By Tom Nordlie
Florida citrus growers who plan to establish new groves might want to consider high-density planting, according to experts with the Citrus Research and Education Center in Lake Alfred, part of the University of Florida Institute of Food and Agricultural Sciences, or UF/IFAS.
Wider spacing between trees and rows was common decades ago but, with yields down and input costs up, such low-density plantings are less likely to be profitable. The yield declines and cost increases are consequences of the bacterial disease Huanglongbing, also known as HLB or citrus greening, said Michael Rogers, director of the Lake Alfred center.
“In the age of HLB, it costs every grower a great deal more money to produce a box of oranges or grapefruit than it did back in the years when many of our current mature groves were planted,” said Rogers, also a professor with the UF/IFAS entomology and nematology department. “For this reason alone, we recommend that growers approach the issue of planting density with an open mind.”
To help growers and grove managers assess the performance of various planting densities, UF/IFAS citrus economist Ariel Singerman has developed an Excel spreadsheet that is accessible free of charge at https://tinyurl.com/ydyr3384.
Singerman, an assistant professor at the Lake Alfred center, emphasizes that although planting density is a key decision for all growers establishing a new grove, it is not a “one size fits all” proposition.
“Every operation is different,” Singerman said. “So the message we try to communicate to growers is, ‘customize our spreadsheet using the input costs of your operation so as to figure out what planting density would benefit you the most.’ ”
To explore the relationship between planting density, yield, input costs and prices, Singerman led a study analyzing Valencia oranges planted at densities of 145, 220 and 303 trees per acre – for comparison’s sake, 145 trees per acre is approximately the current statewide planting density average. The results, which will be published in an upcoming issue of the journal HortScience, show that groves with higher densities yield more fruit per acre than those with lower density.
“Planting higher-density groves could offset some of the impact of HLB by decreasing the cost of production per box, due to costs being allocated to a higher number of boxes,” Singerman said. “Ultimately, this could contribute to an increase in profitability per acre.”
Singerman notes that start-up costs often represent the most significant hurdle for growers wishing to adopt high-density planting, because the more densely the trees are planted, the greater the initial investment.
However, the state and some private companies currently offer incentives for growers interested in establishing new groves, which could help growers get started with high-density planting. Singerman has written a document describing some of the incentive programs currently available and their requirements for participation, which can be accessed at https://tinyurl.com/ycctqezc.