Phytotoxic Effect on Corn and Soybean Due Addition of Nanoiron to the Soil

Abstract

Due to its low cost and high reactivity, nanoiron has been widely used for remediating contaminated soils. However, accumulation of large amounts of iron in the soil may be toxic for plants. This research aims at investigating the possible phytotoxic effects of the presence of nanoparticles of iron in the soil, with emphasis on seedling emergence and initial plant growth of soybean and corn. Nanoiron concentrations of 0, 15, and 30 g/kg of soil were examined. For each concentration, 15 samples each of soybean and corn were studied. The plants were grown in vases with 1 kg of soil in a greenhouse. During the experiment, phytotoxicity symptoms such as inhibition of seedling emergence and initial plant growth and plant color changes were analyzed. Twenty-four days after sowing, the plants were harvested and measurements were taken of the root lengths, the aerial lengths, the total dry mass, and the retention of iron by the plants. While all corn plants emerged at the same time, plants under nanoiron treatments showed several symptoms of phytotoxicity, including necrosis, reddish coloration, and subsequent death. In soybean, the 30 g/kg nanoiron concentration completely inhibited seedling emergence. It was concluded that the addition of nanoiron to the soil causes phytotoxicity in soybean and corn plants, affecting seedling emergence, initial growth, and even causing plant death. The symptom differences observed between corn and soybean in relation to nanoiron exposure have become evident in the experiment and show that the same concentration of nanoiron can affect plant species differently.