NITROGEN RELEASE PATTERNS OF POLYMER COATED FERTILIZERS USED IN THE ORNAMENTAL INDUSTRY IN SOUTH FLORIDA
Applied Research
Henrique Mayer
URBAN COMM HORTICULTURE AGENT
HOMESTEAD
Abstract
\r\n Use of controlled-release-fertilizer (CRF) is one of the Best-Management-Practices (BMPs) utilized by the ornamental industry in South Florida to improve nutrient-use-efficiency (NUE). CRF producers generally claim nutrient release will last for a specific period of time. The prevalence of relatively high temperatures throughout the year could result in faster nitrogen-release rate than what is stated by CRF manufacturers. In Florida, no official laboratory method exists that can verify the nutrient release rates provided on CRF product labels. A laboratory study was conducted to investigate the effect of temperature on the N release patterns of five polymer-coated fertilizers (Nutricote® 18-6-8 Type140, Multicote® 4-Extra 15-7-15 +1.2 Mg, Kingenta® 20-8-10 six-months, Osmocote® Plus 15-9-12,3-months, and Harrell’s ®Polyon 16-6-11 6-months). A long term (180-days) fertilizer incubation method, in water at 25°C, was employed with a short term or quick extraction method (7-days), in water at 100°C to attain polynomial equations of N release as a function of time. Results suggested that all CRFs tested have shorter N-release longevity than the label claimed. High R2 (>0.97) values indicate N-release patterns can be well predicted at 25¢ªC. The quick laboratory method (100¢ªC) shows a high correlation to 25¢ªC methods and can be used to predict N-releases from CRFs within few days. The highest NUE came from F5 treatment with 40% while the lowest was from F6 treatment with 31%. This study indicated that CRFs hold great promise to improve plant growth and NUE but additional research on plant response, environmental effects, and economics is needed.
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Poster has NOT been presented at any previous NACAA AM/PIC
This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.
A poster file has not been provided
Authors: H. Mayer
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Mayer, H. Commercial Urban Horticulture EA II, University of Florida / Miami-Dade Extesion, Florida, 33030