By Clint Thompson
Irrigation management is essential in North Florida watermelon plants especially if the current dry period continues in the region. But producers should be wary about how much water they apply this early in the season, according to Bob Hochmuth, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) regional specialized Extension agent in Live Oak, Florida.
“Irrigation here early in the season means to me, if necessary, multiple, short irrigation cycles; no long events because all it’s going to do is push that water and whatever fertilizer that’s in that bed down deep into that bed,” said Hochmuth, who cautions producers about protecting their fertilizer investment. The early part of the season can be challenging for growers to manage fertilizer needs in a drip irrigated cropping system.
“We can lose valuable nutrients to leaching this time of the season with either heavy rainfall events or over-irrigation. We can manage the second one, with a good irrigation management program,” said Hochmuth in his weekly email alert to growers and industry leaders. “Soil moisture sensors are a great tool to keep us on track. But we must have confidence in what properly placed and working sensors are telling us and how to interpret them.”
He added that longer irrigation events will push water well below the top 12 inches of the soil. With the water also goes the soluble portion of fertilizer. The shallow roots of transplants are in danger of never receiving much of that fertilizer. Hochmuth has observed daily irrigation events of at least two hours leading to soluble fertilizer moving 36 inches or more.
Producers will be compelled to irrigate if more rain does not saturate the North Florida soils. Most of the region is either abnormally dry or moderately dry, according to last week’s release of the U.S. Drought Monitor.
“The most critical thing early in the season is to try to have good moisture when they put the plastic down. A lot of this plastic was laid at a time when there was better moisture than there is right now. I wouldn’t want to be putting plastic down, as dry as it is right now, in a lot of this area, unless I have a pivot or have some way to get moisture in that bed,” Hochmuth said. “Putting up a dry bed is really not a good situation. It’s hard to re-wet that bed from shoulder to shoulder. It’s hard to wet it appropriately without a lot of that water moving down in the deep sandy profile.”