V. Souchere | AgroParisTech - Academia.edu (original) (raw)

Papers by V. Souchere

Soil erosion leads to important environmental problems (e.g. muddy floods, reservoir sedimentatio... more Soil erosion leads to important environmental problems (e.g. muddy floods, reservoir sedimentation) in cultivated areas of the European loess belt. This study aimed to quantify erosion and to determine the impact of rainfall seasonality and land use change on soil erosion over the last 40 years in a 94-ha cultivated catchment of Normandy (France). To this end, scenarios representative of

Agriculture, Ecosystems & Environment, 2010

Ecological Modelling, 2015

ABSTRACT Cultivar resistance plays a major role in current disease management strategies, but its... more ABSTRACT Cultivar resistance plays a major role in current disease management strategies, but its efficacy is usually short-lived unless resistance deployment strategies to ensure resistance durability can be designed. Using a spatially explicit model, we evaluated cropping system mosaics that were designed by stakeholders involved in field agronomic practices to manage phoma stem canker of winter oilseed rape. We simulated pathogen population adaptation to a newly introduced major resistance gene (RlmX) to estimate the durability of the resistance under various scenarios of cropping system mosaics within a small region. Our objective was first to find descriptors of agricultural landscape that are relevant for resistance management and then to study the relationship between cropping practices applied in nearby fields and the genetic structure of the pathogen population in fields cropped with RlmX-cultivars. Key cropping practices were characterized with different metrics for several buffer sizes (100–2000 m) around target fields; and these indicators were used in linear models to predict pathogen evolution. Indicators describing local cultivar composition were very informative; adding information on tillage, but not nitrogen fertilization or fungicide treatment, could marginally increase the goodness of fit. The effects of cropping practices on resistance durability could be shown when the landscape was characterized within 500 m around RlmX-fields. We conclude that, in order to study and ultimately design landscapes promoting resistance durability against phoma stem canker, it is sufficient to take into account a relatively small portion of the landscape around RlmX-cultivars, focusing on cultivar choice and tillage practices of RlmX cultivated fields.

Boardman/Soil Erosion in Europe, 2006

European Journal of Agronomy, 2015

Soil and Tillage Research, 2002

Journal of Hydrology, 1998

In areas of intensive agriculture, e.g. ‘Pays de Caux’ in France, which was the study area, field... more In areas of intensive agriculture, e.g. ‘Pays de Caux’ in France, which was the study area, field observations have shown that runoff directions were modified by agricultural activities. In order to account for factors responsible for modifications of the runoff direction (roughness, tillage direction and agricultural patterns, e.g. dead furrow or dirt tracks), we constructed a discriminant function based on field observations. This function enables us to decide whether flow direction for slopes of up to 15% was imposed by slope direction or tillage direction. It can be applied to any location, provided there are known roughness, known slope intensity, known aspect and known tillage azimuth.In order to examine the effects of these agricultural activities at the catchment scale, we compared two models by analysing the same hydrological variables: the area contributing to runoff and the flow network. The first model (Topo) was built according to the runoff direction derived from a Digital Elevation Model (DEM). The second model (Tillage) was constructed by combining information from the DEM, and information from rules based on field observations or resulting from statistical analysis.For 23 basic catchments, the result of the comparison between the two models (Topo and Tillage) showed that a major part of the catchments and the drainage network was affected by modifications related to the introduction of man-made agricultural factors. For example, for 20 of 23 catchments, the runoff flows over more than 50% of the surface of such areas were produced along the direction imposed by tillage. The introduction of tillage effect brings about modifications of both the shape and size of catchments.

Journal of Hydrology, 2012

... 2. Theoretical relationship between spatial scale and published mean sediment concentration d... more ... 2. Theoretical relationship between spatial scale and published mean sediment concentration derived from erosion rates in agricultural temperate areas of North-western Europe (over the loess belt), for arable lands with slopes between 2 and 5% ( (1) Fox and Bryan, 1999-(2 ...

International Journal of Sustainable Development, 2004

Earth Surface Processes and Landforms, 2002