Tomato Production with Controlled Release Fertilizer.

Tomato Production in Florida with Controlled Release Fertilizer Increased environmental concerns and increased production costs for vegetable crops have highlighted the need for growers and consultants to better manage fertilizer programs, increase fertilizer use efficiencies, and reduce N loss to the environment. Controlled-release fertilizers (CRF) are recognized in the BMP manual for vegetables in Florida (www.floridaagwaterpolicy.com) as a recommended production practice for crops grown with seepage irrigation to reduce nitrogen loss. CRF are fertilizer prill that are coated with a polymeric layer that regulates the release of fertilizer into the soil over the growing season based on the fluctuation of soil temperature. If the CRF fertilizer has a release pattern that matches the crop needs, the N uptake of the crop becomes more efficient and possibly results in greater yield or reduced need for N fertilizer. Additionally, if CRF can be applied as a pre-plant application, the need for multiple repeat applications of soluble N fertilizer after leaching rain or irrigation events would be eliminated, resulting in reduced production costs and better environmental stewardship. Most previous work with enhanced efficiency fertilizers has focused on the use of sulfur coated urea (SCU) and urea-formaldehyde (UF) primarily because these products have been used in the fertilizer industry for many more years than CRF products. Using a CRF with tomatoes as a percentage of the pre-plant fertilizer is a relatively new concept. Therefore, testing is needed to determine the best fertilizer sources, rates, and release patterns of N under Florida growing conditions before growers can adapt these CRF fertilizers as a source of N in their fertilizer programs. Using Multicote fertilizer, a controlled release fertilizer produced my Haifa Chemicals; several trials were conducted in several locations in FL. The Multicote CRF was used at different rates and different % of coated material in the pre-plant blends. Multicote urea and Multicote potassium nitrate were used as the CRF portion of the pre-plant blends. Applications rates were also evaluated to determine if the CRF component would produce better efficiency in the pre-plant application. The various trials showed that CRF can be used as a portion of the pre-plant fertility program. Rates and % of coated material varied based on the spring or fall production. The application rates were reduced by as much as 40% of the conventional program with no reduction in yield. The conclusion is that CRF can be used as a portion of a pre-plant fertilizer application to reduce applications rates and increase fertilizer efficiencies in FL tomato production.