It is well known that there is a spectrum of pores in a soil profile. The conventional use of a single lumped value of soil hydraulic conductivity to describe a spectrum of hydraulically active pores may have unintentionally impeded the development of field-scale chemical transport theoryand perhaps indirectly hindered the development ofmanagement protocols for chemical application andwaste dis...

The persistence, movement and metabolism of insecticides in soils are affected by various environmental conditions. Field data are presented, showing that phorate—after granular band application—moved in both horizontal and vertical directions. Phorate sulphone was the major metabolite recovered. The metabolism and persistence of this insecticide was also affected by its mode of application. Ut...

The ability of Steinernema feltiae or Heterorhabditis bacteriophora infective juveniles (IJ), when applied to the soil surface, to infect a Galleria mellonella larva at the base of a soil-filled cup (276 cm(3)) was evaluated in the presence and absence of 100 larvae of a non-target insect, the aphid midge Aphidoletes aphidimyza, near the soil surface. In all four trials with either S. feltiae o...

The basic electro-kinetic process is defined by forced/induced movement of target pollutants in soil/sand medium under applied electric field low strength between electrodes of opposite polarities. There are several specific mechanisms that contribute to this movement of pollutants. However, one study suggested that the most important ones are electro-osmosis, electro migration, and electrophor...

A variety of mass-movement processes interact to form complex mass-movement terrains in the western Cascade Range in Oregon. Slow, deep-seated (>5 m depth) processes of creep, slump, and earthflow operate simultaneously and sequentially, resulting in unstable conditions that may initiate rapid, shallow (<5 m) soil mass movements on hillslopes and debris torrents in stream channels. This combina...

Endospores of Pasteuria penetrans were evaluated for their vertical distribution in field soil and their downward movement through soil in the laboratory. In the field trial, the number of endospores attached to second-stage juveniles (J2) of Meloidogyne arenaria race 1 varied greatly in different soil depths. There were higher percentages of J2 with endospores attached in former weed fallow pl...

The basic electro-kinetic process is defined by forced/induced movement of target pollutants in soil/sand medium under applied electric field low strength between electrodes of opposite polarities. There are several specific mechanisms that contribute to this movement of pollutants. However, one study suggested that the most important ones are electro-osmosis, electro migration, and electrophor...

In recent years, researchers have focused on modeling of multicomponent reactive transport and have developed models to study the mobility of potentially toxic heavy metals in the subsurface. In this study, a mathematical model for understanding the fate of a typical heavy metal (lead) in unsaturated soil is developed. The entire modeling activity comprises of three parts. During the first part...

Herbicides show promise to improve the efficiency and economics of forest stand conversion and regeneration. However, the impacts of herbicides on forest ecosystems and the ultimate fate of these chemicals are not completely understood. A major problem in pine regeneration in northern mixed hardwood forests is competition from fast-growing and easily sprouting species like red maple, northern r...

Patterns of soil organic carbon (SOC) vary widely across the landscape leading to large uncertainties in the SOC budget especially for agricultural landscapes where water, tillage and wind erosion redistributes soil and SOC across the landscape. It is often assumed that soil erosion results in a loss of SOC from the agricultural ecosystem but recent studies indicate that soil erosion and its su...