When is nitrogen removed when harvesting crops?

Nitrogen is removed from the soil during the harvesting of crops primarily when the plants are cut and removed from the field. As crops grow, they absorb nitrogen from the soil, and when the above-ground biomass is harvested, the nitrogen contained in the plant material is also taken away. This can lead to a depletion of nitrogen in the soil, necessitating appropriate soil management practices, such as crop rotation or the application of fertilizers, to replenish nitrogen levels for future planting.