It is of great practical importance to improve yield and quality of vegetables in soilless cultures. This
study investigated the effects of iron-nutrition management on yield and quality of hydroponic-cultivated
spinach (Spinacia oleracea L.). The results showed that mild Fe-deficient treatment (1 lM FeEDTA)
yielded a greater biomass of edible parts than Fe-omitted treatment (0 lM FeEDTA) or Fe-sufficient treatments
(10 and 50 lM FeEDTA). Conversely, mild Fe-deficient treatment had the lowest nitrate concentration
in the edible parts out of all the Fe treatments. Interestingly, all the concentrations of soluble sugar,
soluble protein and ascorbate in mild Fe-deficient treatments were higher than Fe-sufficient treatments.
In addition, both phenolic concentration and DPPH scavenging activity in mild Fe-deficient treatments
were comparable with those in Fe-sufficient treatments, but were higher than those in Fe-omitted treatments.
Therefore, we concluded that using a mild Fe-deficient nutrition solution to cultivate spinach not
only would increase yield, but also would improve quality.