Interpretation of Chloride and Nitrate Ion Distribution Patterns in Adjacent Irrigated and Nonirrigated Panoche Soils

Abstract

Abstract Salt profiles of sprinkler‐irrigated soils, with known crop histories, were compared with those of adjacent soils which had not been irrigated. The methods described offer, for some areas, new techniques for estimating salt movements toward the water table and for evaluating past performance of irrigation projects. Theoretical concentration curves obtained using van der Molen's application of the Glueckauf theory of chromatography were successfully fitted to CI ‐ and NO 3 ‐ concentration curves found in soils being leached under field conditions. The accumulation of Cl ‐ in the soil profile was used in conjunction with Cl ‐ concentration in the soil solution to obtain an independent estimate of moisture dissipated by evapotranspiration. Evapotranspiration losses of sprinkler applied irrigation water were estimated by this method to range from 78 to 85% in the soils under investigation. Estimates of total applied irrigation water calculated from the accumulation of Cl ‐ in the soil profile were in general agreement with estimates made from crop history.