Soil losses due to potato harvesting at the regional scale in Belgium

During harvesting of crops, such as sugar beet, potatoes and chicory roots, considerable quantities of soil, consisting of adhering soil, soil clods and stones, are exported from cropland. This soil erosion process is called soil loss due to crop harvesting (SLCH). This study aimed to assess the variability in soil losses caused by potato (Solanum tuberosum L.) harvesting in Belgium and to investigate the role of weather conditions prior to the harvest and regional differences in soil texture on SLCH variability. To meet these objectives, more than 1000 soil tare data measured at a potato-processing factory during the harvesting seasons of 1999, 2000 and 2001 were analysed. Soil loss was on an average 2.2 t ha^-1 per harvest but could be as large as 45 t ha ^-1 per harvest. The average soil losses per municipality were positively and exponentially related to the average content of soil particles <16 μm. This relationship was in close agreement with a previous field study on SLCH for potatoes in Belgium and could explain why measured soil loss values from a German study were larger than SLCH values for potatoes measured in Belgium. Weather conditions prior to harvest played only a minor role for SLCH variability. As a consequence, SLCH for potatoes harvested mechanically is more variable in space than in time.