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DELLAI/ALLE Laboratory, Inc. 06 Chemists and Consultants 1910 W.McKinley,SUIM1 110 0 Fresno.CA 9172/ 9 1209 2]16129 1961 E.Tulare Are a Tuba,CA 91224 9 !2091666-0609 SALINITY, SODIUM & FERTILITY ASSAY SOIL INTERPRETATION GUIDE Soil analyses provide information on a soil's nutrient-supplying ability, its salinity, acidity or alkalinity. This information coupled with the field's crop history, water supply and the general level of management are used in making fertilizer and amendment recommendations. The following information is based upon correlation studies conducted under California conditions by university and government researchers. SP SATURATION PERCENTAGE is the grams of water ESP EXCHANGEABLE SODIUM PERCENTAGE is the degree to required to saturate 100 grams of soil. Its which the soil exchange complex is saturated relation to soil texture is as follows: with sodium. It is used to determine the soil permeability and potential crop phytotoxicity. Below 20 Sandy or Loamy Sand W 20 - 35 Sandy Loam Below 10 No permeability problem; however, 35 - 50 Loam or Silt Loam sodium-sensitive crops may show 50 - 65 Clay Loam phytotoxicity such as Chlorosis or 65 -150 Clay slight crop yield reduction. Above 150 Usually (Peat or Muck) 10 - 15 Soils with SP above 50 may have The water-holdingcapacity of a soil when permeability problems and/or p y phytotoxicity. irrigated and allowed to drain is approximately Above 15 Permeability problems are likely on half the SP. About half the water-holding all mineral soils except those with capacity is available for crop use. a SP below 20. Most crops show pHs DEGREE OF ACIDITY OR ALKALINITY of a soil paste phytotoxicity. wet to saturation is expressed as pHs. GR GYPSUM REQUIREMENT is the amount of gypsum or its equ ivaTt required to furnish sufficient Below 4.2 Too acid for most crops. calcium to correct a sodium-caused permeability 4.2 - 5.5 Adapted to growth of acid tolerant problem and/or phytotoxicity. GR is expressed crops. in tons of 100% gypsum per acre-six inches of 5.5 - 8.4 Adapted to growth of most crops. soil. It will be determined when the ESP is Above 8.4 Possible sodium problem. However, above 10, Ca + Mg is less than three times the sodium problems can occur below pHs ECe or pHs is above 8.4. 8.4. LIME LIME when reported by one to four pluses (+) EC, ELECTRICAL CONDUCTIVITY of the saturation indicates that acid-forming amendments such as extract can be expressed as millinmos per sulfur or sulfuric acid may be used in place of centimeter or decisiemens per meter at 25-C is gypsum. The number of pluses is an estimate of an index of salt content. Salt will restrict the amount of lime present. Acidifying �. crop growth as follows: amendments may cause excessive PH reductions if used in the absence of lime. Below 2 No salinity problem for most crops. 2 - 4 Restricts growth of very salt A numeric value is reported when pHs is below sensitive crops. 6.0 which indicates the amount of 100% lime 4 - 8 Restricts growth of all but (CaCO3 in pounds per acre-six inch) required to salt-tolerant crops. adjust pHs to 6.0. 8 - 16 Restricts growth of all but salt-tolerant crops. 8 BORON, expressed as ppm in the saturation Above 16 Only a few salt-tolerant crops make extract, is required for plant growth but may be satisfactory yields. toxic. This analysis is used to evaluate toxicity; for deficiencies, a different soil or Ca CALCIUM + MAGNESIUM ions in the saturation tissue test is necessary. + extract are expressed in milliequivalents Mg per liter. Ca + Mg along with Na is used to Below 0.5 Not toxic for crops but may be calculate ESP, insufficient for some. Above 1 Sensitive crops may show visible Na SODIUM in the saturation extract expressed as injury. mm equivalents per liter is used to calculate 5 Semi-tolerant crops may show visible ESP, injury. 10 Tolerant crops may show visible Cl CHLORIDE in the saturation extract is expressed injury. in�(iequivalents per liter. For most crops, chloride is not a factor when the electrical conductivity is in a safe range.