IDHA chelates as a micronutrient source for green bean and tomato in fertigation and hydroponics

The new biodegradable chelating agent imidodisuccinic acid (IDHA) has been studied for its application in agriculture. This study was conducted to compare the efficiency of mixed IDHA and ethylene diamine tetraacetic acid (EDTA) formulations to provide Fe, Mn, Zn, and Cu to green bean (Phaseolus vulgaris 'Perfeccion negra polo') and tomato (Lycopersicum esculentum Mill. 'Shiren') plants grown in greenhouses in soil-less and soil cultures in fertigation conditions. The effect on micronutrient concentrations, SPAD index and fruit yield were investigated. In the green bean experiment, control (no chelate applied) plants showed important micronutrient deficiency symptoms and growth reduction, while IDHA treated plants were healthy. Although EDTA provides micronutrients in higher amounts than IDHA, a chryptogamic infection was observed for this treatment but not for the IDHA one. In the tomato grown on rockwool experiment, increments of SPAD index and Zn concentration are higher in plants treated with IDHA than with EDTA, though for the tomato on soil mulch experiment no differences were found among treatments, even the control. The results are in agreement with previously published studies on the behavior of IDHA. The new chelating agent IDHA can substitute EDTA in hydroponics and fertigation cultures as a chelating agent for micronutrients.