Journal of Soil and Plant Interactions

Sequestrene 138 Fe (Fe-EDDHA), one of the most common fertilizers, is used as a source of iron (Fe) in soilless cultures, but its high price leads to increased production costs. This experiment was conducted to investigate the effect of nano iron chelate (consisting of Fe, Zn and Mn) in comparison with Fe-EDDHA on the micronutrients concentration, leaf photosynthetic pigments and yield of two lettuce (Lactuca sativa L.) cultivars in soilless culture. A factorial experiment using completely randomized design was carried out with two factors of iron fertilizers and lettuce cultivars (Teresa and California) and three replications at Shahrekord University. Lettuce plants were nourished with 20 and 40 μmol L^-1 of Fe in nutrient solution from sources of Fe-EDDHA and nano iron chelate (provided that this fertilizer can supply or is not able to supply Zn and Mn required for the plant). The results indicated no significant difference between the application of 40 μmol L^-1 of Fe from either nano iron chelate (provided that this fertilizer can supply Zn and Mn required for the plant) or Fe-EDDHA fertilizers in respect to leaf chlorophyll and carotenoid contents, root and shoot fresh weights, and shoot Fe concentrations of the studied lettuce cultivars. Although the highest shoot fresh weight (436 g plant^-1) was obtained in 40 μmol L^-1 of Fe as Fe-EDDHA, it was not significantly different with shoot fresh weight (387 g plant^-1) gained by application of 40 μmol L^-1 of Fe as nano iron chelate. Based on the results, nano iron chelate might be an ideal substitution for the Fe-EDDHA in soilless culture of lettuce, however further research is still required to completely evaluate its potential risks to the environment and food safety.