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

Abstract

This paper investigates soil stratigraphy of lynchets in sloping lands in eastern Belgium, and rates of their development by comparison to tillage translocation by non-mechanised agriculture. In Belgium, detailed topographical surveys and augerings were carried out at three sites that were under cropland till 1900–1950. Rates and diffusion constants of current non-mechanised tillage erosion were monitored in Ethiopia using tracers, and by precise surveys of tillage steps of known ages. The lynchets in Belgium consist of colluvium that was removed at the upper border of previously farmed plots. Repeated tillage with animal drawn implements results in soil translocation fluxes to the lower plot borders in the order of 11 to 91kgm−1year−1 (for slope gradients between 0.03 and 0.35mm−1). The studied lynchets in eastern Belgium would have required cropping agriculture for a total of 217–585years on steep, and 1037–1867years on gentle slopes. The establishment of lynchets hence took place without any deliberate action of digging, but due to repeated tillage, even with simple implements, and water erosion. Calculated time spans of tillage indicate that some parts of the study area had already been under cultivation during the Gallo-Roman period, others since the Middle Ages.