to study the effects of soil amendments on physical and hydraulic properties of a saline-sodic sandy clay loam soil, a field experiment was carried out as a complete block design with three replications. the treatments in this research consisted of control (b), 10 ton ha-1 gypsum (g), 10 ton ha-1 urban solid compost (c), three levels of vinyl alcohol acrylic acid (s1= 0.05%, s2= 0.1%, s3= 0.2%)...

soil quality is a necessary indicator of land management. different indices are applied to evaluate farming systems, soil types and land uses based on soil quality. the slope of retention curve at its inflection point has been defined as soil physical quality index (si) but the relationships between si and penetration resistance (pr), the least limiting water range (llwr), and available water c...

abstract water retention curve (wrc) is a fundamental property of soil. it is used to evaluate available water, permeability, drainage and movement of solutes. despite numerous studies on wrc of soils abroad, no local study has been carried out on charmahal-va-bakhtiari soils. the objective of this study was to compare the quality of fitting of several wrc models to lordegan soils and to select...

In order to obtain the soil water retention curve of an unsaturated soil which is defined as the relationship between water content and suction, extensive laboratory tests are essential. These laboratory tests are usually costly and time consuming. Moreover, for most practical problems, it has been found that approximate unsaturated soil properties are adequate for analysis. Thus, empirical pro...

Many studies of water flow and solute transport in the vadose zone require estimates of the unsaturated soil hydraulic properties, including the soil water retention curve ~WRC! describing the relationship between soil suction and water content. An artificial neural network ~ANN! approach was developed to describe the WRC using observed data from several soils. The ANN approach was found to pro...

Erosion changes soil properties, especially physical properties, mainly because it removes surface soil rich in organic materials and exposes lower soil layers. In 1988, a study was established to determine the effects of soil erosion and long-term manure applications on selected soil phys­ ical properties and corn (Zea mays L.) production. After 10 years of an­ nual manure applications, soil c...

Soil water retention parameters are critical to quantify flow and solute transport in vadose zone, while the presence of rock fragments remarkably increases their variability. Therefore a novel method for determining water retention parameters of soil-gravel mixtures is required. The procedure to generate such a model is based firstly on the determination of the quantitative relationship betwee...

The scaling theory approach has been widely used as an effective method to describe the variation of soil hydraulic properties. In conventional scaling, reference retention curves and scaling factors are determined from minimization of residuals. Most previous studies have shown that scaling factors are lognormally distributed. In this study, we derived physically based scaling factors, assumin...

application of superabsorbent material is one of the new methods for moisture storage in the soil. this research was performed in the khajeh research station on the basis of randomized complete block design with three replications in the plots with dimension of 4×5 meter for investigate the effect of different amounts of pumice on water retention capacity in the soil, growth and of spring saffl...