one and two dimensional contaminant transport by pure diffusion through single layer of fine grained soil was investigated using one and two dimensional laboratory models. these models simulates a simple hydrogeologic situation underneath a solid waste landfill comprising a fine grained soil overlying a bed rock. sodium chloride solution was sued as a contaminant source above a compacted clayey...

Termites are the most important soil fauna in the Sahelian zone of Africa, intensely interacting with the soil. Both the biotic and abiotic state of the soil affect the termite population and activity. The construction by termites of nests, gallery systems or sheetings from soil or from a mixture of soil and other material within the soil horizons or on the soil surface affect the physical and ...

A major problem facing ecologists is obtaining a complete picture of the highly complex soil community. While DNA-based methods are routinely used to assess prokaryote community structure and diversity in soil, approaches for measuring the total faunal community are not yet available. This is due to difficulties such as designing primers specific to a range of soil animals while excluding other...

Large amounts of flue gas desulfurization (FGD) and fluidized bed combustion (FBC) by-products from burning coal, consisting primarily of gypsum, are available for potential use as a soil amendment. However, information is limited on longer-term changes in chemical and physical properties induced over time and over small depth increments of the upper soil profile after applying these amendments...

In direct seeding systems, soil strength variability and crop residues increase the difficulty of seeding operation. Especially when trying to achieve uniform seeding depth that will result in reliable seed germination and plant emergence. An advanced improvement has been accomplished using direct seeding systems. However, some problems still exist in soil-machine interaction due to various rea...

Persistent Organic Pollutants (POPs) and Polycyclic Aromatic Hydrocarbons (PAHs) are important classes of compounds of serious environmental concern. These compounds were measured in waters, sediments and soils from several high altitude sites in the Sagarmatha National Park (Nepal) and included in the Himalayan ridge. In water samples, low-level substituted PCBs and PBDEs, along with more vola...

Soil organic carbon (SOC) and nitrogen (N) contents are controlled partly by plant inputs that can be manipulated in agricultural systems. Although SOC and N pools occur mainly in the topsoil (upper 0.30 m), there are often substantial pools in the subsoil that are commonly assumed to be stable. We tested the hypothesis that contrasting long-term management systems change the dynamics of SOC an...