More Nitrogen Is Not Always Better for Florida Tomatoes
Nitrogen fertilizer is one of the largest input costs in vegetable production, and with fertilizer prices remaining high, growers are increasingly asking a simple question: Can we use nitrogen more efficiently without sacrificing profit?
A recent study led by Dr. Jalpa evaluated conventional urea and polymer-coated controlled-release urea (CRU) for fresh-market tomato production in Florida’s sandy soils. Although CRU fertilizers were nearly three times more expensive than conventional urea, they often generated greater profits by improving nitrogen use efficiency and maintaining or increasing marketable yields.
Key Findings
- Applying more than 125 lb N/acre did not consistently increase tomato yields, even though the current Florida recommendation is 200 lb N/acre.
- Controlled-release fertilizers were particularly profitable during spring tomato production, with marginal return rates ranging from 70% to more than 200%.
- Higher fertilizer costs represented only a small portion of total production costs (about 1–2%), while improved yields substantially increased net returns.
- Conventional urea performed well in some seasons but was not consistently profitable under all environmental conditions.
Why It Matters
This study demonstrates that fertilizer decisions should consider economic returns, not simply fertilizer price. In many situations, applying nitrogen more efficiently with controlled-release fertilizers may improve profitability while reducing the potential for nitrogen losses to the environment.
The findings also reinforce an important principle of nutrient management: more nitrogen does not necessarily produce higher yields. Matching fertilizer programs to crop demand and seasonal conditions can improve both farm profitability and environmental sustainability.
Reference: Jalpa, L., Mylavarapu, R. S., Wade, T., Hochmuth, G., Li, Y., & Rathinasabapathi, B. (2025). Economic Impact of Nitrogen Management Using Controlled-release Formulations for Tomato Production in North Florida. HortTechnology, 35(3), 377–384. https://doi.org/10.21273/HORTTECH05623-25
