Ammonium contamination is one of the most nocive forms of groundwater
contamination caused due to the extensive use of nitrogen fertilizers.
Contaminant transport is governed by the adsorption mechanism, which
varies as the contaminant migrates through different types of soils. It
is important to understand the adsorption mechanism of ammonium ions and
the factors influencing them to predict and mitigate their
contamination. This work attempts to thoroughly investigate the effects
of clay content present in the soil on the adsorption and eventually on
the retardation of ammonium ions movement in the porous media. Ammonium
ions transport was examined for three soil types with different clay
proportions, by column and batch experiments. The experimental results
were verified by simulating ammonium ion migration by numerical modeling
using HYDRUS 2D software. It was observed the ammonium ions adsorption
increases with the increase in the clay content of the soil. Therefore,
greater content of clay in the soil enhances the retardation of ammonium
migration in the soil. Further, it can be construed that the soil clay
fraction ensures a reduction in deeper penetration of ammonium ions as a
contaminant into the subsurface.