期刊级别该如何划分？

1、Soil Types and Textures期刊杂志 http:/ DefinitionsoSoil TexturenThe way a soil feelsnA name given a textural group based on the relative proportions of each size of soil particleDefinitionsoAggregatenMass or cluster of soil particles such as a clod, crumb or granuleoSoil StructurenThe combination or arr

2、angement of soil particles into aggregatesObjectivesoDefine aggregate, soil structure, and soil textureoIdentify and describe the three basic soil particlesoIdentify the major textural classesSOIL - Fundamental ConceptsPrepared by Earl D. LockridgeNational Soil Survey CenterLincoln, NEhttp:/soils.us

3、/education/resources/k_12/tools.htmlSOILoGeologic definition: Loose surface of the earth as distinguished from solid bedrock (support of plant life not required).oTraditional definition: Material which nourishes and supports growing plants (includes rocks, water, snow, air).Air 25%Mineral Matt

4、er 45%Water 25%Organic Matter 5%SOILoComponent definition: Mixture of mineral matter, organic matter, water, and air.SOILoSoil Taxonomy definition: Collection of natural bodies of the earths surface, in places modified or even made by man or earthy materials, containing living matter and supporting

5、or capable of supporting plants out of doors. (Its upper limit is air or shallow water and its lower limit is the depth to which soil weathering has been effective.)Soil TaxonomyoAt the highest level, soils can be recognized in one of 12 categories known as orders. For more information: http:/soils.

6、/soilordersSOILoAs a portion of the landscape: Collection of natural bodies occupying portions of the earths surface that support plants and that have properties due to the integrated effect of climate and living matter, acting upon parent material, as conditioned by relief, over period

7、s of time.Soil Forming ProcessesoTranslocationsoTransformationsoAdditionsoLossesPhysical Properties of SoiloSoil textureoSoil structureoSoil coloroBulk densityThree Fractions of Mineral MatteroSandoSiltoClaySoil ParticlesoSandnLargest of the soil particlesnFeel “gritty”oSiltnMedium sizednFeel soft,

8、silky, or “floury”oClaynSmallest particlesnFeel “sticky” USDA Texture Triangle12 Soil Texture ClassesoSand (S)oLoamy Sand (LS)oSandy Loam (SL)oLoam (L)oSilt Loam (SIL)oSilt (SI)oSandy Clay Loam (SCL)oSilty Clay Loam (SICL)oClay Loam (CL)oSandy Clay (SC)oSilty Clay (SIC)oClay (C)Compositions of each

9、of the 12 texture classes is defined by the USDA Soil TriangleGranularPlatyBlocky(Angular)(Subangular)W edgeColumnarPrismaticExamples of Soil StructureAspects of Soil StructureoThe arrangement into aggregates of desirable shape and sizeoThe stability of the aggregateoThe configuration of the poresFa

10、ctors that Affect Soil StructureoKind of clayoAmount of organic matteroFreezing and thawingoWetting and dryingoAction of burrowing organismsoGrowth of root systems of plantsImportant NoteoAll of these have a loosening effect on the soil, but they have no effect on aggregate stabilityBulk DensityoDet

11、ermined by dividing the weight of oven-dry soil in grams by its volume in cubic centimetersoThe variation in bulk density is due largely to the difference in total pore spaceEffects of Bulk DensityoEngineering propertiesoWater movementoRooting depth of plantsSoil ColoroIndicator of different soil typesoIndicator of certain physical and chemical characteristicsoDue to humus content and chemical nature of the iron compounds present