Use of Humic Substances and Amino Acids to Enhance Iron Availability for Tomato Plants from Applications of the Chelate FeEDDHA

ABSTRACT

Two experiments in consecutive years were conducted in a commercial greenhouse located in the Southeast of Spain. The objective was to test if the addition of commercial organic compounds could improve the uptake of iron (Fe) by tomato plants (Lycopersicon esculentum mill.) cv Daniela. A commercial humic substance (HS) and a mix of amino acids (AA) were used as organic compounds in the first year of the experiment, and FeEDDHA (Q) as a source of iron. Both organic compounds improved iron uptake in comparison to a control without the addition of organic materials, especially the humic substance. A similar experiment was conducted the following year, but part of the chelate was progressively substituted by the humic compound. Results showed that the content of iron in the leaves increased with the substitution without any significant losses of yield or fruit quality. Plant nutrition was also improved because of an increase in the level of phosphorus in the leaves and a decrease in foliar sodium levels indicating a reduction in the effects of salinity.

Keywords:

• chlorosis
• FeEDDHA
• humic substances
• amino acids