Phosphorus soil test correlation to sugarcane grown on Histosols in the Everglades

Sugarcane (Saccharum spp.) in Florida is principally grown on Histosols in the Everglades Agricultural Area. Soil-test-based P fertil-ization recommendations have not been addressed since the 1970s. The objectives of this research were to evaluate the most acceptable soil test P extractant that best correlates to crop yield, and to define soil test P groupings associated with crop response to applied P. Results will be used in the future to recalibrate soil test data to yield and rate of P application. Phosphorus trials were conducted at four sites on organic soils between 1968 and 1972 and additionally at eight sites on organic soils between 1982 and 1990. Phosphorus applications ranging from 0 to 98 kg P ha* ' were broadcast or row-applied in combination with different cultivars, and/or K, Si, or S rates at 12 sites (multiple experiments used per site per crop). The effectiveness of water, acetic acid, and Mehlich-1 extractable soil P as yield response predictor