In Florida, we get both ends of the weather spectrum with our very dry winters and extremely wet summers. This makes managing turfgrass a challenge no matter the time of year. In the winter we hope for the occasional weather front to bring us a cleansing rain and in the summer we search for the spigot to turn off the waterworks.
During the winter, it’s common to experience a buildup of salts in the soil from using less-than-optimum irrigation water and the lack of flushing rain events. When irrigation lakes get low, they can be contaminated by saltwater intrusion and have increased levels of chloride and sodium. These dissolved salts can accumulate in the soil and cause osmotic stress to turfgrass if not managed properly.
A common misconception is that calcium applications are needed to help flush salts from the rootzone in Florida’s sandy soils. The soil and irrigation water in Florida are usually loaded with calcium and, regardless of the form, no other calcium is needed. Instead, use acidifying agents such as ammonium sulfate, elemental sulfur or sulfuric acid injection to react with lime in the soil and make gypsum in place. This reaction ultimately creates soluble sodium sulfate that can be flushed through the soil profile by irrigation or rain.
Bicarbonates and carbonates, which can increase soil pH and reduce nutrient availability, are neutralized by acidity. Acids can also react directly with sodium ions and take them off exchange sites to be replaced by hydrogen, or they can break down bicarbonate salts to create soluble sodium sulfate that can be flushed through the rootzone.
Instead of applying calcium, which forms lime with carbonates and raises pH, try the “acid test” and see if you get better results.
Southeast Region Agronomists:
Chris Hartwiger, director, Agronomy – chartwiger@usga.org
Jordan Booth, Ph.D., director, USGA Course Consulting Service – jbooth@usga.org
John Rowland, Ph.D., agronomist – jrowland@usga.org