Expansive soils owe their characteristics to the presence of swelling clay minerals. As they get wet, the clay minerals absorb water molecules and expand; conversely, as they dry they shrink, leaving large voids in the soil. Swelling clays can control the behavior of virtually any type of soil if the percentage of clay is more than about 5 percent by weight. Soils with smectite clay minerals, s...

Eutrophication, a major problem in many fresh and brackish waters, is largely caused by nonpoint-source pollution by P from agricultural soils. This lysimeter study examined the influence of P content, physical properties, and sorption characteristics in topsoil and subsoil on P leaching measured during 21 mo in 1-m-long, undisturbed soil columns of two clay and two sandy soils. Total P losses ...

The development of the Nitrogen Soil Test for Rice (N-STaR) allowed site-specific nitrogen (N) recommendations for rice on silt loam soils in Arkansas. Expansion of the site-specific N test into clay soils and its use in 27 counties in Arkansas necessitated the validation of N-STaR for rice produced on clay soil. In 2014, 6 sites across Arkansas were selected for their wide difference in native...

     Comparing the ability of ST and WRB systems to describe soils with clay-enriched horizons was the aim of the present research. In arid and semi-arid regions of Iran, two study sites were considered. Three pedons at each study site were selected, described and sampled. Soils were classified based on ST (2014) and WRB (2015) systems. The micro-morphological investigations were done to confir...

introduction one concern in the disposal of municipal solid waste (msw) by landfill is the production of leachate. acidic water is capable of dissolving elements from the waste; and, as a result, the leachate can become quite contaminated. one of the heavy metals present in leachate, cadmium poses a great concern in terms of environmental contamination since it is toxic to nearly all living org...