Over the last decade, researchers have sounded the alarm on soil erosion being the biggest threat to global food security.
Over the last decade, researchers have sounded the alarm on soil erosion being the biggest threat to global food security. As world governments moved to implement soil conservation practices, a new debate began: does agricultural soil erosion create a net organic carbon (OC) sink or source? The question is a crucial one, as carbon sinks absorb more carbon than they release, while carbon sources release more carbon than they absorb. Either way, the answer has implications for global land use, soil conservation practices and their link to climate change.
In a new study published today in the European Geosciences Union journal Biogeosciences, two researchers show that the apparent soil organic carbon erosion paradox, i.e., whether agricultural erosion results in an OC sink or source, can be reconciled when we consider the geographical and historical context. The study was the result of a collaboration between UCLouvain, Belgium and ETH Zurich.
Read more at: European Geoscience Union
Transport in runoff: detachment and transport can shift OC from a protected state in aggregates to an available state where it mineralizes more rapidly. Burial: the deposition of eroded OC moves OC into a low-mineralization context and can also enhance protection via aggregation. Subsoil mixing: at sites of erosion new OC formation from new vegetation inputs into exposed subsoil by erosion may replace some of the eroded. OC. Net primary production (NPP) feedback: erosion and deposition may affect the nutrient and soil depth status (and hence soil fertility) as well as the environmental factors that control OC input versus output. (Photo Credit: Van Oost, K. and Six, J.: Reconciling the paradox of soil organic carbon erosion by water, Biogeosciences, 20, 635–646, https://doi.org/10.5194/bg-20-635-2023, 2023.)