The soil is constantly changing. Organic matter is deposited on its surface, often in the form of leaves or needles, and is transformed and allocated in the soil environment where it is available to micro-organisms and plants. This transformation occurs at different rates due to the habitat conditions, which also affects the soil chemistry. We will show you in a simple way how this transformation takes place and you will be able to try out a method for determining one of the basic chemical parameters, which is the saturation of the soil sorption complex.