Iron (Fe) innovative fertilizers for a sustainable solution of crop Fe chlorosis

Starting date
February 1, 2021
Duration (months)
Managers or local contacts
Varanini Zeno

Iron (Fe) is the micronutrient required in the largest amount by plants and plays a key role in relevant metabolic processes. Although its relatively high abundance in the earth’s cultivated soils Fe - that is scarcely bioavailable - often limit crop production especially in calcareous soils, which cover over 30% of the Earth’s land surface, in particular in arid and semi-arid regions. From the 1950s plants have been treated with Fe3+ chelates. These ligands may facilitate ion dissolution, for example Fe, from relatively insoluble Fe minerals making the metal ion more available for plant uptake. However, chelates present several problems: percolation through the soil profile due to their total negative charge, poor biodegradability, high price and synthesis of by-products sometimes unknown. The aim of this project is to assess the suitability of two different Fe-containing compounds such as FePO4 nanoparticles (FeP NPs) and the complexes between Fe3+ ion and the racemic form of the ligand N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate (H2bpcd) [Fe(bpcd)]+as innovative Fe fertilizers. These two substances have been chose considering that previous experiments done in our laboratory have shown that FeP NPs can be a source of Fe for plants grown in hydroponics. Furthermore, to the best of our knowledge Fe-complex having positive charge (possibly retained by the negative soil charges) have never been tested as Fe supplier in plant nutrition.
The project is organized in 5 phases:
1) Production and characterisation of the two Fe-bearing compounds.
2) Study of the mobility of FeP NPs and ([Fe(bpcd)]+ in a simplified soil system (packed column experiments).
3) Regreening experiments (FeP NPs and ([Fe(bpcd)]+ and FeEDDHA as control) with cucumber plants grown in hydroponic in the presence of CaCO3; uptake experiments (1 and 24h) with [57Fe(bpcd)]+, 57FeP NPs and 57Fe-EDTA or 57Fe-EDDHA as control.
4) Plant-soil microcosm experiments: cucumber plants grown in a Fe-limiting substrate (artificial soil) without/with [57Fe(bpcd)]+, 57FeP NPs or 57Fe-EDDHA as control.
5) Field experiments on kiwifruit growing in a calcareous soil treated with FeP NPs (the production of which in bulk quantity is already possible); Fe-EDDHA as control.
The final goal of the project is to assess if innovative Fe fertilizers such as FeP-NPs and [Fe(bpcd)]+ could offer the potential to improve the crop NUE and yield in a more sustainable way. We expect, to have a picture of the effects of Fe NPs in the real soil-plant system that will be useful to the industrial partner to make decision about their production and commercialization. Similarly, data that will be obtained for the [Fe(bpcd)]+ complex will be disseminated by the publications of scientific papers and will be used by the industrial partner for evaluate the possibility to develop a pilot plant for the complex production.


Funds: assigned and managed by the department

Project participants

Zeno Varanini
Full Professor
Anita Zamboni
Associate Professor


Research facilities