Yield and Bioactive Compounds of Asparagus (Asparagus officinalis L.) Grown in Open Field and Rain Shelter Systems on Reclaimed Land in Saemangeum

The aim of this study is to provide basic data on the yield and bioactive compound contents of the male asparagus cultivar ‘Avalim’ grown under two cultivation systems, i.e., an open field and a rain shelter house, in the Saemangeum reclaimed land. Spear sprouting, yield parameters, polyphenol and flavonoid contents, antioxidant enzyme activities (catalase, ascorbate peroxidase, peroxidase, and superoxide dismutase), and DPPH and ABTS radical scavenging activities of 22-month-old asparagus cultivated in each system were measured. Spear sprouting occurred approximately 10 days earlier in the rain shelter house than in the open field. The number of asparagus spears per 1000 m2 was approximately 600 higher in the rain shelter house, and the total weight was 21% higher than that in the open field. Polyphenol and flavonoid contents, antioxidant enzyme activities, and DPPH and ABTS radical scavenging activities were higher in the open field than in the rain shelter house. The temperature in the rain shelter house during the cultivation period was 0.6 to 17.4 °C higher than that in the open field, while light intensity was 359.7 μmol·m−2·s−1 higher in the open field. Consequently, cultivation in Saemangeum reclaimed land resulted in higher yields in the rain shelter house, whereas the bioactive compound levels were higher in the open field. Therefore, selecting an appropriate cultivation system based on the intended purpose, focusing on yield or functional quality, when cultivating asparagus on reclaimed land is important.