetweenmethanecontributionandotherenvironmentalfactorswerenotdiscussedinthispaperforlackingofdata,whichimpulseustocarryoutfurtherandmoredetailedstudiesinthisuniquearea.

简介：SoutheastChinaisoneoftheseveresoildegradationareasinChina.Thispapertheoreticallyexaminestheimpactofsomeimportantinstitutionalarrangementsandpolicies,likelandmanagementpattern,theruraloff-farmemployment,landpropertychangeandchangesinpricesofagriculturalproducts,onsoildegradationinthisarea.Itfurtherconductssomecasestudiestoconfirmthepotentialrelationshipbetweentheinstitutions&policiesandsoildegradation,applyingthesurveyedandthesecondhanddata.Thepaperatlastmakessomeconclusionsandproposessomesuggestionsonhowtopromotesoilconservationbyimprovingthewaysofpolicydecision-makingandtheeffectsofpoliciesonlanduse.

简介：PermafrostdegradationisprevalentontheQinghai-TibetPlateau.Thismayleadtochangesinwaterandheattransitioninsoilsandthusaffectthestructureandfunctionofecosystems.Inthispaper,usingthemeasureddataofalpinesteppeinWudaoliangassessedthemodelperformanceinsimulatingsoilfreezingandthawingprocesses.Comparisonofthesimulatedresultsbysimultaneousheatandwater(SHAW)modeltothemeasureddatashowedthatSHAWmodelperformedsatisfactorily.Basedonanalyzingthesimulatedandpredictedresults,twopointswereobtained:(1)freezingandthawingoftheactivelayerproceededbothfromthesoilsurfacedownward.Comparedwiththefreezingprocess,thethawingprocesswasslower.Thefreezingperiodpersistedinthesurfacelayer(4cmdepth)forabout5months;(2)inthenext50years,frozenperiodwouldbeshortenabout20daysinthetop100cmdepthwhilethethawingwouldstartearlier40daysthanpresent.Soilwaterstorageinthe0-60cmwoulddecreaseby22%averagely,especiallyfromJunetoAugustwhenthevegetationisatthedominatingwaterconsumedstage.Therefore,thiskindofpermafrostdegradationasactivelayerfreezingandthawingprocesseschangeswillreducesoilwatercontentandthusinfluencethoseecosystemsaboveit.

简介：Theobjectiveofthisstudywastoinvestigatetheef-fectsofearthwormdensityontheavailabilityofnutrientsandheavymetalsinmetalcontaminatedsoils.Pb/Znminetailingsweremixedthroughlywitharedyellowpodzolicsoilattheratio(w/w)of75:25.Earthworms(Pheretimasp.)wereintroducedtothemixtureatfourdifferentdensities,zero,three,sixandnineindividualsperpotplantedwithryegrass(Loliunmultiflorum).Theresultsindicatedthatearthwormactivitysignificantlyen-hancedryegrassshootbiomass.However,asdenserearthwormpopulationwasintroduced,shootbiomasstendedtodecrease.EarthwormactivitysignificantlyincreasedsoilpHandavailabilityofN,PandKinthetailingsandsoilmixture.TherewasageneraltendencythatuptakeofZnbyryegrassincreasedafterearthworminoculation,althoughtheincreaseinextractableZnintailingsandsoilmixturewasnotsignificant.Onthecontrary,thereseemedtobealoweruptakeofPbbyryegrassunderearthworminoclation,despitethefactthathigherextractablePbconcentrationswereobserved.Thepresentprojectindicatedthattheimprovedgrowthofryegrasswasduetoimprovednutrientavailabilityandothersoilconditions,byinoculationofearthwormsatanappropriaterate.Furtherstudiesareneededtoillustratetherelationshipbe-tweenmetalavailabilityandearthwormactivityinthefield.