Soil loss due to crop harvesting: significance and determining factors.

Water, wind and tillage erosion are well-studied soil erosion processes. However, there is another process of soil erosion that is rarely considered in the field of earth sciences but one that should not be neglected when calculating soil denudation rates and sediment budgets, i. e., soil loss due to crop harvesting (SLCH). Loose soil and soil adhering to the crop and rock fragments are harvested and exported from the field along with crops such as sugar beet (Beta vulgaris L.), potato (Solanum tuberosum L.) and chicory (Cichorium intybus L.). In this paper several assessments of SLCH found in the literature are listed, revealing that soil loss due to crop harvesting may range from a few Mg up to a few tens of Mg per hectare per harvest. As most literature discussing this soil loss does not originate from the field of earth sciences, and terms used to describe this phenomenon are not standardized, a terminology is proposed to describe soil losses due to crop harvesting compatible with terms used in the field of soil erosion. Furthermore, the parameters determining SLCH are reviewed based on a detailed literature study that focuses mainly on sugar beet. These parameters may be grouped into four factors, i.e.soil, crop, agronomic practices and harvest technique. Variations in soil moisture and soil texture cause the largest variations in SLCH, although other factors, such as harvest technique, also play an important role. Given the importance of SLCH in terms of on-site and off-site effects, more research is needed to quantify SLCH under different environmental conditions. [ABSTRACT FROM AUTHOR]