Due in part to recent progress in root genetics and genomics, increasing attention is being devoted to root system architecture (RSA) for the improvement of drought tolerance. The focus is generally set on deep roots, expected to improve access to soil water resources during water deficit episodes. Surprisingly, our quantitative understanding of the role of RSA in the uptake of soil water remai...

Water drives the functioning of Earth's arid and semiarid lands. Drylands can obtain water from sources other than precipitation, yet little is known about how non-rainfall water inputs influence dryland communities and their activity. In particular, water vapor adsorption--movement of atmospheric water vapor into soil when soil air is drier than the overlying air--likely occurs often in drylan...

This paper describes the preliminary results of a study conducted by the California Department of Food and Agriculture which compares the soil distribution of herbicides in two ground water basins in the state. In a previous study, residues of several agricultural chemicals were detected in numerous wells in two inland ground water basins, while only one contaminated well was found in two coast...

Nitrogen fertilizer in the form of urea is subject to ammonia volatilization through the activity of the urease enzyme found ubiquitously in soil (Kissel et al., 2008). Nitrate fertilizer is subject to leaching (Randall et al., 2008) or denitrification (Coyne, 2008), depending on the water content of the soil and water movement through the soil. Ammonium forms of N can be fixed (Kissel et al., ...

Nitrogen fertilizer in the form of urea is subject to ammonia volatilization through the activity of the urease enzyme found ubiquitously in soil (Kissel et al., 2008). Nitrate fertilizer is subject to leaching (Randall et al., 2008) or denitrification (Coyne, 2008), depending on the water content of the soil and water movement through the soil. Ammonium forms of N can be fixed (Kissel et al., ...

A thorough understanding of how conservation tillage in ̄uences water quality is predicated on knowledge of how tillage affects water movement. This paper summarizes the effects of conservation tillage on water movement and quality mainly based on long-term experiments on Luvisols at the North Appalachian Experimental Watershed near Coshocton, OH, USA. Conservation tillage can have a much larger...

irrigation management, soil tillage method and fertilizer management play important roles in increasing crop yield and water and solute movement in the soil profile. the present research was conducted to study the effects of a no-tillage system and nitrogen fertilizer on the mineral nitrogen movement and soil moisture under optimum irrigation conditions. the study was conducted at safiabad agri...

KNOEPP, J.D., and SWANK, W.T. 1993. Site preparation burning to improve southern Appalachian pine-hardwood stands: nitrogen responses in soil, soil water, and streams. Can. J. For. Res. 23: 2263-2270. Three paired watersheds treated with a fell and burn prescription were studied to determine the effects on soil, soil water, and stream water. Soil nitrification and mineralization were measured b...

Different numerical and analytical models are presently available that provide the tools to predict pollutant and water transfer processes between the soil surface and the groundwater level. Among the existing models, the Hydrus-1D model has been used for years in the prediction of water and pollutants transfer in the unsaturated zone. The main purpose of this paper was to model the movement of...