Environmental Impact of Irrigating Turf with Type I Recycled Water

Abstract

As our water reserves diminish, recycled water is increasingly being used for irrigation of turfgrasses. This study was conducted to determine the fate of nutrients contained in Type I recycled water used to irrigate turf and its effect on turf quality. Eighteen plots were randomly assigned to three replications of three irrigation treatments and two grasses. Irrigation treatments included Edwards Aquifer water applied at the evapotranspiration (ET) rate (EA), recycled water applied at the evapotranspiration rate (1XRW), and recycled water applied at 1.1 times the evapotranspiration rate to provide a leaching fraction (LFRW). Grasses included ‘Tifway’ bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt Davy) and ‘Jamur’ zoysiagrass (Zoysia japonica Steud.). Rain, runoff, leachate, and soil samples were collected and analyzed for total salts, Ca, Cu, Fe, Mg, Mn, N, K, Na, and Zn. The use of San Antonio Water System (SAWS) Type I recycled water had no adverse effect on turf quality but did result in a significant increase in soil electrical conductivity (EC) from 0.2518 dS m−1 in the EA treatment to 0.3132 and 0.3171 dS m−1 in the 1XRW and LFRW treatments, respectively. The Ca content increased from 134 108 and 135 467 mg L−1 in the EA and 1XRW treatments to 142 835 mg L−1 in the LFRW treatment. Na concentrations in the soil were not affected by the use of recycled water. The use of recycled water resulted in increased total salts (EC), Na and nitrate (NO3) concentrations in leachate passing below 76 cm. The EC increased from 0.425 dS m−1 for the EA treatment to 0.626 and 0.614 dS m−1 for the 1XRW and LFRW treatments, respectively. Na concentrations in leachate increased from 18.33 mg L−1 for the EA treatment to 49.10 and 52.91 mg L−1 for the 1XRW and LFRW treatments, respectively. Runoff water from treatments irrigated with recycled water exhibited a trend of increased EC, Ca, Mn, and Na.

Assessing environmental impacts of treated wastewater through monitoring of fecal indicator bacteria and salinity in irrigated soils

“…Throughout the study, levels of NO − 3 N and NH + 4 -N measured in the pond and irrigation water were similar to those reported in other treated wastewater irrigation systems (Assadian et al 2005;Alonso et al 2006;Thomas et al 2006). Because NO − 3 is a mobile anion, it presents concern as a potentially leachable contaminant that may impair groundwater quality, but amounts of NO − 3 in the Pacana Park irrigation water were far below levels with reported potential to leach from irrigated soil-turf systems (Anderson et al 1981).…”

Reclaimed Water for Turfgrass Irrigation

“…Elevated levels of organic matter likely contributed to the higher concentrations of BOD 5 and TSS, but TSS were still several magnitudes of order lower than groundwater standards for southeastern Virginia. The higher concentrations of Na and Cl in the reclaimed water contributed to the higher EC, all of which may potentially adversely affect turfgrass growth; however, EC and concentrations of Na and Cl do not appear to be high enough to cause short term damage.…”

“…Long standing recommendations for irrigating with water that contains a high soluble salt content includes using a leaching fraction of 10% [5]. The leaching fraction is the amount of irrigation water above that required by the crop to maintain acceptable root zone salinity.…”

Soil Salinity of an Urban Park after Long‐Term Irrigation with Saline Ground Water

“…Detailed information on soil properties, irrigation water salinity and sodicity, irrigation system uniformity and irrigation amounts for these research reports are listed in Table 2. The range of values reported in these studies underscores how numerous factors, such as climate and irrigation (precipitation, leaching fraction), soil type and original soil salinity, salinity of irrigation water, and system distribution uniformity, all influence and contribute to changes in soil salinity following irrigation with saline water (Devitt et al, 2007;Ganjegunte et al, 2013;Qian and Mecham, 2005;Schiavon et al, 2014;Sevostianova et al, 2011aSevostianova et al, , 2011bThomas et al, 2006). Developing appropriate salinity management and remediation strategies requires detailed information on the distribution of salinity (EC e ) within the turf root zone.…”

“…Therefore, soil samples collected from depths 0 to 15 and 15 to 30 cm at each of the 20 sampling sites were used for calibration. Samples were analyzed for field moisture content immediately after collection using the gravimetric method described by Topp and Ferre (2002). Soil samples were air-dried, ground, and passed through a 2-mm sieve.…”