Soil salinity of urban turf areas irrigated with saline water: II. Soil factors

Abstract

With increasing uses of saline water for irrigating urban landscapes, salinization of irrigated soils is becoming a concern. This study was conducted to identify the soil factors, which can affect salt accumulation, and develop a practical method for estimating potentials for soil salinization. Soil samples collected in large number from five golf courses in west Texas, and southeastern New Mexico, 2 large public parks, and 14 municipal ball-fields in El Paso, TX, were analyzed for soil salinity as well as saturation and field moisture contents. Additionally, compacted and uncompacted areas were sampled for soil salinity at selected areas consisting of Entisols (young alluvial soils). Salt accumulation was minimal in deep sandy soils regardless of their differences in soil forming history. Elevated levels of salt accumulation were, however, found in soils with a thick thatch layer, and in shallow Aridisols developed or placed over the calcic horizon, which restricts drainage. High and variable salt accumulation (>10 dS m −1) was found in compacted clayey Entisols in municipal parks, yet salt accumulation in golf course fairways with comparable soil texture was minimal. This difference in soil salinity appeared to be caused by the difference in soil compaction. Soil salinity of clayey Entisols had a highly significant correlation with the saturation water content, a measure of soil texture, and this relationship seemed to be influenced by soil compaction. An empirical formula was developed for estimating soil salinity from salinity of irrigation water, and the saturation water content (or soil textural classes). Once calibrated to local conditions, it can be useful for assessing salinization potential as well as for evaluating soil suitability for irrigation with saline water in areas consisting of Entisols, but probably not in shallow Aridisols where poor subsoil permeability dictates salinization.