Carbon and nutrients released from the mineralization of organic materials can interact with mineral components changing their dynamics in the soil. In this study, mixtures of corn straw, kaolinite, synthetic goethite, and quartz sand were leached with water after 7, 15, 33, 68 and 113 days of incubation at room temperature. Concentrations of soluble carbon, calcium, magnesium, and potassium were measured and accumulated over time. After 200 days, the total carbon remaining in the mixture was quantified. Total calcium, magnesium, and potassium percolated during the experiment were inversely correlated with the amount of kaolinite and goethite in the mixtures, except for potassium in the treatment with goethite. Adsorption of calcium, magnesium, and potassium did not relate with specific surface area of kaolinite and goethite. Otherwise, goethite was more efficient than kaolinite in retaining carbon and this property was clearly related with its surface area.
incubation; percolation; decomposition; minerals