How do soil erosion and runoff remove nitrogen from soils?

Soil erosion and runoff are significant pathways through which nitrogen is lost from terrestrial environments.1

• Soil Erosion: This process involves the physical disruption and removal of soil particles from the upper layers (A horizons) of the soil profile by forces such as flowing water, wind, or ice. Because these layers contain essential plant nutrients, including nitrogen, their removal results in a direct loss of these vital elements from the ecosystem.2
• Runoff: Water acts as the primary medium for the transport of chemical elements. Runoff facilitates the movement of nitrogen from the soil surface into lakes, streams, and eventually the oceans. This transport mechanism effectively flushes nutrients out of the terrestrial environment, preventing them from being retained for plant uptake.31

These processes, particularly when accelerated by human land-use changes, disrupt the natural nitrogen cycle by removing nutrients that would otherwise be recycled through biological processes like ammonification and nitrification.31