Kehrer, Charis (2020-11). Impacts of Irrigation Water Quality on Turfgrass Growth, Soil Chemistry, and Fungal Community Diversity in Texas. Master's Thesis.
Sources of water for irrigation use on Texas urban soils have varied in recent years due to the decline in water supplies, urbanization, and frequent and persistent drought conditions. Municipalities are turning to other sources of water for irrigation such as wastewater treatment effluent, harvested rainwater, gray water and saline water or produced water, and others. Wastewater treatment plant effluent has become more common to use in city parks and commercial landscaping. The objectives of this study were to evaluate the relationship between irrigation water chemistry and soil chemistry, turfgrass growth and performance, and soil microbial activity. Treatments included irrigation with saline water, wastewater treatment plant effluent, municipal tap water, reverse osmosis water, and gray water. Overall, soils irrigated with saline had the highest electrical conductivity (EC), sodium, pH, sulfur, and calcium concentrations and sodium absorption ratio (SAR). Irrigation treatment did not have a significant effect on soil microbial activity and had variable effects on turfgrass growth and performance. Principal coordinate analysis and non-metric multidimensional scaling indicated no dissimilarities in fungal community composition in irrigation treatments. Relationships between soil depth, time and irrigation treatment and their effects on soil chemistry were also examined, as well as the effects of water treatment on soil fungal community composition using DNA analysis. Depth and irrigation treatment had an impact on sodium and copper. TDN, DON, salinity, and copper concentrations were significantly higher in December than in November. While relatively short-term in nature, these findings support the use of alternative sources of water for municipal and commercial turfgrass irrigation in areas that are facing water demand and supply issues.