简介：福雷斯特土壤是自然环境的一个重要部件，并且是许多生物活动的主要媒介。在这研究，由开凿者和推土机(重设备)的土壤损失和排水量在切割上被测量并且充满位于Mazandaran省的森林道路的斜坡，伊朗。土壤损失的体积被切并且充满的斜坡变丑在之间的prismoidal分析估计两次处理(在subgrading和二年下面以后)在斜坡班上3050%和5070%。土壤损失的重量被乘土壤损失(cm3)的体积到一般体积密度(1.3g/cm3)计算。土壤由重设备代替了区域根据土工作被评估宽度。结果显示那台重设备在变丑上有重要效果切斜坡坡度并且充满斜坡长度(p<0.0001)。在二年的时期期间，切割(p<0.0002)并且充满(p<0.0001)斜坡坡度显著地在不同斜坡班上被使变形。由开凿者和推土机的平均土壤损失分别地是160.35t/hayr和429.09t/hayr。而且，土壤由推土机在subgrading进程期间代替了区域比在二个斜坡类上的开凿者大(p<0.05)。玷污损失，在森林道路的排水量能被在subgrading工程使用强大的开凿者减少，特别在陡峭的地面。

简介：Reliablefielddataforallhydrologicparametersareoftenunavailableforwatershedsevenforthoseintensivelymonitored.Intheabsenceofreliablesuchdata,verifiedmathematicalrelationsforanareacanbeusedforotherareaswithsamehydrologicandclimaticregimes.Theobjectivesofthisresearchwere:1)toassessthetotalrunoffandsedimentloss,and2)todeveloprainfall,runoffandsoillossrelationsforfourprominentlanduses(includingdegraded,pasture,forestandagriculturelands)intheHilkotwatershed(Pakistan).Fourexperimentalnaturalrunoffplotswereestablishedonthelanduses(degraded,pasture,forestandagricultureland).ThefieldstudyanddatacollectionwereconductedintheHilkotwatershedfrom1999to2005.Regressionanalysiswasconductedtoestablishrelationsamongrainfall,runoffandsoillossforalllandusesusing.Regressionanalysisindicatedgoodcorrelationwithfielddata.

简介：Thehorizontalaccuracyoftopographicdatarepresentedbydigitalelevationmodel(DEM)resolutionbringsaboutuncertaintiesinlandscapeprocessmodelingwithrasterGIS.Thispaperpresentsastudyontheeffectoftopographicvariabilityoncell-basedempiricalestimationofsoillossandsedimenttransport.AnoriginalDEMof10mresolutionforacasewatershedwasre-sampledtothreerealizationsofhighergridsizesforacomparativeexamination.EquationsbasedontheUSLEareappliedtothewatershedtocalculatesoillossfromeachcellandtotalsedimenttransporttostreams.ThestudyfoundthatthecalculatedtotalsoillossfromthewatersheddecreaseswiththeincreasingDEMresolutionwithalinearcorrelationasspatialvariabilityisreducedbycellaggregation.TheUSLEtopographicfactors(LS)extractedfromappliedDEMsrepresentspatialvariability,anddeterminetheestimationsasshowninthemodelingresults.ThecommonlyusedUSGS30mDEMappearstobeabletoreflectessentialspatialvariabilityandsuitablefortheempiricalestimation.TheappropriatenessofaDEMresolutionisdependentuponspecificlandscapecharacteristics,appliedmodelanditsparameterization.ThisworkattemptstoprovideageneralframeworkfortheresearchintheDEM-basedempiricalmodeling.