Soil samples (<2 mm) from the A horizons of three sandy Michigan spodosols of varying productivity were leached with water extracts of Populus grandidentata Michx. leaves. Laboratory leaching experiments were used to simulate natural weathering of soil minerals by hydrogen ions of organic acids and the complexing of cations by organic compounds in the extracts. All of the soil samples released significant amounts of Mg, K, Na, and Fe, and most released Ca. Using data for Fe released by the leachings and existing data for subsoil Fe accumulation and ground water losses in similar soils, an estimate was made of the number of years of field conditions simulated by the laboratory treatments. The annual elemental release through mineral weathering in the A horizon in each soil was then estimated. Although estimated Ca weathering rates were notably low, estimated rates of Na weathering were comparable to those observed for podzol soils in New England.