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- Author or Editor: Jonathan P. Lynch x
`FTE 30' tomato (Lycopersicon esculentum) transplants were produced in Florida under standard commercial conditions and supplied with one of six treatments: zero, low (20% of the control rate), or high (control) super-phosphate (SP) fertilizer, or 0.5%, 1%, or 2% buffered-phosphorous fertilizer (Al-P). Growth characteristics were evaluated for four sets of transplants, produced in January, April, May, and August. Two sets of transplants were grown in the field in Florida (started in January and August) and one set was grown in Pennsylvania during the summer (started in May). Phosphorus concentration in leachate was measured weekly from one crop. Plants grown with Al-P showed a 72% to 88% reduction in P released in leachate compared with the high SP control. Transplants produced with 1% or 2% Al-P were of equal size and quality compared with transplants produced with conventional (high SP) fertilization, and had greater total root length and specific root length (length per unit root weight). Transplants grown with 0.5% Al-P were sometimes smaller than other fertilized treatments, while no-P plants were very small and grew slowly after transplanting. There were no significant differences in growth, yield, or fruit quality of plants fromtransplants grown with 1% or 2% Al-P or high SP at either site. Therefore high quality tomato transplants can be produced using buffered-P fertilizer, while reducing P leaching from the containers.
The utility of alumina-buffered phosphorus (Al-P) fertilizers for supplying phosphorus (P) to bell pepper (Capsicum annuum L.) in soils with low-P availability was evaluated. Plants were grown at low-P fertility (about 100 kg·ha–1, low-P control; LPC), with conventional P fertilization (205-300 kg·ha–1 annually, fertilizer control; FC), or with one of two Al-P sources (Martenswerke or Alcoa) in 2001–03. The two Al-P fertilizers were applied in 2001; no additional material was applied in 2002-03. Plants grown with Martenswerke Al-P had similar shoot dry weight, root dry weight, root length, leaf P concentration, and fruit yield compared with plants grown with conventional P fertilizer in both 2002 and 2003 seasons. Bell pepper grown with Alcoa Al-P had similar shoot dry weight, root dry weight, root length, leaf P concentration, and fruit yield compared with plants grown without P fertilizer in both seasons. Alcoa Al-P continuously released bioavailable P for 2 years between 2001 and 2002, while Martenswerke Al-P continuously released bioavailable P at least 3 years between 2001 and 2003. These results indicate that some formulations of Al-P can serve as long-term P sources for field vegetable production.