Wednesday, August 10, 2016: 2:30 PM
Valdosta Room (Sheraton Hotel Atlanta)
Developing a fast and reliable soil testing method is important for improving soil test efficiency and ensuring reliable fertilizer recommendation. Currently, no official extractant for calcareous soils exists for vegetable growers in Florida. There are, accordingly, no phosphorous (P) fertilizer recommendations available for vegetable production on such soil. The objective of this experiment was to evaluate the effects of different P rates on P uptake, yield, and postharvest quality of tomato (Solanum lycopersicum) grown on a calcareous soil. Six rates of P (0, 29, 49, 78, 98, and 118 kg P ha-1) were applied as pre-plant dry fertilizers. Tomatoes were grown using plasticulture system with drip irrigation during the winter growing season of 2014. Results showed that P rates greater than 29 kg ha-1 produced optimal tissue P content at the early fruit set stage; however, the P tissue contents in all P rates were lower than the optimal range before the first harvest. At 60 days after transplanting (DAT), the total plant biomass and P uptake by leaf, stem, root, and fruit were estimated by linear-plateau model with critical rate at 98 kg P ha-1. At 97 DAT, linear response of P uptake by plant was obtained meaning that as P rates increased the uptake increased. There were no significant differences in P uptake at 30 and 135 DAT. The linear regression model was validated to predict the first harvested total marketable yield, which indicated that fruit yield increased with P application rates increased. The total season marketable yield, ranged from 75.8 to 86.4 t ha-1 among the six P rates, and the tomato postharvest qualities were not significantly affected by P rates. Therefore, based on this experiment with 11.3 mg kg-1 ammonium bicarbonate-DTPA (AB-DTPA) extractable P, the P application rate of 118 kg ha-1 should be recommended to tomato growers for the winter growing season on a calcareous soil in Florida.