Super Journal: an online turf research resource
Super Journal is provided by the PACE Turfgrass Research Institute as a free public service to the turfgrass management community. Our mission is to provide an electronic venue for:
- Superintendents to publish results of their turf research projects and to share them with fellow turf managers.
- Turf researchers to rapidly publish and disseminate their experimental results.
- Superintendents who want assistance in designing, carrying out, interpreting and/or summarizing turf research experiments.
Please see our submission guidelines if you wish to have your report published in Super Journal, and our research guide for information on designing and implementing your own turf research project.
Leaching evaluation conducted at Mission Viejo Country Club
Summary:
Kevin Hutchins, CGCS, superintendent at Mission Viejo Country Club (Mission Viejo, CA) evaluated the impact of leaching poorly draining fairways that have low saturated hydraulic conductivity. The fairway soils run as high as 20% clay and 30 % silt. Estimated saturated hydraulic conductivity is less than 0.4 inches per hour (1 cm/hr). Irrigation was applied slowly in attempt to match soil infiltration rates. Fifteen minute irrigation cycles were followed by two hour soaks over the course of three consecutive days. A total of 5 inches (13 cm) of water was applied. The results showed that leaching reduced soil salinity and nitrogen by about 20%, while chloride was reduced by 40%. Sulfur and sodium levels were slightly reduced, but not significantly. This study illustrates the difficulty encountered when attempting to leach soil salts from soils that have low saturated hydraulic conductivity.
Principal investigators: Kevin Hutchins, CGCS, Mission Viejo Country Club, Larry Stowell, Ph.D. and Wendy Gelernter, Ph.D., PACE Turf
Posted 9/1/08
Using virtual irrigation to forecast disease
Poster presentation at the 2008 American Phytopathological Society meetings, July 26 - 30, Minneapolis, MN.
Authors: Larry Stowell and Wendy Gelernter (PACE Turfgrass Research Institute) and Frank Wong and Chi-Men Chen, University of California Riverside
Click here to view the poster (130 KB)
Summary: Recent research suggests that soil moisture impacts the severity of turf diseases such as anthracnose caused by Colletotrichum cereale, Pythium root dysfunction caused by Pythium volutum, gray leaf spot (GLS) caused by Magnaporthe grisea and brown ring patch (BRP) caused by Waitea circinata var. circinata. The virtual irrigation audit, a simple computer model that predicts the size and location of both wet and dry areas on golf course turf, was designed to provide diagnosticians and turf managers with a precision turfgrass management tool for disease and soil moisture management. In this study, the virtual audit was successfully used to describe the occurrence of GLS and BRP on golf course turf.
Evaluation of Eximo plus Dispatch for reduction of sodium in USGA specification greens
Summary: The results show that Aquatrol's Eximo (a synthetic acid), in combination with Dispatch (a surfactant) had no impact on levels of calcium, sodium, or bicarbonate (measured using Mehlich 3 or saturated paste methods) in the soil. The test, however, was conducted on soils that were low (less than 5%) in calcium carbonate. According to Aquatrols representatives, the product's efficacy relies on the presence of calcium carbonate in the soil.
Therefore, in soils that are low in calcium carbonate, Eximo does not appear to have any positive impact on soil chemistry. The performance of this product in soils with significant calcium carbonate levels remains to be seen.
Full print version of report (113Kb)
Principal investigators: Bruce Williams, CGCS and Patty Reedy (The Los Angeles Country Club)
Cooperators: Larry Stowell and Wendy Gelernter (PACE Turfgrass Research Institute)
Posted 7/20/08
IPM Template Progress Report III, April 2008
The third progress report on our GCSAA-funded two-year grant, "Producing an IPM template" is now available. Full text of April, 2008 report
Brown ring patch project receives GCSAA funding
The project, "Management and Biology of Brown Ring Patch on Annual Bluegrass Greens", led by researchers Frank Wong, Ph.D., University of California, and Larry Stowell, Ph.D., PACE Turf, has received two years of funding from the Golf Course Superintendents Association of America. A total of $62,000 will be provided to the project over a 2-year period. Contributing to this funding were the national GCSAA office, as well as:
- the GCSA of Central California
- the GCSA of Northern California
- the GCSA of Southern California
- Hi-Lo Desert GCSA
- San Diego GCSA
- Sierra Nevada GCSA
- California State Chapter GCSA
Brown ring patch, caused by the fungus Waitea circinata var. circinata is causing increasing damage on Poa annua greens. The full text of the proposal can be reviewed in this document.
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)
Effect of leaching greens on soil chemistry
A research study on the effects of leaching was recently conducted with the cooperation of superintendent Mike Hathaway, CGCS (a PACE advisory board member) and assistant Nathan Radwick at The Bridges at Rancho Santa Fe. The full report has been posted onto the PACE Super Journal website, and the results are summarized below.
Summary: To quantify the benefits as well as any hazards of leaching, soil chemical analyses were performed on G2 bentgrass greens that had been leached by applying 5.5 inches of water over a period of 22 hours. A parallel set of analyses were performed on greens that had not been leached. Significant benefits, as well as some lesser, but potential risks were observed, including:
- Leaching reduced salinity by 37% using saturated paste extraction (SPE) methods or 26% using 1:2 soil to water electrical conductivity evaluations (which were converted to saturated paste equivalents).
- Sodium parts per million was reduced by 30% using SPE and to 33% when evaluated using Mehlich III (M3) extraction.
- Sulfur was reduced by 46% using SPE and by 40% when evaluated using M3 extraction.
- Chloride was reduced by 50% using SPE and by 52% when evaluated using M3 extraction
- Although all of the reductions listed above are beneficial, there was also a significant loss of potassium detected in the leached samples. This indicates that applications of supplemental potassium may be needed following heavy leaching in order to replenish levels to the guideline level of 110 ppm or above (as determined by Mehlich III extraction).
Full print version of report (24Kb)
Principal investigators: Mike Hathaway, CGCS and Nathan Radwick (The Bridges at Rancho Santa Fe)
Cooperators: Larry Stowell and Wendy Gelernter (PACE Turfgrass Research Institute)
IPM Template Progress Report II, May 2007
The second progress report on our GCSAA-funded two-year grant, "Producing an IPM template" is now available. Full text of May, 2007 report
