SALINE IRRIGATION WATER: EFFECTS ON SOIL CHEMICAL AND PHYSICAL PROPERTIES1

Irrigation is becoming a practical means to use saline waste water. The purpose of this paper is to determine the effects of saline irrigation water on soil chemical and physical properties of a Friona fine sandy loam (Petrocalcic Paleustoll). Field plots were furrow-irrigated for 4 years with two saline waters of different quality at three quantity levels. Irrigation was with either blow-down water from an electrical generating plant (ECW = 12 dS/m, SAR = 11) or city water (ECW = 1.5 dS/m, SAR = 4.5). Soluble salts increased in all irrigated plots, with the highest concentrations in plots irrigated with blow-down water. ECe values increased from 0.4 dS/m in the control (nonirrigated) plots to 6.0 dS/m in plots irrigated with high levels of blow-down water. Soluble Na, Ca, and SAR increased in all irrigated plots, with the highest values occurring in plots irrigated with high levels of blow-down water. Soluble Mg was greatest in the plots irrigated with city water. Hydraulic conductivities (K) were significantly reduced in the Ap horizons of plots irrigated with high and medium levels of blow-down water. K values ranged from 2 mm/30 min in the Ap horizon of high-irrigation, blow-down water plots to 37 mm/30 min in the control plots. K values for the B horizons, were less significantly affected by irrigation treatments. Bulk density and water retention were not significantly affected by irrigation treatments.