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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.

Biochar addition to soils has been proposed as a means to increase soil fertility and carbon sequestration. However, its effect on soil nitrogen (N) cycling and N availability is poorly understood. To gain better insight into the temporal variability of the impact of biochar on gross soil N dynamics, two 15 N tracing experiments, in combination with numerical data analysis, were conducted with soil from a biochar field trial, 1 day and 1 year after application of a woody biochar type. The results showed accelerated soil N cycling immediately following biochar addition, with increased gross N mineralization (+34%), nitrification (+13%) and ammonium (NH 4 + ) and nitrate (NO 3 À ) immobilization rates (+4500% and +511%, respectively). One year after biochar application, the biochar acted as an inert substance with respect to N cycling. In the short term, biochar's labile C fraction and a pH increase can explain stimulated microbial activity, while in the longer term, when the labile C fraction has been mineralized and the pH effect has faded, the accelerating effect of biochar on N cycling ceases. In conclusion, biochar accelerates soil N transformations in the short-term through stimulating soil microbial activity, thereby increasing N bio-availability. This effect is, however, temporary.

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