abstract saturated water content is one of the important parameters which its measurement is necessary in estimation of soil water retention and unsaturated hydraulic conductivity curves. in several researches, saturated water content is assumed to be equal to soil total porosity. in some others, its value is estimated by pedotransfer functions using readily available parameters, such as bulk d...

Shear strength of aggregates and the bulk soil matrix in two Haploxeroll of central Chile was assessed in order to determine: (1) the effect of previous tillage on shear parameters between aggregates and in the soil matrix and (2) the effects of structure development on differences between dry-wet mechanical parameters. Undisturbed soil cylinders and single aggregates (0-10 cm layer) were colle...

A study was conducted to determine the impacts of soil disturbance and compaction on soil physical properties and tree growth and the effectiveness of tillage in maintaining or enhancing site productivity for intensively managed Pinus kesiya Royle ex Gordon sites in Dedza, Malawi. The results indicate that about fifty-two percent of the area of compacted plots was affected by the vehicular traf...

Two series of displacement experiments with isoproturon and metribuzin herbicides were performed on two undisturbed grassed filter strip soil cores, under unsaturated steady-state flow conditions. Several rainfall intensities (0.070, 0.147, 0.161, 0.308 and 0.326 cm h(-1)) were used. A water tracer (bromide) was simultaneously injected in each displacement experiment. A descriptive analysis of ...

Cut slopes are frequently generated by construction work in hilly areas, and artificial soil is often sprayed onto them to promote ecological rehabilitation. The artificial soil properties are very important for effective management of the slopes. This paper uses fractal and moment methods to characterize soil particle size distribution (PSD) and aggregates composition. The fractal dimension (D...

One of the most important issues in ground based wood extraction in forestry is to minimize the soil damage caused by heavy forestry machines. Generally, harvesting effects include changes in vegetation nutrient availability, soil microclimate/structure and litter quantity/ quality. Several studies were carried out on the impacts of heavy machines on the soil. However, only few studies took int...

The differences in rhizosphere nitrification activities between high- and low- fertility soils appear to be related to differences in dissolved oxygen concentrations in the soil, implying a relationship to differences in the radial oxygen loss (ROL) of rice roots in these soils. A miniaturised Clark-type oxygen microelectrode system was used to determine rice root ROL and the rhizosphere oxygen...

Introduction Soil organisms facilitate key ecosystem processes such as nutrient cycling and organic matter decomposition, and also influence soil porosity and water infiltration through the production of bacterial polymers and fungal hyphae that hold soil particles together to form aggregates [1, 2]. Rhizosphere microorganisms can greatly influence the ability of a plant to acquire macroand mic...

A soil-water characteristic (SWC) curve describes the amount of water retained in a soil (expressed as mass or volume water content, m or v) under equilibrium at a given matric potential. An SWC is an important hydraulic property, related to size and connectedness of pore spaces, hence strongly affected by soil texture and structure, and by other constituents, including organic matter. Modeling...

Many techniques have been proposed in recent years for in situ soil characterization, and among them, acoustic methods have been revealed to be particularly promising. These methods are based on measurements of the propagation velocities of seismic, sonic, and ultrasonic waves. However, in granular and porous mediums, velocities depend on the state of the saturation of the soil in a complex and...