Increasing diffuse nitrate loading of surface waters and groundwater has emerged as a major problem in many agricultural areas of the world, resulting in contamination of drinking water resources in aquifers as well as eutrophication of freshwaters and coastal marine ecosystems. Although empirical correlations between application rates of N fertilizers to agricultural soils and nitrate contamin...

Based on the laboratory study, the effects of sodium polyacrylate (SP) was investigated at 5 rates of 0, 0.08, 0.2, 0.5, and 1%, on water retention, saturated hydraulic conductivity(Ks), infiltration characteristic and water distribution profiles of a sandy soil. The results showed that water retention and available water capacity effectively increased with increasing SP rate. The Ks and the ra...

Bimodal soils with aggregates present a complex micro-structural and volumetric behaviour. This occurs because they showcase several variables, such as mineralogical, different grain sizes structures. The objective of this paper is to develop methodology for producing simple, non-mineralogical variability controlled double porosity. In sense, using Kaolin were created obtain bimodal samples. pr...

In this study, we evaluated the efficiency of two types of biomass residues (fermentation residues from a bioethanol process, FB; brown mill residues from a papermaking process, BM) as amendments for a sandy soil. The characteristics of these residues including specific surface areas, morphologies and nutrient sorption capacity were measured. The effects of biorefinery residues on water and nut...

Sand improvements using organic agents have shown promising results. Polyacrylamide is one possible organic agent, which has been shown to influence the shear strength, stiffness, soil remediation, and erosion resistance of geomaterials. In this study, we explored the shear wave velocity (S-wave) and water retention curves of unsaturated sands containing polyacrylamide solutions. The shear wave...

in this study, a bearing capacity device is designed and fabricated to determine the load-settlement behavior of three circular footing models resting above the ground water table. capillary rise in the studied well graded sand is measured and the level of the water table is controlled at the desired heights during each bearing capacity test. moreover, shear strength parameters and soil water r...

In this study, the aim was to compare experimental and empirical methods used for estimation soil water retention under different conditions. Soil samples were chosen represent examples of heavy, medium light structures. Water curves obtained in laboratory using standard method. The van Genuchten (1980) (vG), Brooks Corey (1964) (BC) empirically. Model parameters determined by artificial neural...