Abstract

Nanoscale zerovalent iron (nZVI) has shown promise for soil remediation. This study examined the impact of this nanomaterial on barley and wheat grown in alkaline soil throughout a complete growth cycle, to assess its potential as a fertilizer and to understand its behavior in an uncontaminated matrix. A greenhouse experiment was conducted in which barley and wheat plants were grown in soil treated with a commercial nZVI slurry at 0 and 5% (equivalent to 0 and 8 g kg−1). Physiological parameters were monitored throughout the growth cycle, and plants were harvested after five months. Biomass production, impact on root and leaf ultrastructure, and the concentrations of Fe and other nutrients were determined in several plant tissues. Soil physicochemical properties were not adversely affected by nZVI application, and an increase in Fe availability was observed regardless of the species, from 1 mg kg−1 to 5.2 and 6.6 mg kg−1 in barley and wheat soils, respectively. However, this increase did not translate into higher Fe accumulation in plant tissues at the end of the growth cycle, nor did it enhance plant growth in either species. Therefore, under the experimental conditions evaluated, the application of nZVI as an iron fertilizer cannot be recommended. Notably, both crops exhibited a greater sensitivity to nZVI during early stages of development, as evidenced by significant reductions in chlorophyll content and increased oxidative stress. These initial adverse effects were progressively alleviated as plant growth advanced, with no detectable alterations in cellular ultrastructure, allowing both species to complete their growth cycle.

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