[1] We characterized the effect of large-scale (>20 mm) soil physical structure on the age and recalcitrance of soil organic carbon (SOC) in upper (A) and lower (B) horizons of grassland soils from California’s Central Valley. The radiocarbon content of SOC from surfaces and interiors of large-scale soil structural units (‘‘peds’’) was measured in order to characterize the spatial distribution ...

Soil contamination due to the compounds of chlorophenols is very difficult to treat. Among the chlorophenols, pentachlorophenol (PCP) is quite persistent in the environment which causes serious pollution problem to the surface and subsurface environment (Berta et al., 2007). PCP, an important class of compounds, is used in many industrial applications, and is found in the effluent and soil asso...

Aflatoxins are secondary metabolites produced by Aspergillus flavus, A. parasiticus, A. tamari, A. bombycis and A. nomius species. Relative humidity (RH) is one of the most important parameters influencing the development of aflatoxins in pistachio orchards by Aspergillus species. The type of irrigation system affects density and frequency of the Aspergillus species in the soil. In the current ...

Numerical modeling is a critical tool to the U.S. Department of Energy for evaluating the environmental impact of remediation strategies for subsurface legacy waste sites. Unfortunately, the physical and chemical complexity of many sites overwhelms the capabilities of even most state of the art groundwater models. Of particular concern is the representation of highly-heterogeneous stratified ro...

One of the most important factors for appropriate performance of subsurface drainage systems is having adequate discharge for drains. For this purpose, knowledge about effect of drainage parameters change on drain discharge is essential in subsurface drainage systems. In this article, using change all of the drainage parameters by EnDrain software, changes of drains discharge has been investiga...

Snowmelt in mountainous areas is an important contributor to river water fl ows in the western United States. We developed a distributed model that calculates solar radia on, canopy energy balance, surface energy balance, snow pack dynamics, soil water fl ow, snow–soil–bedrock heat exchange, soil water freezing, and lateral surface and subsurface water fl ow. The model was applied to describe r...

Laboratory experiments were conducted to determine the mineralization rates of 1,3-dichloropropene (1,3-D) in surface and subsurface soil samples collected from three sites in Florida with different histories of 1,3-D exposure. Mineralization rates of uniformly labeled (1)C-1,3-D in surface and subsurface samples collected from two of the three sites, one of which was treated with 1,3-D only on...

1 Heterogeneity and lack of sufficient site characterization render accurate and reliable predictions of subsurface flow and transport in the vadose zone notoriously elusive. It is now widely recognized that for quantitative descriptions of subsurface phenomena to be scientifically defensible, they have to be accompanied by some measure of predictive uncertainty. In other words, a major goal of...