Influence de l'état d'ameublissement et de la rugosité du sol des parcelles agricoles sur l'exactitude de l'altitude des points de contrôle positionnés au GPS

Agricultural soil tilth and roughness impact on the exactness of ground control points elevation surveyed by GPS. Our goal in this study is to estimate through ranges of variation, the impact of agricultural parcels soil's tilth and roughness, due to cultivation techniques, on the exactness of ground control points elevation surveyed by RTK (Real Time Kinematic) GPS (Global Positioning System). So, 16 point's elevations which were located each 100 mm on a transect have been surveyed first by using a Total Station (TS), and then a RTK GPS in 2 parcels (3 transects per parcel). Cultivation techniques on those parcels were different. The parcel 1 was tilled, and the soil of parcel 2 was prepared for cereal cropping. Then, the analysis of variance has been applied on the differences of TS and RTK GPS elevations data to estimate the confidence interval of ground control points elevation due to soil tilth, whereas the times series statistical method has been applied on elevation data to estimate the confidence interval due to soil roughness. The confidence intervals of points elevation are estimated being [51 mm; 57 mm], [-4 mm; 4 mm] for parcel 1, and [97 mm; 113 mm], [-35 mm; 23 mm], for parcel 2. Results show that ground control point's elevations exactness is influenced by soil tilth and soil roughness. In conclusion, we can admit that soil tilth and soil roughness have significant impact on the exactness of ground control points located on agricultural parcels. This impact must be considered in Digital Elevation Model (DEM) errors evaluation of agricultural watershed

Etude méthodologique relative au traitement de la zone agricole dans le cadre de la révision des plans de secteur

info:eu-repo/semantics/publishe

UTILISATION DES RADIOLANTHANIDES DANS LA DÉTERMINATION DU TRANSIT GASTRO-INTESTINAL CHEZ LES PETITS RUMINANTS COMPARAISON DES TECHXIQUES DIRECTE (ABATTAGE) ET INDIRECTE

International audienc

Conventional Versus Alternative Pig Production Assessed By Multicriteria Decision Analysis

Differentiated quality and respect for the environment seem to be linked implicitly, but there is no demonstration of this concept for pig production. Pig production takes on different forms. Conventional pig production occurs side by side with some productions of “differentiated qualities” that are encouraged by the European Union as well as by nations. At the same time, the EU and nations are imposing environmental limitations concerning, for instance, the management of nitrogen and respect for neighbours. Here, we compared environmental impacts of 3 types of production: conventional production, organic production and free-range production. We took into account the process performances of 21 farms in the Walloon Region, Belgium. We compared the global process performances by multicriteria analysis. A jury of 16 experts was questioned to assign a relative importance to the emissions of ammonia, greenhouse gases, molecular nitrogen, odour and nitrogen to effluents. We found that the highest weighting was assigned to the N content of effluents, then to odour diffusion, the emission of ammonia, the emissions of greenhouse gas and finally, the emission of molecular nitrogen got a weak weighting. Our results showed that the relative ordering obtained was: (1) free-range production, (2) organic production and (3) conventional production. Nevertheless, within every sample a significant variability in the performances was observed. The same method applied within every sample enabled the creation of sub-groups. After reordering, we found that the most effective farms of every system of production were classified as top of the class. Thus, our original approach showed that on average the production of differentiated qualities was more environmentally effective than the conventional production. However, the variability of the performances within a system of production was high and it was quite possible for the conventional farms to reach results comparable with those of the best organic and free-range operations