Postfreeze Irrigation and Fertilization for Citrus Trees

Irrigation and fertilizer applications are important management tools for Florida citrus growers following the recent freeze event in late January/early February.

Davie Kadyampakeni, associate professor in soil, water and ecosystem sciences at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), discussed both facets of tree maintenance during a postfreeze webinar hosted by the UF/IFAS Citrus Team.

Key irrigation takeaways included:

• Producers should base their irrigation decisions on soil moisture sensors that are recommended for Florida’s sandy soils. This will help minimize leaching.
• Soil moisture sensors also help determine if enough water is being maintained in the root zone.
• Growers should not apply water for two days if they have received at least 0.5 inches of rain.
• Weather updates can be monitored with the Florida Automated Weather Network.

Kadyampakeni advised Florida growers to make sure trees have enough — but not too much — water during the dry months of February and March.

According to UF/IFAS research, soil moisture sensors enhance irrigation scheduling by improving water-use efficiency, which contributes to deeper root growth. This helps avoid excess irrigation and the leaching of vital nutrients.

Key fertilizer takeaways included:

• UF/IFAS recommends high-efficiency fertilizers, especially for trees impacted by citrus greening disease. These fertilizers help expedite tree recovery while improving canopy, yields and juice quality.
• Consistent compost applications in sandy soils improve nutrient retention and water-holding capacity, while increasing the long-term productivity of groves depleted by nutrients.
• Base fertilization on soil and leaf tests to determine the tree’s specific nutrition needs.

Some of the high-efficiency fertilizers include slow-release fertilizers and controlled-release fertilizers (apply once or twice per year for 12-month fertilizers); liquid fertilizer applied via fertigation (apply 12 times per year if fertigating monthly); and foliar fertilizers (apply three to four times per year).