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<br />~.... <br />QO <br />~ <br />.....:.l <br /> <br />-', <br />.,.r <br /> <br />five soil textures, Doneen (1963) set up a system of potential salinity but <br /> <br />set limits for each of three soil permeabillties. The chloride hazard as <br /> <br />listed In the Israel Salinity Survey (1964) indicates different levels In <br /> <br />different soil textures. <br /> <br />A criticism of the Soviet soil scientists by a technical U. S. study group <br /> <br />(Bower et a I. 1960) was that they <br /> <br />".. .determine total salinity by weighing the residue <br />obtained upon evaporation of a filtered 1:5 or 1:10 <br />soil water extract to dryness. The results are ex- <br />pressed as percentage of salt on a dry soil basis and <br />soil texture or water retention characteristics are <br />not taken into account In relating salt content to <br />plant growth. <br /> <br />"American soil scientists recognize that plants growing <br />on saline soils respond to the salt concentration of <br />the soil solution, and that with a given salt content, <br />expressed on a dry soi I basis, the concentration of the <br />soil solution in the field moisture range is Inversely <br />related to fineness of texture or water retention capclty. <br />For this reason, most American scientists employ for the <br />determination of salinity an extract obtained at a water <br />content related to the water retention characteristics <br />of the soil, e.g., saturation extract." <br /> <br />The mean conductivities of the top 30 em of sandy 'ndio soils, sandy <br /> <br />Melolahd, loamy Imperial stratified, and Imperial clay complex soils after 70 <br /> <br />years of irrigation with the same Colorado RiveI' water was 2.4, 2.7, 5.0, and <br /> <br />6,2 mmho/cm. These observations support the development of this report around <br /> <br />soil textural units. <br /> <br />Classification of Colorado River wat~:-b.~!ween ~OO and 1400 ppm total <br /> <br />dissolved solids (TDS). <br /> <br />Published analysis of the ionic composition, conductivity, and TDS of the <br /> <br />Colorado River and several drains leading away from agricultural areas where <br /> <br />the river water has been used and drained out of the soil are available, State <br /> <br />of California (1971). If one considers that t;he factors concentrating the <br /> <br />drainage water are the same ones that will operate to concentrate the Colorado <br /> <br />In the future, It Is likely that the drainage salt contents are a reasonable <br /> <br />apprOKimation of the Colorado River salt content if it should reach the same <br /> <br />TDS as that in the drain. With this In mind, table I was developed showing <br /> <br />log regressions of Ec electric conductivity (mag/I) of CI-, Ca., HC03-, Mgy, <br /> <br />Na+, and 504= as a function of TD5 in ppm of all water data from below Imperial <br /> <br />D::>m. <br /> <br />The classification of these projected water salinities would fall within <br /> <br />8 <br />