Hydraulic property modification of saline-sodic soils by addition of calcium chloride

soils have developed in some irrigated areas of eastern Montana, due in part to increasing total dissolved solids of irrigation water and sodium accumulation in these irrigated soils. This accumulation has resulted in reduced yields, prompting farmers to consider application of amendments without evaluating the potential impact on irrigation return flow quality and/or soil physical properties other than sodium displacement. Previous greenhouse experiments have been conducted with intact soil columns of loam, silt loam, and silty clay loam textures. Medicaao sativa L. was grown in soil columns irrigated with an accelerated salt-loading schedule using past, present and projected future irrigation water qualities from the Powder River. Following the final harvest, two studies were conducted. One study utilized undisturbed soil cores from two of the five replicated soil columns to characterize long-term irrigation and subsequent calcium chloride application effects on soil hydraulic properties and drainage water quality. Identical cores were treated with two rates of calcium chloride, 6.42 kg m-2 and 7.73 kg m-2. Calcium chloride solution was applied to the cores and passed through with a pressure head of 33.0 kPa to simulate free drainage. Leachate was collected and analyzed for sodium concentration. Following amendment application and leaching, replicated Tempe cell measurements in the pressure range 0-100. kPa wer