Poster presented at SANREM IL Annual Meetings, Washington, DC, May 2014. Andisols are soils derived from volcanic ash that make up a mere 1% of the world’s soils. They are geographically localized to regions marked by volcanic activity, including the Andean Highlands of Ecuador, part of the Ring of Fire. Andisols have high organic matter content, high water holding capacity, and high overall native fertility as a result of their unique parent material. However, high rates of phosphorus sorption are also characteristic of many volcanic soils (Andisols) and can limit agronomic productivity. Acid Andisols, like those evaluated in this experiment, experience phosphorus sorption as a result of ligand bonding with amorphous minerals and organic matter, and fixation of phosphate with aluminum and iron oxides. Phosphate removed from the soil solution is strongly held by soil minerals and is not available to plants.