What's in your water?

Strategies for evaluating your irrigation water quality.

 

With populations increasing and droughts becoming the norm, golf course superintendents will rely more on poorer quality water sources for irrigation and less on freshwater sources.

Alternative water sources can be naturally occurring and/or influenced more by human actions; naturally, mineralogy and weather influence water chemistry. Within these methods, minerals in rocks are dissolved as water passes over and through them. Chemicals may be released (dissolved) into water as microbes decompose organic material. Plants exude chemicals from their roots to increase availability of minerals in soil pore water.

Further, extreme temperatures cause water to expand in rocks, breaking them apart, releasing minerals that were once tightly bound. Humans affect water quality in various ways. Nutrient, pathogenic and pharmaceutical waste can be introduced from treated and untreated sewage. Metal and chemical waste can be released as by-products of industry and mining operations. Urbanization and development expose subsoils that are naturally anaerobic, introduce deicing rock salts and change landscape use.

humans, location play a role

Some water sources are influenced more by man-made actions than natural processes. For example, reclaimed stormwater runoff and treated wastewater are increasingly common irrigation water sources as demand for freshwater increases. Of course, location also plays a role in what’s in your water. Golf courses closer to the coast may have saline water sources from naturally occurring saline aquifers, freshwater aquifers may have salt water intrusion and/or tidally influenced surface waters. Water components often managed include salinity, sodium and bicarbonates. Moving further inland, some areas have pure water problems from water sources with very low mineral content. Iron is the fourth most abundant element in the earth’s crust and can be found in ground waters throughout many areas at varying concentrations.

Regardless of the source, maintaining quality turfgrass using alternative water sources can be challenging and costly. However, knowing what you have to work with is half the battle. Once identified, proper management can lead to healthy turfgrass.

how to Test water sources

Far too often, an irrigation water test is used as a diagnostic tool after turfgrass is exhibiting some type of stress. However, irrigation water tests should be done when the irrigation system is installed and with some frequency, dependent on the outcome of the initial test, location (are you near the coast?) and the potential for fluctuations in water source quality.

Use opaque plastic containers to collect a water sample. Rinse out the bottle three times with the water to be sampled before taking the final sample. Place your name, location, and date on the sample bottle with a permanent marker. Place in a cooler or refrigerator until delivery to the laboratory. It’s best to submit the sample within 24 hours of collection.

Before sampling, identify what laboratory you are sending it to. Many land grant universities have a laboratory that performs irrigation water testing services. Check with your local extension office.

Another option is to use a contract laboratory. Do your homework: the laboratory you select should be certified by the state and or by a nationally accredited program (the two most common are EPA Environmental Laboratory Certification, and certification from the National Environmental Laboratories Accreditation Program). Once a laboratory is selected, it is best to stay with them. Since different analytical methods are used, varying results for the same water quality parameter may be obtained from different laboratories.


 

What’s in your irrigation water?

Use Table 1 (pages 50 and 52) to identify possible problems. The table is intended for irrigation of plants and not for drinking water or for livestock health. The table reviews the origin of where components come from, range of severity, why a component may be a problem, and proper management if it is a problem.

Since courses most likely use the same irrigation water for maintaining their ornamentals as they do their grass, the document includes some specific references to both turf and ornamentals. If the water source is from treated wastewater, other additional parameters should be examined.

GCI

 

Dara M. Park is an assistant professor of turfgrass, soil and water quality, and L.B. "Bert" McCarty is a professor of horticulture at Clemson University.

 

This article has been adapted from a version that was written for the Carolinas Green May-June 2009 issue.

February 2010
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