Synthetic organic molecules, particularly pesticides, are extensively applicated on agricultural soils. The mobility, availability and fate of these molecules is controlled by adsorption processes to the soil matrix. The adsorption capacity of organic molecules is influenced by the soil structure and composition which is at this moment still poorly understood and mostly ignored in legislation and recommended dosage. This project aims to provide a better understanding of adsorption in soils with varying composition and structure by adsorption experiments on single and combined soil constituents to assess the contribution of and interactions between these constituents.