Modeling aggregate size distribution of eroded sediment resulting from rain-splash and raindrop impacted flow processe

(整期优先)网络出版时间:2019-02-12
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Soilsusceptibilitytodetachmentandtransportsub-processesoferosionisgenerallycontroledbytheaggregatebreakdownmechanism.Measuringparticlesizeandaggregationtotheestimateerodibilitypotentialofsoilsisimportantundererosiverainfallconditions.TheAggregateSizeDistribution(ASD)isoneofthemostimportantdeterminantsofsoilstructurealongwithsoilorganicmattercontentfordescribingtheefficiencyofapplied,sustainablemanagementstrategies.Thisstudyaimedtocomparetheperformancesofthreedifferentaggregatesizedistributionmodelstopredictthecharacteristicaggregatesizeparameter(mediandiameter,D50)forerodedsedimentfrominterrillerosionprocessesofRain-SplashTransport(RST)andRaindropImpactedFlowTransport(RIFT).TheASDsof1143collectedsedimentsamplesfromtheRSTandRIFTprocessesweremeasuredandmodeledbytheLog-normal,Fractal,andWeibullapproaches.TheD50value,asacharacteristicparameterforaggregatesizedistributions,derivedfromthecumulativeASDcurvewascomparedforsoilsfromdifferentlandusetypesanddifferentslopeandrainfallintensityconditions.TheperformanceofeachmodelwasevaluatedusingtheMeanSquareError(MSE)andCoefficientofDetermination(R^2).TheWeibullapproachwasthemostaccuratemodelshowingthebestfitwiththelowestMSEvalues(0.0002≤MSE≤0.0048)andhavingthegreatestR2values(0.936≤R^2≤0.998)whencomparedwiththeLog-normalandFractalmodels.Herewith,forsemi-aridlanduseandsoil,specificshapeandscaleparametersfortheWeibulldistribution,therespectiveASDsweresuccessfullyre-generatedformodelingtheerodedsedimentofthesimulatedRSTandRIFTinterillprocesses.