The design and operation of supplementary irrigation schemes are dependent upon an accurate estimation of the "total available moisture" in the soil. This has been defined as the amount of water held between the limits of field capacity and wilting point in the effective rooting depth of the crop. Under irrigated conditions the effective rooting depth is that depth of soil from which the crop c...

At radar frequencies below 2 GHz, the mismatch between the 5 to 15 cm sensing depth of classical time domain reflectometry (TDR) probe soil moisture measurements and the radar penetration depth can easily lead to unreliable in situ data. Accurate quantitative measurements of soil water contents at various depths by classical methods are cumbersome and usually highly invasive. We propose an impr...

The genus Heterodera consists of 80 valid species which are distributed all over the world and they range from mono to polyphagous (Subotin et al., 2010). Several species are considered economically important (or quarantine), including H. humuli Filipjev, 1934. Previous studies on H. humuli or H. humuli as a vector of plant viruses were focused on its geographical distribution, biology, life cy...

The crack developing depth is a key problem to slope stability of the expansive soil and its project governance and the crack appears under the roles of dry-wet cycle and gradually develops. It is believed from the analysis that, because of its own cohesion, the expansive soil will have a certain amount of deformation under pulling stress but without cracks. The soil body will crack only when t...

Relatively little is known about the microbial communities adapted to soil environments contaminated with aged complex hydrocarbon mixtures, especially in the subsurface soil layers. In this work we studied the microbial communities in two different soil profiles down to the depth of 7 m which originated from a 30-year-old site contaminated with petroleum hydrocarbons (PHCs) and from a clean si...

Soil compaction in the form of a hardpan layer restricts root growth and reduces crop yield throughout the Southeastern United States. However, the depth of this compacted soil layer varies significantly over landscapes. A sampling procedure was developed and evaluated to determine the depth of the hardpan layer in upland soils of Grenada silt loam soil type in this region. Cone index profiles ...

simultaneous heat and water model (shaw) is based on the assimilation rate of melting and/or freezing of the accumulated snow as well as melting of ice in soil. the main objective of this study was to evaluate applicability of shaw model in determining maximum depth of frost penetration in soils in some typical climates of iran. to this end, the daily data of air temperature, soil temperatures ...

There is convincing evidence for the benefits of deep rooting, especially in relation to drought resistance (Lopes & Reynolds, 2010; Uga et al., 2013). Modelling has shown that greater root depth allows increased water uptake and higher yields (Lilley & Kirkegaard, 2011). Deep rooting is thought to be improved by combinations of traits that confer steeper growth and an ability to penetrate stro...

Elevated atmospheric carbon dioxide concentrations [CO2] is projected to increase forest production, which could increase ecosystem carbon (C) storage. This study contributes to our broad goal of understanding the causes and consequences of increased fine-root production and mortality under elevated [CO2] by examining potential gross nitrogen (N) cycling rates throughout the soil profile. Our s...

in forest harvesting, there is an ongoing trend to increase constantly the size, power and load of logging machines. this may cause soil degradation in forest ecosystems as the passes of these machines modify important soil structural characteristics. the present study was conducted to examine impact of skidding traffic, trail slope, traffic frequency, and soil depth on bulk density and soil co...