Septic tank effluent is inherently high in sodium ions relative to divalent cations (high sodium adsorption ratio). The disposal of septic tank effluent to the soil will cause the sodium ions to disperse the clay colloids, resulting in a physical blocking of the soil pores. Hydraulic conductivity will be reduced and the effluent will fail to dissipate into the soil profile. In designing the dis...

Steady-state and transient one-dimensional unsaturated flow in vertically stratified porous media are examined. Saturated hydraulic conductivity and the alpha parameter of the exponential hydraulic conductivity function were assumed to vary from soil layer to soil layer. The use of effective unsaturated hydraulic conductivity to compute matric potential in the soil profile is demonstrated. Resu...

Characterization of soil water content (SWC) profiles at catchment scale has profound implications for understanding hydrological processes of the terrestrial water cycle, thereby contributing to sustainable water management and ecological restoration in arid and semi-arid regions. This study described the vertical profiles of SWC at the small catchment scale on the hilly and gully Loess Platea...

The conversion of virgin desert into oasis farmland creates two contrasting types of land-cover. During oasis formation with irrigation and fertilizer application, however, the changes in the soil microbial population, which play critical roles in the ecosystem, remain poorly understood. We applied high-throughput pyrosequencing to investigate bacterial and archaeal communities throughout the p...

The diversity of Ochrobactrum anthropi, Ochrobactrum intermedium, Ochrobactrum tritici and Ochrobactrum grignonense in agricultural soil and on the wheat rhizoplane was investigated. O. anthropi was isolated both from soil and from the rhizoplane, O. intermedium and grignonense only from bulk soil, and O. tritici only from the wheat rhizoplane. On the genetic level, the immunotrapped isolates a...

Subsurface-tile drainage is designed to remove gravitational water and soluble salts from the soil-root zone. However, soil swelling, as influenced by soil Na and electrical conductivity (EC), will reduce saturated hydraulic conductivity. The objective of this research was to determine the influence of Na and EC on the amount of water retained at field capacity (33 kPa), in northern Great Plain...

introduction: nitrogen (n) is one of the most important growth-limiting nutrients for dryland wheat. mineral nitrogen or ammonium (nh4+) and nitrate (no3−) are two common forms of inorganic nitrogen that can serve as limiting factors for plant growth. nitrogen fertilization in dryland area can increase the use of soil moisture, and improve wheat yields to some extent. many researchers have been...

At a watershed scale, sediments and soil weathering exerts a control on solid and dissolved transport of trace elements in surface waters and it can be considered as a source of pollution. The studied subwatershed (1.5 km) was located on an As-geochemical anomaly. The studied soil profile showed a significant decrease of As content from 1500 mg kg in the 135– 165 cm deepest soil layer to 385 mg...