Leopold Center for Sustainable Agriculture

Completed Competitive Grant

Understanding the potential of phosphorus transport to water resources via leaching

Project ID: 2002-40

Abstract

Improved management of phosphorus (P) from both manure and fertilizer sources is important because of surface water quality concerns. This study considers possible P loss via leaching through the soil and examines the dynamics of the adsorption/extraction process.

Key Question: To what extent does the lateral movement of water to drain tubes through P-deficient subsoils result in P "extraction" from that water?

Findings: Despite the possibility of quick vertical movement of P in water percolating down to the water table from the soil surface, P concentrations in tile drainage are much lower than in the percolating water due to subsoil extraction. Based on the estimates of amounts of flow and soil P levels, it is predicted that the subsoil extraction process can be a beneficial factor for several decades, if not longer.

Lead investigator: James L. Baker, ISU Agricultural and Biosystems Engineering, et al

Year of grant completion: 2004

This competitive grant project was part of the Leopold Center's Initiative.

Topics: Nutrient management