A practical model of the soil structure dynamics in ploughed ®elds can be a powerful aid to farmers attempting to optimise their management practices. This paper describes a compartmental model that simulates the changes over several years in an indicator of the effects of cropping systems on soil structure. This indicator, the proportion of severely compacted clods in the ploughed layer, was m...

ated with soil type, vadose zone flow and transport processes are also affected by such external factors as tillage Vadose zone flow and transport processes are known to be strongly practices. For example, Petersen et al. (1999, 2001) affected by both soil structure and soil texture. We conducted a field experiment to explore the impact of heterogeneity in soil structure showed that surface til...

In Central Aragón (NE Spain), where strong and dry winds are frequent all year round, fallow lands are susceptible to wind erosion due to insufficient crop residues on the surface and loose, finely divided soils by multiple tillage operations. Effects of conventional tillage (CT — mouldboard ploughing followed by a compacting roller) and reduced tillage (RT — chisel ploughing) on soil surface p...

Soil concentrations and degradation rates of methyl isothio-cyanate (MITC), chloropicrin (CP), 1,3-dichloropropene (1,3-D), and dimethyl disulfide (DMDS) were determined under fumigant application scenarios representative of commercial raised bed, plastic mulched vegetable production systems. Five days after application, 1,3-D, MITC, and CP were detected at concentrations up to 3.52, 0.72, and ...

The estimate of soil fertility, namely water and nutrient availability, biological activity, is usually made considering as being uniform in the reference layer. potential fertility thus estimated for homogeneous volumes. However, both profile its horizons are often not many characteristics properties. rooting volume, particular, can be limited by presence obstacles, such bedrock, cemented laye...

The objective of this paper is to present the contribution of a new dielectric constant characterisation for the modelling of radar backscattering behaviour. Our analysis is based on a large number of radar measurements acquired during different experimental campaigns (Orgeval'94, Pays de Caux'98, 99). We propose a dielectric constant model, based on the combination of contributions from both s...

this study was conducted to investigate the spatial variability of model parameters of soil shrinkage curve in cherlgerd district, chaharmahal-va-bakhtiari province. ninety nine locations were selected and soil clods were collected from the 0-10 cm layer and brought to the laboratory. soil shrinkage curve was measured, according to archimedes's principle, by covering the undisturbed clods ...

Dermatoscopic features of spiradenoma—a benign adnexal neoplasm—have not been described. We present a case of spiradenoma occurring on the occipital scalp (Figure 1A, 1B) that showed a structureless pattern and blue clods on dermatoscopy. The vascular pattern of serpentine, branched vessels (Figure 2) in combination with blue clods suggest a basal cell carcinoma (BCC) [1]. However, the blue clo...

Soil compaction has been recognised as the greatest problem in terms of damage to Australia's soil resource. Compaction by tractor and harvester tyres, related to traf®cking of wet soil, is one source of the problem. In this paper an array of soil properties was measured before and immediately after the application of a known compaction force to a wet Vertisol. A local grain harvester was used ...

Separating clods from potato tubers is one of the most challenging jobs in a potato harvester. Discriminating between potato tubers and clods is the first step in developing an automatic separation system on potato harvesters. In this study, an acoustic-based intelligent system was developed for high speed discriminating between potato tubers and clods. About 500 kg mixture of potato tubers and...