Soil Fertilization with Urea has Little Effect on Seed Quality but Reduces Soil N2O Emissions from a Hemp Cultivation

Multipurpose production of hemp has led to renewed interest for this crop cultivation, especially for human nutrition. To date, no information about the influence of nitrogen source on hemp seed quality is available. Hemp is also used for food and beverages due to its nutritional characteristics. This further use of hemp has led to an increase in hemp-grown areas. Therefore, it is important to get more information on the role of nitrogen on the quality production as well as to evaluate the environmental impact of the cultivation technique. In this work, we evaluate the influence of nitrogen source (i.e., NH4NO3 and urea) on the seed fatty acid composition of an edible hemp as well as on the environment in terms of soil N2O emission. Nitrogen source modified seed quality very little. Even if characterized by a lower acidic profile, seed from plants grown under urea and NH4NO3 had a -3/-6 ratio (0.3) within the optimal range from the nutritional standpoint, being considered as the optimal proportion for human metabolism and health. Urea fertilization reduced soil N2O emission. Our findings suggest that nitrogen source seems not to influence seed quality and that urea fertilizer might be more climate-friendly than NH4NO3 in terms of greenhouse gas emissions, in an extensive cultivation of hemp for industrial use.