Abstract: Soil is one of the most precious assets of humanity as it provides support and nutrients for plants, shelter for organisms that live in it, makes life possible. But it is a finite natural resource that is easily damaged so it needs protection and rational management as a result of education and public information ("Decalogue of Soil by the Council of Europe"). Decomposers are a consumer category, mainly fungi and bacteria, which mineralize dead organic matter and close the biogeochemical cycles, so contribute to the recycling of nutrients in ecosystems, protect the life. The project of teaching research, which is described in this paper, was part of the Lyceum course of Environmental Sciences aimed to the theoretical and practical approach of the concept of decomposition. For the preparation of theoretical teaching, it was utilized some school teaching tools and techniques, searched the synonymous and linked terms to decomposition into the Curricula and school books of Lyceum. In the field and in the laboratory, it was materialized measurements of paper decomposition rate, in the forest of the school yard. Measurements received in a sampling period of one school year, with a previous pilot phase, and after statistical analysis, exported conclusions concern the seasonal variations of the soil decomposers’ action, in correlation to the weather conditions.