Impact of Brackish Groundwater and Treated Wastewater on Soil Chemical and Mineralogical Properties

Abstract

The purpose of this study was to assess the impact of non-traditional water irrigation on the chemical and mineralogical properties of the calcareous clayey Angelo soil from West Texas. The exponential rise in population and climate change is leading to further increase in freshwater (FW) depletion, treated wastewater (TWW) and brackish groundwater (BGW) thus offer the possibility of attractive alternative water resources for irrigated agriculture. To address the differences between TWW and BGW, water samples were collected and analyzed. The water samples were analyzed for salt and nutrient content. Soil samples from three horizons (Ap, A, and B) were obtained from three different fields: Rainfed (RF), BGW irrigated, and TWW irrigated. Soil was analyzed for texture, salinity, sodicity, and carbon content. Clay mineralogy of the three different fields was analyzed using the B-horizons. TWW is slightly saline compared to the moderately saline BGW. Although, the exchangeable sodium percentage (ESP), sodium adsorption ratio (SAR), and electroconductivity (EC) have marginally increased compared to RF, however all the values of interest (SAR<13, ESP<15, pH<8.5, and EC<4) were low indicating no sodicity nor salinity problems. Smectite, illite, and kaolinite were identified in the three B-horizon samples by XRD. Overall, there was no major changes in the soil observed, which deems TWW and BGW as viable replacements for FW in arid and semi-arid regions.