Classification and mapping of anthropogenic landforms on cultivated hillslopes using DEMs and soil thickness data — Example from the SW Parisian Basin, France

Abstract

Macaire. Classification and mapping of anthropogenic landforms on cultivated hillslopes using DEMs and soil thickness data -Example from the SW Parisian Basin, France. Geomorphology, Elsevier, 2011Elsevier, , 135 (1-2), pp.8-20. 10.1016Elsevier, /j.geomorph.2011 Classification and mapping of anthropogenic landforms on cultivated hillslopes using DEMs and soil thickness data -Example from the SW Parisian Basin, France AbstractThis study focuses on linear anthropogenic landforms of decametric width on cultivated hillslopes and their relations to soil thickness variability. The 16 ha study area shows a rolling topography supported by Cretaceous chalk of the SW Parisian Basin, France. Two types of landforms were identified: lynchets, similar to those described as soil terraces occurring on downslope field parts in other contexts, and undulations, linear, convex landforms that cut across fields. Accurate DEM construction and a detailed soil thickness survey were performed all over the study area. Soil samples were classified considering their location on specific types of anthropogenic landforms. The Classification Tree (CT) method was applied to assess whether lynchets and undulations can be discriminated through morphometric attributes (slope, curvature, profile curvature and planform curvature) and soil thickness (CT soil ) or through morphometric attributes only (CT topo ). The CT application establishes predictive classification models to map the spatial distribution of lynchets and undulations over the whole study area. The validation results of the CT soil and CT topo applications show model efficiencies of 83% and 67%, respectively. Both models performed well for lynchets. Errors arise mainly from difficulties in unequivocally discriminating gently convex undulations and undifferentiated surfaces, especially when soil thickness is not accounted for. Mean values of soil thickness are 1.08, 0.62 and 0.45 m in lynchets, undulations and undifferentiated areas, respectively. The general shape of the thickened soil is characteristic to each type of anthropogenic landform. Multi-temporal mapping of field border networks shows that undulations are linked to borders that were removed during the latest land consolidation. Lynchets are associated with current field borders. Lynchets and undulations, which cover 39% of the study area, define topographic indicators of human-induced soil accumulations. The method involves perspectives for efficiently mapping and quantifying the anthropogenically modified spatial variability of soil thickness on agricultural hillsides.

Solum depth spatial prediction comparing conventional with knowledge-based digital soil mapping approaches

“…Solum depth is strongly linked to landscape characteristics and it is important for soil mapping (Chartin et al, 2011), and land use planning and management.…”

Soil depth estimation through soil-landscape modelling using regression kriging in a Himalayan terrain

“…Geostatistical models such as ordinary kriging (OK), regression kriging (RK), cokriging (COK), linear-nonlinear regression and few other multivariate methods were successfully tested in different landscapes for the soil depth estimation (Gessler et al 1995, Bourennane et al 2000, Tsai et al 2001, Henglet al 2004, Ziadat 2005, Kuriakose et al 2009, Chartin et al 2011. Topographic attributes derived from a digital elevation model (DEM) were used in these geostatistical models for the quantitative estimation of soil properties and their distribution (Gessler et al 1995, Boer et al 1996, Florinsky et al 2002, Thompson et al 2006, Pelletier and Rasmussen 2009, Vanwalleghem et al 2010, Mehnatkesh et al 2013).…”

“…Long-term human activities such as cultivation and afforestation have a significant role in soil redistribution (Chartin et al 2011). Kuriakose et al (2009) compared different statistical methods to estimate soil thickness in the Western Ghats of Kerala state in India and found that RK is the best method for prediction, and land use was identified as the key explanatory variable for the soil depth estimation.…”

Lynchets in eastern Belgium — a geomorphic feature resulting from non-mechanised crop farming

“…As observed in Ethiopia, tillage erosion by simple tools, in addition to sediment transport due to water erosion, can lead to fast soil accumulation in the lynchets (Chartin et al, 2011;De Alba et al, 2004). As the rate of tillage erosion is independent from slope length, imposing lynchets can also develop on narrow parcels, established along the contour, as shown elsewhere (Patro et al, 2008).…”

“…Occurrence in relation to farm-and woodland boundaries that are located along the contour (Szabó, 2010) and to land cultivation has been established rapidly (Aufrère, 1927;Raistrick and Chapman, 1929). Whereas for most soil scientists and geomorphologists (Chartin et al, 2011;Dabney et al, 1999;Ozer, 1969;Patro et al, 2008) there is no doubt that lynchets have grown as a consequence of tillage and water erosion, speculations on deliberate digging of terraces regularly surface (Fénelon, 1956;Fénelon, 1963;Raistrick and Chapman, 1929;Van Westreenen, 2008).…”