Three study sites were selected on zonal sites from north to south along a climate gradient in Arctic Alaska. Air andmineral soil surface temperatures of nonsorted circles and adjacent well-vegetated tundra plots were monitored from September 2003 through September 2004, and the depths of vegetation, soil organic horizons and snow were measured. N-factors, the ratio of ground-surface temperatur...

The present study investigated the impact of environmental pollution, represented in soil,irrigation water and air heavy metals, on the growth and production of Egyptian clovercultivated at south Greater Cairo, Egypt. Plants were sampled through five quadrats (0.5×0.5m), distributed equally in four cultivated farms in unpolluted and polluted sites, at theharvesting time. In addition, soil, air ...

Biopolymers are viewed as effective and eco-friendly agents in soil modification. This study focuses on the wettability analysis of polyacrylamide (PAM) solutions for soil remediation. The contact angle, surface tension, and viscosity of PAM solutions were experimentally evaluated in air- and decane-biopolymer solution systems. Furthermore, a micromodel was used to investigate the pore-scale di...

[1] Historical observations indicate a shift toward shorter winters and increased average air temperatures in the midwestern United States. Furthermore, a rise in soil temperatures is likely to be enhanced under projections of increased air temperature; however, reduced snow cover during winter may lead to colder soil temperatures in the future. Cumulatively, these changes will affect cold seas...

Carbon dioxide fluxes between the soil and atmosphere were determined on the 1991 free-air carbon dioxide enrichment (FACE) experiment at the Maricopa Agricultural Center, Maricopa, Arizona. The study was conducted on drip-irrigated cotton in conjunction with other physical and physiological measurements. Fluxes were measured with a 1.6 1 closedchamber static sampling system. The main treatment...

An earlier onset of photosynthesis in spring for boreal forest trees is predicted as the climate warms, yet the importance of soil vs air temperatures for spring recovery remains to be determined. Effects of various soil- and air-temperature conditions on spring recovery of photosynthesis in Scots pine (Pinus sylvestris) seedlings were assessed under controlled environmental conditions. Using w...

The carbon isotopic composition (δ13C) of CO2 efflux (δCefflux) from soil is generally interpreted to represent the actual isotopic composition of the respiratory source (δCRs). However, soils contain a large CO2 pool in airfilled pores. This pool receives CO2 from belowground respiration and exchanges CO2 with the atmosphere (via diffusion and advection) and the soil liquid phase (via dissolut...

An understanding of gas transport in unsaturated media is important for evaluation of soil aeration or movement of O 2 from the atmosphere to the soil. Soil aeration is critical for plant root growth because roots generally cannot get enough O 2 from leaves. Evaluation of gas movement is also important for estimating transport of volatile and semivolatile organic compounds from contaminated sit...

simultaneous heat and water model (shaw) is based on the assimilation rate of melting and/or freezing of the accumulated snow as well as melting of ice in soil. the main objective of this study was to evaluate applicability of shaw model in determining maximum depth of frost penetration in soils in some typical climates of iran. to this end, the daily data of air temperature, soil temperatures ...