Technical Abstract: Soils in the Northern Great Plains of North America have lost a substantial amount of their original organic carbon (C) and nitrogen (N) reserves in the last 100 or more years, mainly due to tilled summer fallow. Currently, many soils represent a potential sink for atmospheric carbon dioxide. In this review, we summarized research information on the impacts of tillage, crop residue management, balanced fertilization, manure, crop rotation/diversity and frequency of summer fallow on cultivated cropland, and conversion of cultivated land to perennial grassland on storage of organic C and N in soil. Adoption of no-tillage (NT) increased C sequestration by up to 1.170 Mg C/ha/yr compared to conventional tillage (CT) and up to 0.227 Mg C/ha/yr when compared to minimum tillage (MT). Retaining straw added an additional 1.068 Mg C/ha/yr or 0.400 g C/kg/yr over straw burning and up to 0.695 Mg C/ha/yr or 0.405 g C/kg/yr compared to straw removal practices. Annual application of N, P, or other nutrients increased C sequestration by 0.906 Mg C/ha/yr at 56 kg N/ha under NT and by 1.620 Mg C/ha/yr at 150 kg N/ha under CT. In summary, storage of organic C and N can be increased in cultivated soils by implementing proper soil (elimination of tillage and minimizing summer fallow frequency), crop residue (returning residue), nutrient management (balanced fertilization, and combined use of organic amendments and mineral fertilizers) and land use (conversion of marginal cultivated lands to perennial grassland) practices that prevent loss of C from soil and/or increase C input. Furthermore, it would appear C and N storage in soil provides the accompanying benefits of more sustainable crop production (due to an improvement in soil quality and nutrient supplying power), and reducing the potential for greenhouse gas emissions.