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Updating Nitrogen Recommendations for Cotton in Florida

Extension Education

Libbie Johnson
UF/IFAS Extension Santa Rosa County


Situation: UF/IFAS collaborating with the Florida Department of Agriculture and Consumer Services, has conducted one of a two-year project to develop improved nutrient management recommendations in conjunction with the Best Management Practices (BMPs) program. The current UF cotton nitrogen (N) rate of 60 lbs/acre was based on non-peer reviewed work from 1981 when average yield was 601 lbs/acre. In 2019 average yields were 930 lbs/acre, a 55% increase. BMP enrollment requires following UF recommendations, but 60 lbs/acre N constraint hinders participation. Objective: 1) Provide justification of updated rates to achieve high yields without impacting water quality and 2) Quantify yield optimization and N leaching under different rates. Methods: A randomized complete block design with four replications and six N treatments (0, 45, 90, 135, 180 and 225 N/acre), allowed for destructive sampling. Nitrogen was broadcast as urea, and one location had lysimeters to quantify leaching. Fertility, aside from N, followed Mehlich-3 recommendations. Sampling included soil, plant tissue, petiole, and leachate. Crop development was recorded, data included stand establishment, NDVI, LAI, and yield. Results: Year one yields establish baseline data is currently being developed.  

Poster has NOT been presented at any previous NACAA AM/PIC

This poster is being submitted only for display at AM/PIC. Poster is not to be judged, but the abstract will be published in the proceedings.

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Authors: Libbie Johnson, Ethan Carter, Hardeep Singh
  1. Johnson, L. EXT AGT III, AGRICULTURE, UF/IFAS Extension, Florida, 32565
  2. Carter, E. Agriculture Agent, UF/IFAS Extension, Florida, 32448
  3. Singh, H. Row Crop Specialist, UF/IFAS WFREC, Florida, 32568