New study settles long-standing debate: Does agricultural erosion create a reservoir or source of carbon?

news7g02/19/2023

3 4 minutes read

In new research published today in the European Geosciences journal Biogeosciences, two scientists tackle the soil organic carbon erosion paradox.

A peer-reviewed publication

European Union of Geosciences

Diagram showing the effects of erosion and water deposition on the stabilization and loss of soil OC — IMAGE: TRANSPORT IN RUN: EXPANDATION AND TRANSPORTATION CAN TRANSPORT OC from Synthetic Protected State to Availability, where it mineralizes faster. Landfill: Erosionized OC Convexity MOVES OCs into LOW MINERALIZATION CONCEPT AND CAN ALSO INCREASE PROTECTION THROUGH SYNTHESIS. SUSTAINABLE SOIL COMBINATION: IN ERROR POSITIONS FORM NEW OC FROM NEW VEGETABLES INTO Erosionized SUSTAINABLE SOIL MAY REPLACE SOME OF THE REMOVED SOIL. OC. RESPONSIBILITY OF RIGHT PRINCIPAL PRODUCTION (NPP): Erosion and deposition MAY AFFECT ON THE NUTRITION AND THE STATE OF SOIL DEPARTMENT (AND THE SOIL POTENTIAL) AS well as ENVIRONMENTAL FACTORS OC INPUT CONTROLS Vs OUTPUT. see more
CREDIT: VALVE OOST, K. AND SIX, J.: CONTROLLED REGENERATION OF ORGANIC ORGANIC CARBON Erosion by WATER, BIOGEOSCIENCES, 20, 635–646, HTTPS://DOI.ORG/10.5194/BG-20 -635-2023, 2023.

In the century, Researchers has sounded the alarm that soil erosion is the biggest threat to global food security. As governments around the world move to implement soil conservation measures, a new debate has begun: does agricultural soil erosion produce a net source or source of organic carbon (OC)? The question is an important question, because carbon tank absorb more carbon than they release, while carbon source 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 one learn published today in the journal European Geosciences Union biological science, the two researchers show that the apparent soil organic carbon erosion paradox, i.e., whether agricultural erosion leads to pools or sources of OCs, can be reconciled when we consider the context geographical and historical landscape. The research is the result of a collaboration between UCLouvainBelgium and ETH Zurich.

Organic carbon series
Early studies suggested that a significant portion of soil organic carbon deposited on agricultural land would be lost to the atmosphere. They conclude that agricultural erosion is a source of atmospheric CO2, leading to the concept of a win-win situation: soil conservation measures that reduce erosion lead to healthier soil AND a carbon sink. big.

However, many recent studies have challenged this assumption and proposed another pathway for organic carbon to be eroded. They propose the concept of a “geomorphic OC pump” that transfers organic carbon from the atmosphere to upland soils recovering from erosion to burial sites where organic carbon is protected from decomposition in a mineralization context. short. Along this geomorphological conveyor belt, organic carbon originally fixed by plants is continuously displaced along the earth’s surface, where it can be stored in a sedimentary environment. These studies argue that a combination of organic carbon capture and terrestrial deposition can capture large amounts of carbon in the atmosphere, and thus erosion may in fact represent a reservoir. organic carbon.

“We demonstrate how these two competing views can coexist and so this study provides an understanding of differences in opinion,” explains Kristof Van Oost from the Earth & Life Institute, UCLouvain.

First time seeing the whole scene
John six from the Department of Environmental Systems Science, the Swiss Federal Institute of Technology, and ETH Zurich say these latest findings are the first account of how all the different carbon dynamics processes caused by erosion interact with each other. interact and counterbalance each other in determining net carbon flows from the terrestrial environment to the atmosphere.

Six and Van Oost conducted a comprehensive literature review that included 74 studies. Six explain the reasons for conflicting assumptions from previous studies. “We found that the perceived paradox was primarily related to not considering the full carbon flux associated with erosion. This led us to think that it would be good to explain the complexity of the entire carbon chain.”

At the heart of this paradox – they recognize – is the fact that the processes that cause water erosion operate on spatial and temporal scales, defining the relationship between water erosion and loss of organic carbon versus stable processes. Together they conceptualize the impact of water-contributing (sub)-erosion processes over time and space using decay functions.

Paradox reconciliation time scale
Both researchers found that soil erosion only generates atmospheric CO2 when small spatial and temporal scales are considered, while both sink and source emerge when using approaches. near multi-scale.

Over a very short period of time (seconds to days), erosion events transfer some of the soil’s organic carbon from a protected state to a readily available state, where it mineralizes to a gaseous form more rapidly. . In contrast, studies that treat erosion as a site of atmospheric carbon sequestration often consider the longer time period at which the geomorphological OC conveyor belt is active.

The researchers emphasize the need for erosion control because of the many benefits it brings to the ecosystem but recommend large-scale approaches to accurately represent erosion impacts on the cycle. global carbon program.

Looking to the future, Van Oost concludes: “Our understanding of the impact of soil erosion on carbon storage is primarily derived from studies conducted in temperate regions. Now we need new research on erosion effects in marginal lands as well as in the tropics.”