Dans les milieux renseigner la présence de résidus de pesticides

National audienc

Les réseaux de surveillance de la qualité des sols en France et en Europe, vers l'intégration de paramètres biologiques ?

National audienc

Fonctionnement et gestion raisonnée de l'écosystème forestier landais. Rapport final

* INRA Ephyse Pierroton (FRA) Diffusion du document : INRA Ephyse Pierroton (FRA

Un hommage à Marcel Jamagne

National audienc

Analysis of the Representativeness of land use in France by the French Soil Monitoring Network

International audienceSoil monitoring networks are developed at European scale for soil protection and sustainable management objectives, according diverse sampling strategies. French Soil Monitoring network (RMQS) is based on a systematic 16 * 16 km grid, counting 2200 plots and covering various land use (from arable land to natural land) and various soil types. At the beginning of the programm, a first study enables to establish the minimal density required for a systematic grid-based network and offering an adequate compromise in time and cost for the settlement. The first sampling campaign has been carried out from 2001 to 2009. We need now to guarantee validity and extrapolation of our results at the national level by checking the representativeness of the land use distribution of monitoring sites regards of the whole French land cover. We propose in this study to compare the distribution of the land use for RMQS sites with land use data from two sources of land use data : 1) Corine Land Cover database as exhaustive available land use information for France and 2) national agricultural statistics, providing detailed and annual data concerning crops, grassland and and woodland. The study aims also to detect and interpret local differences between these distribution

Variabilité intraparcellaire de quelques propriétés des sols sableux des landes de Gascogne (France). Conséquences sur la stratégie d'échantillonnage agronomique

National audienc

The soil quality monitoring network for French soils (RMQS): state of progress and first results

International audienc

Optimizing pedotransfer functions for estimating soil bulk density using boosted regression trees

International audiencePedotransfer functions (PTFs) are used to estimate certain soil properties that are difficult and costly to measure front others more easily available. Bulk density is one important soil property. Although nor requiring complex analysis, its measurement remains time consuming and is lacking in many soil surveys. For several decades, PTFs have been developed for predicting soil bulk density. Most of these PTFs are suited only for specific agro-pedo-climatic conditions, however, and can be applied only within a limited geographic area. In this study, we derived and experimented with two new PTFs based on a multiple additive regression trees (MART) method, and assessed their performance compared with existing PTFs when applied to a country-level soil database, the Reseau de Mesures de la Qualite des Sols (RMQS) survey network. This database was designed to include the major soil types and land uses in France. The first proposed PTF (Model m) involves only three predictors typically found in the existing PTFs for bulk density (C content and texture) and the second one (Model M) includes eight easily accessible quantitative and qualitative predictors (e.g., soil taxon). Both models significantly outperformed existing PTFs. Without arbitrarily partitioning the data set before fitting the model, the m and M MART models yielded R-2 values of 0.83 and 0.94, respectively. The predictive quality on independent data, assessed using cross-validation, was also improved compared with published PTFs, with R-2 reaching 0.62 and 0.66 and root mean square prediction errors of 0.123 and 0.117 Mg m(-3) for the two MAPT models