The article presents the research results on the effectiveness of fallow lands with green manure crops as predecessors for winter wheat in reproducing the fertility of light chestnut soils, productivity and quality of winter wheat grains in organic crop farming of the Lower Volga region. The research has shown that replacing summer fallow with a fallow with phacelia as a green manure crop increases the supply of organic matter to the soil in comparison with the control variant by 3.09 t / ha, ensures a positive balance of organic matter +4.05 t / ha. In this case, the largest amount of nitrogen, phosphorus and potassium enters the soil with organic matter of winter wheat, respectively, 41.2; 8.6 and 13 kg / ha. It provides the highest positive balance of basic nutrients of nitrogen, phosphorus and potassium in the soil, +16.2; +2 and +11.2 kg / ha, respectively and more economical consumption of soil moisture by winter wheat plants: the water consumption coefficient is 147.5 mm / t; the grain quality of this crop and productivity has improved by 7.5 %.