Replicated fertility trials with four vegetable crops on the limestone soils of Dade County, Fla., have been conducted for 3 years (1993–94 through 1995–96). The purpose was 1) to determine crop nutrient requirements, 2) to calibrate a soil testing model, and 3) to develop additional information for plant sap quick tests. The crops included snap beans, Irish potatoes, sweet corn, and malanga (a.k.a. yautia or tannia, Xanthosoma sagittifolium Schott). Another two field demonstrations using reduced rates of phosphorus on tomatoes were conducted in 1995–96. The involvement of the local fertilizer industry in these trials and grower outreach efforts will be discussed.