Abstract. The results of a 15-year investigation on the dynamics of organic matter in peat soil under the conditions of sand-mix culture (SMC) are presented. The generalisation of the obtained results show that the SMC of peat soil in combination with the organic-mineral fertilizer system allows stabilisation of the balance of orga­nic matter in arabic layer and conservation of the organic matter below the arabic layer. The application of mine­ral fertilizer only does not allow the creation of a zero balan­ce of organic matter even by using perennial grasses crop rotation.