Water Check

Insect, disease and weed problems are all easy to spot in a landscape. But have you ever visited a client’s landscape that’s just not up to par and there are no obvious signs of a problem? The next typical step is to evaluate the soil. If that is OK, what do you do next?

Water quality is often overlooked but can be the source of a declining landscape. Problems associated with irrigation water quality will become more evident with time as demand increases on fresh water sources, and properties will draw on poorer quality water sources for irrigation.

Alternative water sources can be naturally occurring and/or influenced more by human actions. Mineralogy and weathering influence water chemistry. Minerals in rocks dissolve as water passes over and through them. 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.

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.

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. Properties 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.

Testing Water Sources.
As mentioned before, 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.

Write your name, location and date on the sample bottle with a permanent marker. Put the sample 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’re sending it to. Many land grant universities have a laboratory that performs irrigation water testing services. Check with your local extension office.

Once you choose a laboratory, 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 Water?
Use Table 1 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.

This information in the table is primarily geared toward turfgrasses; however, the document includes some specific references to both turf and ornamentals. If your water source draws on treated wastewater, other additional parameters for quality should be examined.

Park is an assistant professor of turfgrass, soil and water quality, and McCarty is a professor of horticulture at Clemson University.

This article has been adapted from a version that was written for the Carolinas Green magazine.