PACE Turf - Turfgrass Information Center


Virtual Irrigation Audit

In PACE's presentation at the 2007 Crop Science Society of America (CSSA) meetings, we introduced a concept that we have dubbed "the virtual irrigation audit" which will make it possible, in the near future, to conduct an audit of your irrigation system that does not involve catch cans or even running the irrigation system. While catch-can audits are still necessary for a comprehensive evaluation of irrigation system performance, the virtual irrigation audit can be a fast and fairly accurate diagnostic tool. The same system can also be used to evaluate and improve irrigation system designs even before they are installed. In these days of water shortages and drought-related problems on turf, this is an approach that we believe can save time, money and turf damage.

Our presentation can be found at this link: "Virtual Irrigation Audit"(1,288 KB). A brief summary of the presentation appears below.

Irrigation design problems frequently result in turfgrass stress and damage. Although catch-can evaluations to determine irrigation distribution uniformity are the standard practice, they are cumbersome to conduct and are not practical for diagnostic purposes in real-time. To improve the efficiency of visualizing and diagnosing irrigation design problems, we performed virtual irrigation audits using the following tools:

  • a Trimble AgGPS 132 sub-meter GPS receiver
  • HGIS software from StarPal
  • a TDS Recon hand held computer

(For more information on these tools, see this PACE article on "Precision Management Tools")

Golf course green, tee and fairway perimeters, irrigation sprinkler locations, and the theoretical throw of each irrigation head are easily mapped. The graphics that are generated from this process (see rough map, turf racetrack map and green map) illustrate clearly how water is being distributed from irrigation heads, locates where potential problem areas (too wet or too dry) are likely to occur, and helps diagnose the causes of water-related problems.

In the course of our study, we confirmed what many of you already know — that irrigation designs are woefully deficient in delivering water uniformly to the entire turf surface. In some cases, we found portions of greens that received only 50% of the water that was applied to the wettest areas of the same greens. Deep and infrequent irrigation will help to compensate for these flaws in design, but require heavy water use and may not be sufficient in and of themselves on poa greens where roots are shallow. If short irrigation sets (10 minutes per cycle) are necessary (for example, on poa greens), hand watering will be required to even out soil moisture in areas that receive too little water during the cycle.

Testing the Aqua-PhyD Water Conditioner

Summary: A study was designed to evaluate the water quality claims made for the Aqua-PhyD water conditioner, specifically the company brochure’s claim that "Reclaimed water is perfect for the AQUA-PHYD system. It will significantly reduce the salts and chlorides found in reclaimed, run-off, and recycled water".

Analytical tests were conducted on water before and after passing through the Aqua-PhyD water conditioner that had been installed between the irrigation lake and irrigation heads on a California golf course. The results indicate that the Aqua-PhyD water conditioner did not alter any parameters of irrigation water chemical composition, including salts and chlorides, as evaluated using standard analytical chemical methods.

Aqua-PhyD’s literature also claims beneficial effects on soils as well. The impact of the Aqua-PhyD water conditioner on soil quality was not evaluated in this study.

The full print version of this report (14Kb) is now available on PACE's Super Journal website.

Principal investigators: Larry Stowell, Ph.D., CPAg (PACE Turfgrass Research Institute)

Evaluation of the Geonics EM38 for soil moisture assessment

Summary: The success of a turfgrass track lies in the balance between soil conditions that are ideal for horse racing balanced against the needs of the turfgrass plant. One of the most critical components of this complex soil-turf-horse system is soil moisture. Frequently, the high soil moisture conditions that favor ideal turfgrass growth results in conditions that are too wet and slow for ideal racing and horse safety. Conversely, dry conditions that favor racing may be too dry for uniform turfgrass growth and development. Under optimum conditions, the root zone would maintain constant soil strength regardless of soil moisture conditions. However, until that perfect root zone is identified, soil moisture will be a critical component of turfgrass track maintenance, safety and success.

The results provided here suggest that soil moisture measurement using a Geonics EM38 might provide assistance in delivering more uniform soil moisture conditions at the Del Mar Thoroughbred Club (DMTC). Further research is need to confirm that the EM38 readings predict the track performance as evaluated by horse traffic or using mechanical hoof developed by Dr. Michael Peterson.

Full print version of report (680 KB)

Investigator: Larry J. Stowell, Ph.D., CPPP, CPAg

Cooperator: Leif Dickinson, Del Mar Thoroughbred Club

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