an experiment involving erosion simulation was conducted at the soil and water con-servation research center of the university of tehran. a split-factorial plot with four replications was designed. five soil desurfacing treatments of blank, 5, 10, 15, and 20 cm of soil surface removal (e0, e5, e10, e15, and e20) were carried out, respectively. fertilizer treatments were 0, 65, and 130 kg ha-1 o...

Lianas (woody vines) are particularly abundant in tropical forests, and their abundance is increasing in the neotropics. Lianas can compete intensely with trees for above- and belowground resources, including water. As tropical forests experience longer and more intense dry seasons, competition for water is likely to intensify. However, we lack an understanding of how liana abundance affects so...

Nonsorted circles are relatively barren patterned-ground features common in most arctic tundra regions. We studied how vegetation changes on nonsorted circles might affect cryogenic processes, which is of relevance as arctic vegetation responds to climate change. Twenty-eight circles at a moist nonacidic tundra site in northern Alaska received one of four treatments: (a) vegetation removal; (b)...

Soil treatment of wastewater has the potential to achieve high purification efficiency, yet the understanding and predictability of purification with respect to removal of viruses and other pathogens is limited. Research has been completed to quantify the removal of virus and bacteria through the use of microbial surrogates and conservative tracers during controlled experiments with three-dimen...

Corn (Zea mays L.) stover is a primary biofuel feedstock and its expanded use could help reduce reliance on fossil fuels and net CO2 emissions. Excessive stover removal may, however, negatively impact near-surface soil properties within a short period after removal. We assessed changes in soil crust strength, bulk density (rb), and water content over a 1-yr period following a systematic removal...

Bioenergy cropping systems have been proposed as a way to enhance United States energy security. However, research on soil physical properties, soil-surface CO2 effluxes, and soil drainage dynamics in such systems is needed to ensure environmental sustainability in the field. The objective of our research was to evaluate soil physical properties and conditions as well as soil-surface CO2 efflux...

Carbon nanotubes are often modified to be stable in the aqueous phase by adding extensive hydrophilic surface functional groups. The stability of such CNTs in water with soil or sediment is one critical factor controlling their environmental fate. We conducted a series of experiments to quantitatively assess the association between water dispersed multi-walled carbon nanotubes (MWCNTs) and thre...