Growth and nitrate accumulation in spinach and lettuce grown in nutrient film technique using either organic or inorganic fertilizers

摘要

High nitrate levels in the tissue of leafy vegetables are of concern for human health. The objective of our study was to compare organic with conventional hydroponic production of lettuce and spinach in order to determine whether organic production would reduce the nitrate levels.Six nutrient film technique (NFT) hydroponics systems were used to grow both spinach (Spinacia oleracea cv. 'King of Denmark') and lettuce (Lactuca sativa cv. 'Simpson Elite') using three different concentrations for both organic and conventional fertilizers. Individual macro-nutrient levels (N, P, K, Ca and Mg) were kept the same for each fertilizer treatment.