Today tomatoes (Lycopersicon esculentum Mill.) are the number one vegetable crop in Florida, US with 46,100 acres in production in 2002–2003 with the largest growing areas located in the southern half of the state. Yields for the 1996–97 season averaged 36,700 lb acre^–1, which resulted in $462.5 M in on-farm revenue, accounting for 28.9% of the value of the vegetable industry in FL or more than double that of any other vegetable. Commonly practiced with tomato production in FL are soil fumigants, raised and polyethylene–mulched beds, adequate rates and types of fertilizer, irrigation, and pesticides. Fertilizers, mainly for nitrogen (N) are applied in bands on such beds to minimize nutrient leaching during heavy rainstorms. However, lateral and vertical movements of N from the bands as well as rates of N mineralization and nitrification during growing seasons are uncertain in sandy soils. This study is conducted in a southwest FL farmer's field under seepage irrigation using 2 N rates (200 and 300 lb N acre^-1) as soluble N fertilizer, 2 lateral sampling points (on fertilizer bands and under crop), and 3 depths (0–4, 4–8, and 8–12 in) over 20 weeks of winter growing season. The experiment includes plots with and without the crop planted to elucidate N uptake rates by tomatoes. Soil samples are analyzed for ammonium, nitrate (2 N KCl), phosphorus, and potassium (Mehlich-1). The experimental design is a randomized complete block design with 3 replications. Results from this study will help determine optimum N application rates for tomatoes in southwest FL, N transformation dynamics synchronized with the plant's growing demand, and N leaching potential to ground water.