Quality of water is an issue that affects everyone growing turf for any purpose. The presence of chemical and ionic imbalances in water used for irrigation can lead to reduced turf health, as well as mechanical problems in irrigation equipment caused by scale and other effects. For those who must look after static ponds, water quality will affect algae and plant growth.
Outside of expensive chemical-additive solutions, treatments and remedies for water problems are nearly as varied and wide-ranging as those for arthritis — and determining their efficacy has become even more contentious. Just as some people swear by the use of copper bracelets and tiny magnets in treating their painful joints, you can always find at least one local government council, golf course superintendent, or playing field manager who will support a particular non-chemical water improvement technology. Testimonials from happy users provided by the suppliers of non-chemical treatments are fine and dandy, but you are not going to hear about failed deployments from these sources. Supporting scientific evidence for any of the proposed treatment systems is hard to find, and positive reports tend to be disputed (For an overview of the prevailing scepticism, take a look at http://www.chem1.com/CQ/). Yet even the negative results of scientific studies may not always be accurate, as it seems likely that different systems of water improvement may work only in very specific circumstances, which cannot be reliably reproduced. So what should you do? About the only reasonable course of action is to actually run your own tests and experiments by implementing a solution in a limited manner and then assessing the results.
The basics
Let’s quickly review some of the problems that can occur with water. In any water analysis one of the most important factors will be the reading for Total Dissolved Salts (TDS), usually expressed in milligram per litre (mg/L). Generally speaking, a reading of over 1000 can indicate there may be problems, and anything over 2000 is certainly a problem. A high TDS can prevent the roots of turf from absorbing adequate amounts of water due to the osmotic effect. Basically, the high concentration of salts means the water outside the roots is effectively “drier” than the water inside the roots.
pH is a measure of acidity. Natural water has a pH of between 4 and 9, with the range most favourable to plant growth being between 5.5 and 8.5. Acidic water with a pH of less than 6 can contribute to wear on metal irrigation equipment. Water with a pH of less than 4 can lead to soil acidification.
Specific ions can be harmful to plants and even harm the soil’s physical structure. Ions of sodium, chlorine and boron can actually injure roots, or become toxic as they accumulate in shoot tissue. These ion-caused problems are usually present in situations of high salinity.
Water hardness and scaling
Water hardness can refer to a range of conditions, including high concentrations of ion, manganese, sulphates, carbonates and/or bicarbonates. Frequently it refers to the concentration of calcium or calcium carbonates. Calcium and magnesium carbonates tend to precipitate out as adherent solids on the surfaces of pipes or protuberances into the flow of water, such as irrigation rotors. This can cause irrigation equipment to malfunction, requiring cleaning and/or replacement.
The solutions
There are four basic non-chemical water-conditioning solutions. Electrostatic precipitators induce a significant electrical charge into the water. This is supposed to aid in water infiltration. Catalytic devices create a turbulent flow of water over precious and semi-precious metals, theoretically creating a change in calcium carbonate and hence reducing scale deposits. Ozone and oxygen treatments inject ozone into water, creating hydrogen peroxide and nitric acid, improving oxygenation and the solubility of key minerals. The fourth, and in many ways the most praised and disparaged technique, is the use of magnetic/electromagnetic/electrical field devices (This includes devices that use resonant frequencies, as the claimed effects are essentially the same). The application of magnetic
Algal Field Scrubbing
fields theoretically breaks the weak atomic bonding forces and hence provides increased solubility. A fair number of contradictory studies exist for this technology. Essentially, though much anecdotal evidence supports its effectiveness, there is no reliable scientific proof that it actually works the way it is supposed to work. On the other hand, suppliers of devices that utilise this technology are able to provide a number of testimonials to its effectiveness. The Australian manufacturer Hydrosmart (www.hydrosmart.com.au) is at the forefront of these, and can supply testimonials from a number of Australian shires and councils. The District Council of Kimba, for example, claims that installing a Hydrosmart system meant they went from replacing at least one sprinkler head on its sports oval watering system once a week, to virtually not having to replace any of them. The Wild Dog Destruction Board of Broken Hill, NSW has reported similar success, with Hydrosmart radically reducing the ill effects of their water, and the Regional Council of Goyder in South Australia credits the installation of two Hydrosmart units with solving its algae problems in the Burra Creek in Burra.
A quite balanced view is provided in a 2007 paper by James Newman, writing about trials of water improvement technologies for use in remote Aboriginal communities in Australia. He profiles a wide range of these technologies, assesses their effects, and summarizes the results in a table. While his concerns are not with growing turf, this is a very even-handed and thorough paper. It can be accessed at www.icat.org.au/media/Research/water/Newman-2007-Technical-Review-of-household-scale-prevention-methods.pdf.
Algal Field Scrubbers
What to do, what to do?
As was mentioned earlier in this article, faced with such conflicting claims, about the only sensible solution is to perform some form of testing yourself. To do this effectively, you need to apply some basic scientific principles to your testing. First, select a system that you can use for testing. This should be a stable area that will not be subject to external change factors. If you are testing your system on a pond, for example, choose a small pond that is isolated from other sources of water.
Second, establish a baseline status for the experimental system. What is its current condition? How does it change with seasonal variations? If you are testing the effects of a water treatment system on reducing scaling in irrigation equipment, determine the extent of current scaling as accurately as possible. Third, try to establish a similar area that will not undergo the treatment for comparison purposes. This will help you detect influences that are not directly related to the treatment.
You will likely need to run tests for around four to six months to obtain results that are reliable. Even then, if the results do prove positive, you should consider implementing a water treatment solution in as gradual a manner as possible, continuing your testing. You may find that some solutions have only limited application.
Is it worth it?
As much as it is always a good idea to try out new technologies and to remain open to new developments, an investment in non-chemical means of controlling water quality is one that does not provide guaranteed returns. If water quality is affecting turf quality another approach to try is to attempt to limit salt damage through alternative cultivation practices. This could include twice-yearly deep aeration (up to 30cm) and shallow aeration (up to 15cm) as required. Combined with adequate amounts of irrigation so that salts can be effectively leached, this approach may yield more direct results.
Author: Scott Lewis
