Biochar land application can potentially be used for carbon sequestration, improving soil quality, and reducing non-point source pollution. Understanding biochar mobility is important because its transport in soil greatly influences its stability, the dynamics of soil microbial communities and organic matter, and the movement of biochar-associated contaminants. Here, the transport of biochar pa...

Soil water content impacts all soil physical, chemical and biological properties. Soil water movement in shallow soil layers has critical importance for plant water use, foundation stability, energy transfer and chemical diffusion. Numerical analysis is one way to study soil water. New numerical methods are presented in this thesis to determine soil water content from time domain reflectometry ...

Radioactive fallout 137CS (cesium-137) deposited across the landscape from atmospheric nuclear tests is strongly absorbed on soil particles limiting its movement by chemical and biological processes. Most 137CS movement in the environment is by physical processes; therefore, 137CS is a unique tracer for studying erosion and sedimentation. Cesium-137 loss from a watershed has been shown to corre...

Gypsum is an excellent source of Ca and S, both of which are required for crop growth. Large amounts of by-product gypsum [Flue gas desulfurization gypsum-(FGDG)] are produced from coal combustion in the United States, but only 4% is used for agricultural purposes. The objective of this study was to evaluate the effects of (1) untreated, (2) short-term (4-year annual applications of gypsum tota...

Slope reinforcement and the use of structural pile elements can be an effective slope remediation alternative when conventional remediation practices (e.g., improved drainage) fail to consider the causal factors leading to slope instability (e.g., strength loss due to weathering). An experimental research program was aimed at developing a rapid, cost-effective, and simple remediation system tha...

In temperate European climates, soil water removal due to vegetation transpiration peaks in summer and soil rewetting from higher levels of precipitation occurs in winter. In clays of high plasticity, the seasonal cycles of drying and wetting cause the soil to experience a volumetric change, resulting in seasonal shrinking and swelling. For a clay slope exhibiting volume change, such behaviour ...

Soil particle size distribution (PSD), one of the most important soil physical attributes, is of great importance to soil water movement, soil erosion and soil solute migration. In this study, the soil PSD of 563 soil samples from the mulched drip irrigated cotton fields in Xinjiang of China were measured by laser diffraction particle size analyzer. The soil PSD characteristics and its relation...

Little is known about the impacts of transgenic plants and micro-organisms on soil biota and processes, despite the large number of field releases of transgenic crops. Recent work has shown that transgenic plants can cause changes in the soil biota (both invertebrates and micro-organisms) associated with these plants. Often the changes are transient but their impact on the soil ecosystem remain...

We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the ...