A Citrus Expo presentation about best management practices (BMPs) focused on what growers should be doing now in their irrigation and nutrient management programs. The presentation noted that current BMPs were developed prior to HLB’s discovery in Florida in 2005, and that studies are underway to revise the citrus BMPs for nitrogen and phosphorus.
The presentation was created by University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researcher Davie Kadyampakeni, who works at the Citrus Research and Education Center in Lake Alfred. It was delivered for him by Kelly Morgan, director of the UF/IFAS Southwest Florida Research and Education Center in Immokalee.
Some of the key points from the presentation include the following:
- HLB-affected trees are less efficient in nutrient uptake.
- Current data suggests the need to update secondary macronutrient and micronutrient guidelines for HLB-affected trees to improve yield and canopy size.
- HLB-affected trees need both foliar- and soil-applied nutrients. Growers should aim to keep leaf macronutrients and micronutrients at optimum to high ranges. With macronutrients and micronutrients, researchers observed reduced root dieback and increased root growth because root density was increased by foliar nutrient application, and trees were more efficient in soil-applied nutrient uptake.
- Use soil moisture sensors to help determine if enough water is maintained in the root zone. To minimize nutrient leaching, irrigation decisions should be based on the use of soil moisture sensors recommended for Florida’s sandy soils.
- There is a lag time of about 1.5 years for nutrient applications to affect yield, canopy and tree size.
- Fertigation of nitrogen was a more efficient way to improve leaf nitrogen. Use of biweekly fertigation kept soil nitrate in the top 6 inches.
- Florida Automated Weather Network weather stations can be used along with irrigation apps to schedule irrigation and reduce nutrient leaching.
Source: University of Florida Institute of Food and Agricultural Sciences
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