El Niño adds sense of urgency to fall harvest season
by PAUL HOLLIS
AUBURN, Ala.—One of the strongest El Niño climate phases in decades has been building during the past several months, and it could make for a tricky fall harvest season in Alabama and throughout the lower Southeast.
Producers who are readying their peanuts, cotton and soybeans for harvest should think in terms of “the sooner the better,” said Brenda Ortiz, associate professor in the Auburn University College of Agriculture’s Department of Crop, Soil and Environmental Sciences. A primary focus of Ortiz’s research is the impact of weather and climate on agriculture.
“There have been indications since this past spring—based on climate models and sea-surface temperatures in the Pacific Ocean—that we are entering an El Niño climate phase, meaning a cooler and wetter fall and winter,” said Ortiz, whose research explores how rainfall and temperature affect crop yields by influencing plant growth and development rates, in addition to pest and disease dynamics. “The sea-surface temperatures in the Pacific have to be warmer than normal, and that’s the main indication of changes toward the El Niño phase.”
All signs point to one of the strongest El Niño’s in recent years, she said.
El Niño, La Niña and Neutral are the three climate phases of ENSO, the El Niño–Southern Oscillation, Ortiz said. In the Southeast, the ENSO phenomena affect rainfall and temperatures during the fall, winter and spring months, with an El Niño occurring every two to seven years.
Winters and springs are wetter and cooler than normal in El Niño years but drier and warmer than normal in La Niña years. La Niña summers are often rainier and cooler than El Niño summers because of increased tropical storm activity, which is usually suppressed by El Niño.
One doesn’t have to look too far back in history to see when a strong El Niño severely impacted fall harvest and planting activities, Ortiz said.
“In the fall of 2009, farmers in the Southeast had many difficulties harvesting peanuts and cotton, and some cotton was even harvested the following January,” she said. “The strongest El Niño on record occurred in 1997, and the one forecast for this year could top that. For October, November, December and January, the climate prediction models are forecasting an all-time record El Niño,” she said.
But knowing what’s in store for the coming months can help farmers prepare for the worst.
“Producers may want to schedule to have extra equipment on hand, and they’ll want to get into their fields as quickly as possible to harvest peanuts and cotton this fall,” Ortiz said. “They might see significant yields losses if they delay harvesting. It also could prove challenging to find a suitable window of good weather to dig peanuts and defoliate cotton prior to harvest.”
In the Southeast, especially for the southernmost counties of Alabama and Georgia, an El Niño means rainfall above normal and temperatures below average, Ortiz said. These weather conditions also will have an impact on planting wheat and other cover crops.
“I’d recommend that growers plant their wheat and cover crops as early as possible this fall because field conditions will get wetter the further along we go into the year,” she said. “If it’s too wet, getting a good stand could become an issue. Growers might have to increase their seeding rates for these crops to compensate for stand loss.”
Usually, El Niño doesn’t last more than one season. La Niña, on the other hand, can last for more than a year. While wheat yields are generally better than average during an El Niño, farmers in north Alabama may find themselves struggling.
“Soils in that region are heavy, and we’ll be getting rainfall more often and in heavier amounts,” Ortiz said. “The soil will remain wet for a longer period of time, and that might be an issue. Heavy rainfall also could lead to nitrogen leaching.”
Previous research conducted in the Southeast has shown that El Niño weather events are not very favorable for corn, assuming the climate phase continues into the spring of next year, Ortiz said.
“The forecast says El Niño will be dissipating towards the spring of 2016. The worst-case scenario for corn is if El Niño remains into next spring and perhaps throughout next summer.”
The advantage of an El Niño is that aquifers and surface water sources will be recharged, helping farmers irrigate their spring-planted crops next year. It’s also a good opportunity for cattle ranchers, with a moist, cool winter being favorable for planted winter forage.
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