Rainfall impact on sodium leaching at Denver Country Club

Permalink | Cultural, Diseases, Soil,

In the July 13, 2011 Super Journal report, "Rainfall impact on sodium leaching at Denver Country Club" (1.3 MB pdf document), we show the dramatic and positive impact that spring rainfall can have on reducing soil sodium and salinity.

In short, we saw that a 2.5 inch rainfall, which occurred over a 36 hour period during the spring of 2011, resulted in a 41% reduction in sodium, and a 19% reduction in overall soil salts.

In addition to causing general stress to turf and potential issues with soil physical properties, high sodium and high salts are also associated with rapid blight, a disease caused by Labyrinthula terrestris. In years when winter and spring rainfall is low, it may therefore be necessary to leach greens with good quality domestic water in order to avoid reaching the maximum levels of 110 ppm sodium that can result in rapid blight infestation.

Project title: Rainfall impact on sodium leaching at Denver Country Club

Principal investigator: Doug Brooks, Denver Country Club and Larry Stowell, Ph.D., CPAg, PACE Turf LLC

Further reading:

• PACE Turf Super Journal Report, "Rainfall impact on sodium leaching at Denver Country Club" (1.3 MB pdf document) posted 7/13/11
• Spreadsheet for calculating sodium hazard of irrigation water (18 KB Excel spreadsheet)
• Video: sodium accumulation
• PACE Super Journal report: Evaluating the sodium hazard in your irrigation water

Managing sodium with calcium chloride

Permalink | Soil,

In the May 28, 2009 Super Journal report, "TopCal for sodium management during leaching at Mission Viejo Country Club" (756 KB pdf document), a study was conducted to evaluate the ability of TopCal (12% Calcium derived from calcium chloride) to reduce soil salinity levels when it was applied to Poa annua greens prior to leaching. Key conclusions were:

• Leaching of either treated and non-treated greens resulted in significant reductions in soil salinity, chloride and nitrate, but leaching had no impact on soil sodium (parts per million or percentage) on either the treated or non-treated greens.
• Application of TopCal did not result in further reductions in soil salts or sodium, or in an increase in soil calcium in this study. It was simply leaching, whether on the treated or non-treated greens, that provided the only significant reductions in soil salts.
• It is likely that the recommended maximum rate of TopCal (20 gallons per acre) that was applied was not sufficient to provide the desired effects. With pre-treatment calcium levels in the soil at about 1,000 ppm, the additional 13 ppm provided by the TopCal would not be expected to have an appreciable effect on increased calcium levels, or in displacement of sodium. For comparison’s sake, the current standard practice for management of soil sodium relies on multiple applications of gypsum, at a rate of 10 lbs/1000 sq ft. With each gypsum application delivering 50 ppm of calcium, and with monthly applications made (for a total of 600 ppm calcium added to the soil over the course of a year), this strategy has resulted in quantifiable and significant reductions in soil sodium levels under a wide range of conditions. For TopCal to approach this level of performance, the maximum rate would have to be increased almost four-fold, and applications would have be made on a monthly basis.
• A follow-up test that evaluates the impact of gypsum, when used under the same conditions, will be implemented later this year

Bottom line: Leaching, as is well known, is an effective method for reducing soil salts. For further reductions in salts, calcium-based products can be used to displace sodium. Liquid (calcium chloride solution), calcium-based products such as TopCal are much easier to handle than alternatives such as gypsum, but the current labeled rate of application for liquid products is currently too low to generate reductions in soil salts.

Project title: Managing sodium with calcium chloride

Principal investigator: Kevin Hutchins, Mission Viejo Country Club, Mission Viejo, CA

Cooperators: Larry Stowell, Ph.D. and Wendy Gelernter, Ph.D., PACE Turf

Report (756 KB pdf) posted 5/28/09

Changes in soil chemical factors following rainfall and calcium chloride applications

Permalink | Cultural, Soil,

As detailed in the Super Journal report, "Changes in soil chemical factors following rainfall and calcium chloride applications" (24 KB pdf document), calcium chloride, when applied during rainfall periods, can have a positive effect on soil quality, especially in high sodium soils (greater than 110 ppm and 6% of the total extractable cations) that also have excessive sulfur (greater than 800 ppm for ryegrass overseeded bermuda fairways). The potential problem of accumulation of chloride in the soil was not an issue under these conditions. The fact that overall soil salinity was not significantly reduced indicates that either more rain and/or additional applications of calcium chloride will be required before overall salts are reduced.

Project title: Changes in soil chemical factors following rainfall and calcium chloride applications

Principal investigators: David Major and Scott Dey, Shady Canyon golf Club, New Port Beach, CA

Cooperators: Larry Stowell, Ph.D. and Wendy Gelernter, PH.D., PACE Turf

Report posted 3/9/09