Proper irrigation and nutrient management are necessary to maximize root density and tree health, especially in trees infected with HLB.
Davie Kadyampakeni, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) assistant professor, shared a few irrigation and nutrient research updates during the March episode of the All In For Citrus podcast.
Young citrus trees require optimal irrigation management for vigorous vegetative growth, leaf flushing and establishment of a dense canopy.
While some citrus growers have tried deficit irrigation on HLB-infected trees, Kadyampakeni says field trials have shown this practice significantly damages trees.
HLB-infected trees are already undergoing tremendous stress. The added stress of water deficit can be detrimental to the tree, limiting root and canopy growth. Kadyampakeni recommends keeping irrigation at optimal levels at all times for trees displaying HLB symptoms. Soil moisture sensors, irrigation apps and the Florida Automated Weather Network are all great resources to enhance irrigation and performance of young trees, he says.
Supplemental irrigation strategies are best suited for trees not under HLB stress.
HIGHER NUTRIENT RATES
Kadyampakeni is also taking an in-depth look at nutrient management. A project in its fourth year has identified that zinc, manganese and boron rates could be doubled, tripled, and in some cases even quadrupled, without toxicity issues.
“With HLB, root growth is limited,” Kadyampakeni says. “But now, when you increase the rate by two times, three times, or four times the macronutrients, you’re going to see better root growth, better root regeneration and less root dieback.” He says researchers have seen an increase in tree health with yields up by 15% to 30% in most instances. They’ve also seen a significant decrease in fruit drop.
NITROGEN FOR DENSE PLANTINGS
In addition, Kadyampakeni’s team is looking at nitrogen levels to update recommendations to modern spacing practices.
As the Florida citrus industry has transitioned from traditional plantings to high-density plantings in the last decade, one of the big questions growers have faced is how much nitrogen to apply to account for this change.
According to Kadyampakeni, applying between 150 and 200 pounds of nitrogen per acre provided the most benefits. At those rates, higher yield and better canopy were achieved.
Listen to the full interview with Kadyampakeni in the March episode of the All In For Citrus podcast, a joint project of UF/IFAS and AgNet Media.