Effect of Farming System and Irrigation on Nutrient Content and Health-Promoting Properties of Carrot Roots

The field experiment on growing carrots included I. an organic system without pesticides and mineral fertilization of NPK; a conventional system involving NPK fertilization and pesticides in 100% doses; an integrated system, with doses of NPK and pesticides reduced by 50%; and II. the irrigation of carrot crops, with 1. no irrigation as the control, 2. two irrigations, and 3. multiple irrigations. It was proved that the integrated system had the most beneficial effect on the content of L-ascorbic acid (4.5% and 12%), carotenoids (8–10%), and dietary fiber (higher by 2.19–3.37 p.p.) than that recorded in the conventional and organic system in carrot roots. Moreover, the carrot in the integrated system had the best parameters for O-dihydroxyphenols, selenium, and the total antioxidative potential of the raw material. Organic farming, in turn, resulted in the lowest content of nitrates (2.6 times smaller than in the conventional system) and the lowest total sugar content in carrot roots (4.94 mg 100 g−1), which is 20% smaller than in the integrated system), but it also caused the lowest root yield (39.02 t ha−1). The conventional farming system generated the largest amount of nitrates in the raw material (170.68 mg NO3 kg−1). The irrigation of carrot plantations, regardless of the farming system, improved the nutritional composition of carrot roots by an average of about 0.94 p.p. (dietary fiber), 27% (total sugars), 15% (selenium), 29% (O-dihydroksyphenols), and 8.4% (L-ascorbic acid) and the antioxidative properties of the raw material. Multiple irrigations turned out to be the optimal variant for producing a high carrot root yield, especially in the conventional system (58.74 t ha−1).