Аннотация:Abstract—The optimal nutritional regime (application of the compound fertilizer at small doses), humidityand temperature conditions, and pH values (weakly alkaline) reduce the content of ascorbic acid (a protectiveantioxidant compound) in Solanum tuberosum L. tubers. Exogenous antioxidants (humic preparations) canbe used to maintain the level of ascorbic acid in commercial products. Field experiments were conducted ontwo soil types and in two climatic regions (Voronezh and Moscow oblasts). The obtained data indicate thatthe application of humic preparations (Life Force Natural Humic Acids used in organic farming, Gumistar,and BIO-complex) and lichen-based Yagel-DETOX, both solely and in combination with the mineral fertilizer, maintains the ascorbic acid level (i.e., prevents its reduction) and increases the yield