ground skidding on skid trails affects the physical properties of soil. the objective of this study was to evaluate changes in soil physical properties on skid trails formed due to traffic of metal-tracked skidders with regard to soil bulk density, total porosity, water content and penetration resistance. the studies were implemented on two levels of slope – 20% (sc2) – and three levels of traf...

Displacement finite element analysis is performed for a cone-penetration test in cohesionless soils. By modelling finite strain in the soil and large scale sliding at the penetrometer–soil interface, a more realistic penetration process is simulated in which the penetrometer is assumed to be rigid and the soil is assumed to be an elastic-perfect-plastic continuum obeying the Mohr–Coulomb criter...

Soil compaction is an important physical limiting factor for the root growth and plant emergence and is one of the major causes for reduced crop yield worldwide. The objective of this study was to generate 2D/3D soil compaction maps for different depth layers of the soil. To do so, a soil penetrometer was designed, which was mounted on the three-point hitch of an agricultural tractor, consistin...

Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resist...

Frameworks for estimating soil properties from CPT penetration resistances must account for the effects of overburden stress on both the penetration resistance and the soil property of interest, including how such effects vary with soil type. For example, common procedures for estimating the liquefaction resistance of sands include functional terms that account for the effect of overburden stre...

The root cap assists the passage of the root through soil by means of its slimy mucilage secretion and by the sloughing of its outer cells. The root penetration resistance of decapped primary roots of maize (Zea mays L. cv. Mephisto) was compared with that of intact roots in loose (dry bulk density 1.0 g cm-3; penetration resistance 0.06 MPa) and compact soil (1.4 g cm-3; penetration resistance...

development of sensors to detect the location and depth of hard pans in real time is a major restriction on the application of site specific crop management (sscm). in this study, a soil compaction profile sensor equipped with four horizontal operating penetro-meters for on-the-go sensing and mapping of the location and intensity of hard pans arti-ficially formed in a soil bin was developed and...

Loamy sand soils of the southeastern USA Coastal Plains often have poor physical properties because they contain cemented subsurface hard layers that restrict root development and yield. Their physical properties can be improved by adding amendments. Polyacrylamide (PAM) amendments and/or organic matter (OM) in the form of ground wheat (Triticum aestivum L.) stubble or pecan (Carya illinoensis)...

Mycorrhizal soybean (Glycine max L. Merr. var. Harosoy-63) plants have lower resistances to water transport than nonmy-corrhizal plants after 4.5 weeks of growth. Although resistances of whole plants differ by 40%, there were no differences in the resistances of stems plus leaves, indicating that the major effect of the mycorrhizae was to reduce the resistance of the roots. Since the fungitoxic...