Seasonal changes over 2 years (2004–2006) in soil moisture content ( v) of frozen alpine frost meadow soils of the QinghaiTibet plateau permafrost region under three different levels of vegetation cover were investigated. Vegetation cover and air temperature changes had significant effects (synergistic effect) on v and its distribution in the soil profile. During periods of soil freezing or tha...

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...

In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and mu...

To date, chloroethyne in the environment has been proposed to occur as a reactive intermediate during the reductive dechlorination of tri- and tetrachloroethene with zerovalent metals. Such artificial conditions might possibly be found at organohalide-contaminated sites that are surrounded by remediation barriers made of metallic iron. In this paper, it is shown that the highly reactive chloroe...

Introduction Thousands of chemical substances, including toxic, persistent, bioaccumulative substances (TPBS), are produced and used world-wide annually 1 . These volatile and semivolatile TPBS may be transported by air both in gaseous phase and adsorbed to atmospheric particles 2 prior to deposition in soil and water. Due to the grasshopper effect, TPBS released may evaporate in warmer climate...

A simple, inexpensive method for measurement of respiration (CO, evolution) under a continuous air-flow was calibrated against an i.r. gas analyzer. Regression equations were developed to apply the method to general soil respiration measurement in the laboratory. The substrate-induced respiration technique was modified. By using 120% PWHC as a standard soil water condition during incubation, in...

Over one billion tons of agricultural, municipal, and industrial wastes with potential uses in agriculture are generated annually in the United States. Many of these materials are applied to agricultural land because of the benefits they provide. These benefits include: providing a nutrient source for crops; improving soil chemical, physical and biological properties; improving water storage an...

abstract soil quality is an essential concept for maximum agriculture production without environmental destruction. studying soil physical quality indicators, that express soil structural stability and soil air-water balance in root zone, is one of the most important aspects of soil quality. so determination of optimal range for pore volume distribution is important and this research carried ou...

the aim of this research was to evaluate some soil physical quality indicators using remotely sensed date, gis and geostatistical methods in baft area that is one of the most important centers of agricultural production in kerman province. therefore, soil samples were collected from 0 to 20cm depth of 183 points based on regular sampling pattern (every 250 meters) and soil physical indicators i...

We analysed the Normalized Difference Vegetation Index (NDVI), calculated from biweekly NOAA Advanced Very High Resolution Radiometer (AVHRR) images for northern Alaska at both regional (latitudinal gradients) and site scales. Our objectives were to determine if tundra types and arctic subzones could be differentiated in terms of intra-seasonal patterns of greenness, and to construct the relati...