Understanding the fate of iron from foliar-applied Fe nanoparticulate fertilizers in crops using XAS spectroscopy combined with Fe isotopic

To reduce conventional fertilizer environmental inputs, foliar-applied nanoparticulate (NP) fertilizers are being developed. In addition to being more efficient, they will help avoid the contamination of agricultural soils in toxic elements found in conventional fertilizers. However, it remains unclear how foliar-applied NP fertilizers are assimilated into the leaves, and how the nutrients they deliver are used by the crops. Here, we designed a Fe based NP fertilizer to deliver Fe, a crucial nutrient that is often depleted in agricultural soils, and for which plants have developed two acquisition strategies. We propose to follow the fate of foliar-applied Fe from FeNP in two edible plants (tomato, type I, Fe redox-based and wheat, type II, Fe3+ complexation-based) using a multi-technique approach. By combining Fe K-edge XANES and EXAFS measurements with Fe isotopic measurements, we will track the pathways and mechanisms that affect Fe from foliar-applied FeNP fertilizer in our plants.