REDUCED PHOSPHORUS FERTILIZATION EFFECTS ON YIELD AND QUALITY OF SWEET CORN GROWN ON A CALCAREOUS SOIL

摘要

Sweet corn (Zea mays L.) is a major cash crop grown on approximately 4,000 acres in Miami-Dade County. As sweet corn is intensively managed and fertilized, nutrients (especially P) may accumulate in fields that have been cultivated for many years. A large-scale field trial with reduced rates of P was conducted in a grower's field during the 2002/2003 season. Phosphorus rates were 1.5 (no P added), 38.9 (50% reduced P rate) and 71.5 (grower's standard P rate) lb/acre created by pre-plant applicationsof 8-0-6.6 (N-P-K), 8-3.5-6.6, and 8-6.6-6.6, respectively, and foliar P applications totalling 3.5 lb/acre. Plant population, plant height, leaf chlorophyll content, ear yield (number and weight), and quality (ear length, diameter, tip fill, visual appearance, and flag chlorophyll content) were measured. The effect of reducing P rate was not significant for most measurements. These results suggest that reducing P fertilization for one season did not reduce sweet corn growth, yield, and quality in Miami-Dade County. These results support previous reduced P-rate research in the same area. Applying a half rate of P together with foliar analysis as a means to monitor P nutrition may be a temporary set of practices to reduce P applications without affecting sweet corn yield and quality, and thereby decrease the risk of off-site P movement.