The average phosphorus (P) fertilizer rate for United States croplands has increased from 38 to 118 kg ha -1 from 1960 to 2011. During this period, fertilizer use, and other technologies, increased the production of corn, wheat and soybean from 158 to 488 million kilograms annually. This production increase, which has increased food security for many, has come at the cost of adverse environmental impacts and decreasing sustainability of US agricultural systems. The factors affecting the adsorption and desorption of P in soils are poorly understood at the molecular-scale. Improved understanding of how P and dissolved organic matter (DOM) components such as lignin interact with soil mineral surfaces is required for achieving sustainable agroecosystems for crop production. This project proposes to address this knowledge gap through the novel combination of computational molecular dynamic simulation and density functional theory calculations of P and lignin reaction with α-FeOOH and laboratory P adsorption studies in the presence of water-soluble lignin of varying oxidation states. The novel, integrated use of macro-scale laboratory studies with computational chemistry approaches will provide a detailed, molecular-scale understanding of P and organic matter interactions with soil minerals. This fundamental information of P-OM interactions is needed before soil scientists can move beyond an empirical understanding of this key soil interaction to one based on direct chemical mechanisms. We believe that the complementary areas of expertise from different fields will generate data relevant to judicious management of soil resources which can lead to enhanced environmental quality and function.