Evaluation of leaching tactics

Cultural, Soil

Managing soil salts is a challenge wherever rainfall is limited and infrequent. That is why Patty Reedy and Bruce Williams, CGCS at Los Angeles Country Club have taken time to study leaching tactics to refine the process to a science. In their latest study on LACC's USGA spec, A4 bentgrass greens, they leached test greens for 3.75 hours generated the following results:

• The reduction in salinity was the same (about 20%), whether the drains were left open during leaching or they were closed during the initial period of the leaching event followed by opening the drain once the root zone was saturated.
• When catch cans were used to evaluate the precipitation rates on different areas of the test greens, they found a range between 0.8 in/hr (20 mm/hr) and 2.7 in/hr (69 mm/hr). Although this range is very wide, we have seen similarly wide ranges in precipitation rates in other locations, as shown in a recent study on irrigation distribution and turf disease. This variability is at least partly due to general problems in irrigation design that result in uneven distribution patterns (see the PACE Insights, Issues in irrigation: the uniformity myth (254 KB pdf document).
• The more than three-fold range in precipitation rates had a significant effect on the pre-leaching levels of sodium detected in the soil, with the lowest precipitation areas showing the highest sodium levels, as shown in the graph on the right.
• After leaching, the differences in sodium that were a result of differences in precipitation rate had vanished. In other words, leaching produced the desired effect of not only lowering soil salts in all areas of the green, but of also removing the variability in salt accumulation caused by variable precipitation rates.

Principal investigators: Bruce Williams, CGCS and Patty Reedy, The Los Angeles Country Club, Los Angeles, CA.

The full print version of the report is available at Evaluation of leaching methods on USGA specification greens (611 KB pdf document).

Report posted 11/15/08

A summary of precision management resesarch

Precision Turf Management

We have been exploring the use of sensors and precision management for turf for several years, and have found many useful applications, as outlined in some of our previous Updates and articles. We have summarized our research to-date in this field in a poster presentation that we will give at the Crop Science Society of America meetings this week in Houston, TX. You can view and print the poster here, though it is a fairly large (2.4 MB) pdf document. Key cooperators in these studies were PACE Turf members Leif Dickinson (Del Mar Thoroughbred Club), Sandy Clark (Barona Creek Golf Club), and Jeff Beardsley (Big Canyon Country Club).

Overall, we found that soil moisture and turf quality sensors were powerful tools for characterizing turf performance, and for managing turf. But we also found that in their current form, the equipment was difficult to use, with complex data management and interpretation. Equipment manufacturers are now working on more practical versions of the sensor arrays, so that they will be more useful in turf management, hopefully in the near future.

Posted 10/19/08

10 years of monitoring recycled water: what we have learned

Water

Starting in 1999, we had a great opportunity to initiate a long-term study on the effects of recycled water on turf health and management. Thanks to PACE Turf member Jeff Beardsley of Big Canyon Country Club, we were able to study changes in soil chemistry in 14 fairways that were irrigated with recycled water, and 4 fairways that were irrigated with domestic water. The results of this study will be covered in a poster presentation that we will make at the Crop Science Society of America meetings this coming week in Houston, TX. You can view and print the poster her