Mike Murphy steps from the truckand strides quickly to an unusual-looking configuration of 25 month-old orange trees.   Could this be a prototype for a citrus grove of the future? He intends to find out.

“With greening disease taking producing trees out, we’re trying to figure how to grow more boxes on smaller acreages,” says Murphy, CEO and executive vice president of Cooperative Producers, Inc., outside Immokalee, Fla.

“Some of our ranch was previously designed for trailer parking, so we decided to take that area and see how many trees we could put on a 50-foot bed. We got together with University of Florida professor Bill Castle and designed a program.”

Castle has experimented with designing and managing high density plantings at the university’s Citrus Research and Education Center at Lake Alfred.

“We put three tree rows on an existing 50-foot bed, planted eight feet apart in the drill,” Murphy says.

That puts 326 trees on an acre— more than double the usual number. Murphy calls this plot a modified advanced production system, using high-density planting, fertigation, and compact trees with efficient root systems.

“We chose semi-dwarfing root stocks,” he says. “Bill has 10 different replicated trials with root stocks, so we had a pretty good idea of what would work best.”

They used one microjet irrigation nozzle for every two trees, rather than the normal one-to-one setup. In addition, drip tape delivers moisture directly to the root zone, which should result in a more compact rooting pattern.

“The size of these trees is good,” Murphy says. “We composted them with a rototiller on a three-foot swath, using composted yard debris from the landfill. We brought it out here and tilled it into the soil.