Utility of alumina-buffered phosphorus fertilizer for vegetable production

The utility of alumina-buffered phosphorus (AI-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 AI-P can serve as long-term P sources for field vegetable production.