Fall and Spring Phosphorus Fertilization of Potato Using a Dicarboxylic ACID Polymer (Avail®)

A dicarboxylic acid polymer (AVAIL) modifies the soil immediately around fertilizer-potentially improving crop phosphorus (P) uptake efficiency and yield. Study objectives were to evaluate potato (Solanum tuberosum L.) response to seasonal applications of liquid and dry AVAIL blended P fertilizer on calcareous soils with low to moderate soil test P. Field experiments conducted 2005-2008 included comparisons of monoammonium phosphate (MAP; 11-52-0) broadcast and/or ammonium polyphosphate (APP; 10-34-0) liquid band applications with or without AVAIL in various fall or spring applications. AVAIL increased US No. 1 yields for selected P rate/source/timing combinations in each of the four years; increased United States No. 1 yields overall in 2006 and 2008; and increased total yield and yield of large (>284g) tubers in 2006. The greatest responses to AVAIL occurred on soils with high lime concentrations. No seasonal advantage was observed in any case.