Three years effect of iron and magnesium nano-particles on the stability of aggregates and some soil chemical properties

Little is known about the long term effects of nanoparticles on soil properties. Therefore, the objective of this study was to investigate the three years effects of nanoparticles on aggregate stability and some of the soil chemical properties. Different amounts (1, 3 and 5 percentage by weight) of two types of nanoparticle of metal oxides, MgO and Fe3O4 were mixed with a loamy soil in three replications and their possible effects on different properties of the soil after three years were investigated. The results showed that application of nanoparticles, increased the pH of the soil from 7.7 in the control to 8.1- 9.3 and the electrical conductivity from 0.31 in the control to 0.34 -0.56 dSm-1, due to the increase in the alkali cations. The percentage of calcium carbonate increased from 19.75% in the control to 20.5-22.7% due to the accumulation of nanoparticles in the soil, with the highest increase in three variables with 5% magnesium nano oxide. 3% nano iron oxide significantly increased the cation exchange capacity from 23.50 in the control to 24.28 cmolc/kgsoil. Also the nanoparticles increased the mean weight diameter, due to their high specific surface area, with the greater effect of magnesium nano oxide (increased from 33 to 1242 percentage compared to the control) than iron nano oxide (increased from 97 to 173 percentage compared to the control). In general, the results of this study showed that, nanoparticles with specific physico-chemical properties can affect some properties of soil.