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Abstract
Tomato is a major vegetable crop in Florida, with a total harvested area of approximately 11,000 ha in 2018 and total cash receipts of about 336 million dollars. In 2017, Florida fresh market tomato takes 34 % of the total production value for fresh market category in the USA and ranks third (4.6%) next to orange and strawberry at 13.8 and 5.8 % respectively of the total crop commodity value among all agricultural commodities in Florida. Tomato is a well-studied crop in Florida. However, studies addressing current challenges in the areas of nutrient and irrigation management, environment, soil, and cultural practices would be required to 1) adjust crop requirements to the present high-efficient production condition and 2) understand the effects of current temperature conditions on tomato productivity in south Florida.
To address these challenges, field and laboratory experiments coupled with computer simulations were conducted over multiple seasons in Immokalee, FL. The studies revealed that under appropriate irrigation, nitrogen (N) application rate above 179 kg ha-1 may not improve tomato yield in south Florida. Similarly, this study clearly indicated that application of pre-plant N fertilizer improved tomato biomass accumulation and yield compared to N application at 100% fertigation. Regulated deficit irrigation (RDI) increased tomato root growth with no yield loss compared to full irrigation (FI) resulting in lower water use and greater water use efficiency.
The study also clearly demonstrated that under the current daylight condition, addition of daylength had minimal effects on growing degree day (GDD) accuracy in tomato production in south Florida. It was also observed that the reduced ceiling (RC) model was more accurate than the standard (ST) model for GDD estimation for tomato crop in south Florida. Based on the results from this study, the recommended temperature regime for the estimation of GDD under the climatic and growing conditions in south Florida were 45oF and 95oF for base and ceiling temperatures respectively. Similarly, the Pearson’s regression coefficient between tomato growth or biomass accumulation and GDD was higher compared to the calendar day method. Therefore, the GDD model improved the prediction accuracy of tomato growth and development across growth stages compared to the calendar day prediction method regardless of the weather condition (warm or cold) during the growing season. Tomato production in south Florida is subjected to heat stress especially during the Fall production season with elevated temperatures. The primary effects of higher temperature in tomato crop was yield reduction from lower pollen viability and fruit set. With the predicted increase in global temperature in the future, further increase in temperature suggest a much lower tomato productivity, especially in south Florida. Therefore, adjusting planting dates to periods that allow for a moderate temperature regime would be critical to maintaining the sustainability of tomato industry in Florida.
