土壤水与溶质的运移Contents5.0 Introduction5.1 Classifying and determining of soil water土壤水的类型划分及土壤水分含量的测定5.2 Energy status of soil water土壤水的能态5.3 Soil water movement土壤水的运动5.4 Solute transportation in soils土壤中的溶质运移Soil water土壤水是土壤的最重要组成部分之一；在土壤形成过程中起着极其重要的作用，在很大程度上参与了土壤内进行的许多物质转化过程：矿物质风化、有机化合物的合成和分解等；作物吸水的最主要来源；自然界水循环的重要环节；非纯水，而是稀薄的溶液，溶有各种溶质，还有胶体颗粒悬浮或分散其中。
Principal sources of soil water●Precipitation——Rain, snow, hail(雹）; fog, mist(霜)●Ground water——lateral movement from upslope, upward movement from the underlying rock strata.precipitation Surface devoid of vegetationReachdirectly Vegetated surfaceinterceptedcanopyCanopy throughfall andstemflow atmosphereevaporation infiltration Run offSoil waterDrainage and lostEvapotraspirationThe composition of soil waterSoil water contains a number of dissolved solid and gaseous constituents,many of which exist in mobile ionic form,and a variety of suspended solid components.Base cations(Ca2+, Mg2+, K+, Na+, NH4+)PrecipitationMineral weatheringOrganic matter decomposition Lime and fertilizersourcesH+——a measure of acidity (pH)●CO2Atmosphere ——dissolved in precipitation Soil air ——produced in soil respirationH2O + CO2H2CO3H++ HCO3-Unpolluted rain water: pH>5.6Soil water: pH <5.0●Industrial and urban emission●Organic acids derived from decaying organic material●Released by plants in exchange for nutrient base cations major sourceIron and aluminiumMajor sourcesmineral weatheringacid rainMajor formFe2+, Al3+ionssoluble organic-metallic complexesSoluble anionsNO3-, PO43-Cl-, SO42-HCO3-Mineralisation processesFertilizersAtmosphere sourcesMineral weatheringDissolved organic carbon (DOC) Pollutants (heavy metals et al.)Suspended constitutions☐Small particles of mineral and organic material ☐Often result in discoloration(变污)and increased turbidity(混浊度)of soil water.第一节土壤水的类型划分及土壤水分含量测定Classifying and determining of soil water 一、土壤水分类型及有效性Soil water types and availability土壤水分研究方法能量法数量法从土壤水分受各种力作用后自由能的变化研究水分的能态和运动、变化规律。
