Yields and Bioactive Substances of Selected European Asparagus Cultivars Grown for Green Spear Production as Influenced by of Post-Harvest Drip Irrigation on Sandy Soil in Central Poland

The field experiment was conducted during the years 2006–2008 on a very light soil in central Poland in an area particularly deficient in water. The key aim of the study was the reaction of 10 European asparagus (Asparagus officinalis L.) cultivars: Ravel, Rambo, Rally, Ramada, Rapsody, Cipres, Plaverd, Backlim, Grolim, Orane, grown for green spear production to surface drip irrigation. Drip irrigation of the asparagus plants had a positive effect both on summer stalks and green spears. A significant increase in the height, number and diameter of summer stalks, as well as an increase in the marketable yield, weight and number of green spears was observed for most of the cultivars. Both factors, the irrigation used and the asparagus cultivars, significantly modified the antioxidant content in asparagus spears. The Rapsody cultivar accumulated significantly more, and the Grolim cultivar significantly less, total polyphenols in asparagus spears at unirrigated plots. An inverse relationship was obtained in the Grolim cultivar with respect to the content of vitamin C, which accumulated the most of it under the irrigation conditions. The Ramada cultivar from irrigated plots contained significantly the highest amount of total carotenoids. In turn, the Cipres and Grolim cultivars from irrigated plots were characterized by the highest antioxidant activity.