按一下以編輯母片標題樣式,按一下以編輯母片,第二層,第三層,第四層,第五層,*,Salt-affected Soils,1.通常發生於semiarid and arid regions,annual precipitation evapotranspiration,2.Natural sources of soil salinity,a)Mineral weathering,b)Fossil salts,c)Atmospheric precipitation,3.Local salt accumulation,Soils in low-lying areas,Evaporation,Capillary rise,water table,Salt-affected Soils1.通常發生於semi,1,4.Human Activities,Salts from areas of over-irrigation accumulate in poorly drained areas.,Relatively saline irrigation water are used.,Oil-field development,waste-spreading operation,and crop fertilization,4.Human Activities,2,9受盐害的土壤-国立台湾大学课件,3,灌溉水質,1.Total Dissolved Solids(TDS),大部分之灌溉用水,TDS 2.5 hazardous,1.25 RSC 2.5 potentially hazardous,RSC 1.25 generally safe,Empirical but worked reasonably well,Increasing SAR of,water,Bicarbonate HazardHigh HCO3-c,11,項目,限值,項目,限值,pH 值,6.0 9.0,鈷 (Co)mg/L,0.05,電導度 mho/cm 25,750,銅 (Cu)mg/L,0.2,懸浮固體物 mg/L,100,鉛 (Pb)mg/L,0.1,氯化物(Cl,-,)mg/L,175,鋰 (Li)mg/L,2.5,硫酸鹽(SO,4,-2,)mg/L,200,錳 (Mn)mg/L,2,總氮量(T-N)mg/L,1,汞 (Hg)mg/L,0.005,清潔劑(ABS)mg/L,5,鉬 (Mo)mg/L,0.01,油 脂 mg/L,5,鎳 (Ni)mg/L,0.5,鋁 (Al)mg/L,5,硒 (Se)mg/L,0.02,砷 (As)mg/L,1,釩 (V)mg/L,10,鈹 (Be)mg/L,0.5,鋅 (Zn)mg/L,2,硼 (B)mg/L,0.75,鈉吸著率(SAR),6,鎘 (Cd)mg/L,0.01,殘餘碳酸鈉 RCS(meq/L),2.5,鉻(總)(Cr)mg/L,0.1,水溫,35,表3.1台灣省灌溉用水水質標準(67.7.5府建水字第59931號公告),附註：天然之水質若超過本標準之限值，得不受本標準之限制。,項目限值項目限值pH,12,Characterization of Salt-affected Soils,1.Na-status,(i)ESP(Exchangeable Sodium Percent),直接測定ESP,費時麻煩，且常有誤差,Characterization of Salt-affec,13,(ii)SAR(Sodium Adsorption Ratio),Soil Soln.,做為 exch.-Na status 之 index,Conc.單位：m moles(+)/L,(ii)SAR(Sodium Adsorption Ra,14,9受盐害的土壤-国立台湾大学课件,15,Effects of salts on soils and plants,1.Main effect on plantsOsmotic Effect,Water,Semipermeable membrane,High salt conc.,Effects of salts on soils and,16,Outside the membrane,High salt,Osmotic potential 愈負,Water potential 愈負,Difficult to,extract water,Osmotic adjustment,Production of organic acids or update of salts,使 osmotic potential愈負,water potential 愈負,然而消耗energy,，,並發生葉組織細胞不斷之分裂但不增長之現象,Possible to continuously obtain water,Water potential,Inside the membrane,Outside the membraneHigh salt,17,2.Specific-ion effects,Plants are sensitive to specific ions in irrigation water or soil soln.,Boron,Chloride,ESP Effect,3.Nutritional imbalances,e.g.bicarbonate toxicity 是由於high pH引起iron或其他micronutrients之deficiency,而不是bicarbonate直接引起之effect.,2.Specific-ion effects,18,Other toxic Solutes,B,Li,Na and Cl,B(Boron),缺乏毒害 之間只相差a few mg/L,Other toxic Solutes,19,9受盐害的土壤-国立台湾大学课件,20,Leaching Requirement(LR),D,dw,:Amount of drainage water,D,iw,:Amount of irrigation water,EC,iw,:Electrical conductivity of irrigation water,EC,dw,:Electrical conductivity of drainage water,為了維持Salt balance(Salt entering=Salt leaching)所需之Leaching fraction(假設no salt propitiation,no salt dissolved from soil minerals,and no salt taken up by the crop),Leaching Requirement(LR)Ddw:,21,D,dw,EC,dw,=D,iw,EC,iw,EC,dw,(allowable EC of the saturation extract)can be obtained from existing salt tolerance data(Table 9.2).,e.g.Soybean,EC,dw,5.5 dsm,-1,at 25,DdwECdw=DiwECiw,22,9受盐害的土壤-国立台湾大学课件,23,Reclamation,1 Saline,non-sodic soils,Leaching,ponding-inefficient,basin-furrow method,Reclamation1 Saline,non-sodi,24,Reclamation,2 Saline-Sodic Soils;Sodic soils,a)Decrease ESP,application of gypsum(CaSO,4,2H,2,O),or,tillage(深耕)bring subsoil lime to the surface,對calcareous-sodic soils 施用S,b)Leaching,Reclamation2 Saline-Sodic Soi,25,SAR 60(High-salt water),Soil ESP=40-50,2,nd,leaching with 1,st,fourfold dilution of the high-salt water,150 m mole(+),L,-1,salt conc.,SAR 30,3 Sodic soils,High-salt water-reclamations,1,st,leaching with 600 m moles(+)L,-1,salt conc.,SAR 60(High-salt water)Soil,26,3,rd,leaching with 2,nd,fourfold dilution of the high-salt water,37.5 m mole(+),L,-1,salt conc.,SAR 15,4,th,leaching with 3,rd,fourfold dilution of the high-salt water,9.4 m mole(+),L,-1,salt conc.,SAR 7.5,Problem:Drainage facilities need to be adequate to remove large quantities of salty drainage water.,3rd leaching with 2nd fourfold,27,