Regreening properties of the soil slow-mobile H2bpcd/Fe3+ complex: Steps forward to the development of a new environmentally friendly Fe fertilizer

Abstract

The application of synthetic Fe-chelates stands for the most established agronomical practice to alleviate lime-induced chlorosis, which still constitutes a major agronomic problem. However, the percolation through the soil profile due to the negative charge of the most deployed molecules results in agronomical and environmental problems. H2bpcd/Fe3+ complex features distinctive chemical characteristics, including moderate stability of the Fe(bpcd)+ species (logβML = 20.86) and a total positive charge, and we studied its behavior in soil and regreening effects on cucumber plants. Soil column experiments have underlined that H2bpcd/Fe3+ is retained in more amounts than EDDHA/Fe3+. The new ligand was not proven to be toxic for the cucumber and maize seedlings. A concentration of 20 μM H2bpcd/Fe3+ attained regreening of Fe-deficient cucumber plants grown in the hydroponic solution supplied with CaCO3, similar to that shown by EDDHA/Fe3+. Experiments with a 2 μM concentration of 57Fe showed that cucumber roots absorbed H2bpcd/57Fe3+ at a slower rate than EDTA/57Fe3+. The high kinetic inertness of H2bpcd/Fe3+ may explain such behavior.