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<br />Table 2.3. Continued. <br /> <br />Reference <br />Carter ( Conr. ) <br /> <br />Chichester, <br />F, W, et al. <br />1979 <br /> <br />Sarnnis, T. 1>1. <br />and C, M. Hohn, <br />1977 <br /> <br />Swarez, D. L. <br />and <br />J. D. Rhoades <br />1977 <br /> <br />USffi. SCS <br />Salinity <br />report <br />Jan, 1979 <br /> <br />Period ot <br />data <br /> <br />May 1974- <br />April 1976 <br /> <br />1976 <br /> <br />Hypothetical <br />river waters <br /> <br />April 1976 to <br />October 1977 <br /> <br />Crops <br />grCMIt <br /> <br />Pasture and <br />meadow <br /> <br />Wheat, <br />tomatoes, <br />cotton, <br />lettuce, <br />alfalfa <br /> <br />Pasture, <br />alfalfa, <br />small grain, <br />and com for <br />silage <br /> <br />Soil type <br /> <br />Silt 1O?ID <br /> <br />Variable. <br />Marine shales <br />to gravelly <br />terraces. and <br />glacial <br />outwash <br />materials. <br /> <br />Depth of <br />drains <br /> <br />To 130 cm <br /> <br />2 - 2.5 <br />meters <br /> <br />4ft <br />120 cm <br /> <br />7-8ft <br /> <br />Results <br /> <br />quantities of salt, dissolved from <br />soil minerals and slightly soluble <br />salts will be reIIDved by leaching <br />water. (3) There was no measurable <br />buildup in soils from mineral dis- <br />solving for at least 10 years after <br />irrigation was terminated. <br />C1lemi.cal concentrations remained <br />similar throughout the year. Salt <br />quantity is proportional to the <br />flow of water. <br />Negative correlation existed between <br />water quality in the drain and flow <br />rates. <br /> <br />flow EC <br /> <br />(m3/ see) (mnhos/ cm) <br />summer 0.8-0.9 1.3 <br />winter 0.25 2.0 <br />(i) The concentration of the soil waters <br />at the bottom of the root zone (assumed <br />at 4 ft depth) were lower for all river <br />types with high leaching, The salt load <br />in retum flOW', hc:wever, reduced with <br />low leaching. (ii) The data showed that <br />the concentrations of the drainage <br />waters and salt loads all increase with <br />distance ckM1nstream. (iii) Salt was <br />deposited in the soil even with high <br />leaching because CaCD3 was dissolved in <br />the upper quarters and was deposited in <br />the lower quarters, even though there <br />was no net deoosition in the soil with <br />respect to that derived fran irrigation <br />water ner se. (iv) Reduced salt load <br />in rerUm flows mayor may not reduce <br />salt load in the river waters. The <br />reduction depends on the degree of <br />saturation of river water with respect <br />to CaCD3 and gypsun. <br /> <br />In nost of drains EC remained nearly <br />constant even though the flOW' of <br />water doubled. This indicates rela- <br />tively constant solubility of salts <br />in these soils. However, 'Where the <br />flow of water reduced sharply to 0.5 - <br />2 gpm there was sharp increase in the <br />EC. <br /> <br />6&&& <br /> <br />Location <br /> <br />Coshocton, <br />Ohio <br /> <br />~silla <br />Valley, N.M. <br /> <br />Uintah Basin, <br />Utah <br /> <br />