The relation between the sodium adsorption ratio (SAR) and pHc derived here predicts SAR of the drainage water (SARdw) better than existing empirical equations. Inaccuracies in SAR estimates from the new relationship can be anticipated by the extent to which the derived conditions are valid. Empirical equations provide no understanding of why they are sometimes inaccurate. Due to the relative i...

subsurface drainage systems are used to control the depth of the water table and to reduce or prevent soil salinity. water flow in these systems is described by the boussinesq equation, and the advection-dispersion equation coupled with the boussinesq equation is used to study the solute transport. the objective of this study was to propose a finite difference solution of the advection-dispersi...

This is the second of two papers that elaborate on an integrated drainage network analysis system (IDNAS) for agricultural drainage management. In the ®rst paper, the system components, functions and implementation were presented. This paper focuses on the system applications to agricultural drainage management, particularly on the acid drainage problems in an estuarine acid sulfate soil ̄oodpl...

The goal of cathodic protection is to prevent corrosion by maintaining buried pipelines at a constant potential with respect to the surrounding soil. In practice, however, the implementation is very complicated since many factors can contribute to the current flowing off the pipe. Design requires characterization of the parameters impacting the corrosion process, such as soil resistivity, size ...

the system dynamics technique is an object-oriented approach that studies and manages complex feedback systems. its merits include the friendly and easy development and improvement of a model. it is also used as a decision tool for engineering problems. in this paper, the system dynamics technique was used to simulate the performance of a subsurface drainage system in an unsteady state. the mod...

Assessment of soil erosion is expensive and intensively long exercise. A number of parametric models have been developed to forecast soil erosion at drainage basins, yet Universal Soil Loss Equation, popularly known as USLE model is most widely used empirical formula for estimating annual soil loss from agricultural basins. With the advance of Remote Sensing technique it becomes possible to mea...

in this research, the appropriateness of drainmod-n model was evaluated for the simulation of nitrate transport with subsurface drainage in paddy fields. during a canola growing season from november 2011 to april 2012, the nitrate concentration of drainage water and soil saturation extracts of two depths of 30 and 60 cm was measured in consolidated paddy fields of sari agricultural sciences and...

We assessed the vertical growth and mycorrhizal infection of woody plant roots on a closed landfill, using tree and shrub clusters that had been previously installed in patches of increasing size to establish protocols for woodland restoration. The density of the fine roots of shrubs, which had poor-to-moderate mycorrhizal infection, decreased strongly with increasing depth. Oak ( Quercus ) see...

Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada (RMRB) Department of Biological Sciences, University of Cape Town, 7701 Rondebosch, Republic of South Africa (RMRB, DSJ, CTH, RMB) Department of Biology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada (RMB) Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria...

The effects of ionic strength of the permeating fluid on the clogging of soil filters and drainage layers are addressed using both experimental and modeling investigations. In the experimental phase, a sandy soil representative of soil filters was permeated with pore fluids containing kaolinite particles. The ionic strength of the solutions was changed using different concentrations of NaOH and...