For centuries, Peruvian fisherman have noticed an increase in ocean temperature that occurs every few years and impacts their catch. These warming trends in the Pacific Ocean that cause fish to relocate into cooler water tend to occur in December – hence the name El Niño in reference to Christmas. This warming cycle has been in place since the last ice age and the effect it has on global weather patterns varies in interval and intensity.
In recent times, El Niño has occurred at least once every five years. Although regional weather trends are often similar during the different stages of the El Niño-Southern Oscillation (ENSO), there is no guarantee they will be the same every time. Florida usually has above average precipitation during a strong El Niño and is drier during a strong La Niña – the cooling phase of ENSO – but the weather during moderate and mild phases of each phenomenon can basically go either way.
If the weather since December is any indication of things to come, it looks like the 2023-24 El Niño will mean a cloudy, wet winter in Florida and other parts of the Southeast. This is coming on the heels of record drought and rainfall on the west and east coast of Florida, respectively. The agronomic impact of these severe weather trends was covered in the USGA Green Section article “A Tale of Two Cities.”
So, what does a strong El Niño mean for turfgrass managers in Florida and nearby areas?
- Disease pressure will likely be greater due to increased rain, soil moisture and cloudy conditions. Fungicide efficacy can be reduced under these conditions, so application intervals may need to be shortened.
- Soil-borne diseases can compromise turfgrass roots. Use light and frequent foliar fertilizer applications to improve nutrient uptake and turfgrass color.
- Preemergence herbicides also break down quicker during wet weather, so an additional split-application may be required to carry you through the winter, especially if you have Poa annua populations that are resistant to postemergence herbicides.
- Sunlight and temperatures may be lower than normal and applications of pigments, phosphite and colored sand can help increase turf health and color.
- Courses are as busy as ever this winter, so extra traffic management or cart restrictions may be needed to prevent damage on saturated or weak turf.
- On the positive side, more rain will reduce the need to irrigate. This helps courses with lower-quality irrigation water and helps flush bicarbonates and salts through the rootzone.
Now that you know some of the likely effects from a severe El Niño, you can be better prepared and react quickly if weather goes awry. For more strategies on dealing with whatever Mother Nature throws your way, please reach out to your regional USGA agronomist.
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
Chris Neff, agronomist – cneff@usga.org