PACE Turf - Turfgrass Information Center

Precision Turf Management

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.

Soil Compaction Before and After a Rolling Stones Concert at Petco Park

At the Crop Science Society Meetings of America, which were held in November, 2006 in Indianapolis, IN, we presented the results of one of our more quirky, but enlightening projects, Soil Compaction Evaluation with the Spectrum Technologies' SC-900 Before and After a Rolling Stones Concert at Petco Park. (Document is large -- 1384 KB -- so it will open slowly)

In this study, we teamed up with Petco Park superintendent (and co-author) Luke Yoder to characterize the impact of a huge rock and roll concert on the performance of stadium's soils. To do this, we employed the use of several tools, including the SC 900 compaction meter from Spectrum Technologies, as well as the GPS and precision management equipment that we have previously described.

We found that:

  • Soil compaction did increase after the concert, particularly in the areas where the four cranes (three 30-ton cranes and one 70-ton crane) were operating.
  • Even though the soil was more compacted after the concert, the USGA root zone specification sand handled the traffic well, so that it remained below the threshold of 3 Mpa (435 psi) that can cause problems with turf health.
  • The Spectrum Technologies SC-900 compaction meter performed well

Nozzle selection: more important than you think

Can one sprayer nozzle meet all of the competing demands that turf management places on it? This is the topic covered in our May 22, 2006 presentations at the California GCSA annual meeting in Temecula, CA. Topics covered included the role of nozzles in product efficacy, drift reduction, applications volumes, and the need to water in (or not).

"The great sprayer nozzle debate of 2006, Part 1" (230KB)

"The great sprayer nozzle debate of 2006, Part 2" (563KB)

Some bottom line conclusions:

  • The nozzles that do the best job of enhancing product efficacy while at the same time reducing drift potential are flat fan and air induction nozzles. This is especially true for contact/foliar fungicides and insecticides and post-emerge herbicides
  • The worst product efficacy is seen with flood style nozzles. Unless you are making fertilizer applications, flood nozzles should be avoided. They can reduce pesticide efficacy significantly!
  • For application of contact/foliar products, application volumes of 1 ga to 2 ga/1000 sq ft (44 - 88 ga/acre) are optimal. For application of systemic products, application volumes of 2 ga/1000 sq ft (88 ga/acre) are optimal
  • Contact products should not be watered in after application. Systemic products should be watered in, but only light (1/10") levels are required. In most cases, it is possible to wait until the evening irrigation cycle to water products in.

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