Yield and Quality Compounds of White Cabbage (Brassica oleracea L. cv. Capitata) under Different Irrigation Levels

This study was conducted in field conditions to determine the response of cabbage to four different irrigation levels, from 2015 to 2016. The experiment was laid out in randomized block design. Plots were irrigated using a drip irrigation system and the irrigation interval was fixed as 4 days for all treatments. Evaporation was determined by Class-A pan. Six organic acids (ascorbic, tartaric, lactic, citric, malic and oxalic) were identified and quantified by HPLC-UV. White cabbage yields were significantly increased by water applications, but deficit irrigation produced negative results. Maximum amounts of ascorbic, lactic, tartaric and malic acids were found in the low water content treatment, while reducing sugar and total sugar increased in the full irrigation treatment. In the study, supplying different amounts of irrigation water caused changes in the growth and quality of white cabbage (Brassica oleracea L.cv. Capitata). When water stress in cabbage production exceeded more than 30%, the yield and, especially, the quality of cabbage decreased significantly. The results revealed evidence that different soil moisture content in the root depth affected the yield, organic acids, and sugar content.