Managing grasslands to optimise soil carbon sequestration

Authors: CHABBI, ABAD - Institut National De La Recherche Agronomique (INRA); RUMPEL, CORNELIA - National Council For Scientific Research-Cnrs; KLUMPP, KATJA - Inrae; Franzluebbers, Alan

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/1/2022
Publication Date: 11/8/2022
Citation: Chabbi, A., Rumpel, C., Klumpp, K., Franzluebbers, A.J. 2022. Managing grasslands to optimise soil carbon sequestration. In: Rumpel, C., editor. Understanding and fostering soil carbon sequestration. United Kingdom: Burleigh Dodds Science Publishing Limited. Chapter 18.

Interpretive Summary: Management of forages and pasture-based livestock production systems can be a sink for carbon dioxide from the atmosphere via soil organic matter storage, but these systems can also be a source of greenhouse gas emissions via enteric methane and soil nitrous oxide following fertilization. A scientist from USDA Agricultural Research Service in Raleigh North Carolina collaborated with scientists from the National Institute of Agricultural Research in France on a summary of recent research and literature review in a book chapter describing the impacts of grassland management on soil carbon storage and greenhouse gas emissions. Ruminant livestock naturally emit enteric methane, but dietary quality and herd management can alter the emission index. Nitrous oxide is a powerful greenhouse gas that often increases following nitrogen fertilization, so accurate fertilizer recommendations can mute this emission source. These emissions can be offset by storage of carbon in soil organic matter during pasture development since grass roots and residues are important contributors to organic matter stabilization. This review will be useful for scientific investigators, policy makers, and non-governmental organizations interested in land management systems for mitigating and adapting to climate change.

Technical Abstract: Managed grasslands, such as prairies and pastures, are favorable systems for increasing soil organic C storage. With ruminant livestock as the primary consumer of these forages, enteric methane emission is the primary driver of greenhouse gas emissions from either hay-harvested prairies or grazed pastures. Nitrous oxide is a potent greenhouse gas and its emission is linked to the periodic concentration of available N in soil. Accumulation of soil organic C with grassland development can be a strong sink for atmospheric CO2, thus potentially negating other greenhouse gas emissions. Grassland systems can be managed to reduce net greenhouse gas emissions by understanding the benefits and trade-offs of different management approaches that ultimately affect plant and animal productivity, environmental quality, biodiversity, and socio-economic outcomes. Achieving a positive balance between soil organic C sequestration and emission of methane and nitrous oxide from livestock, management strategies may need to acknowledge trade-offs in ecosystem service outcomes, which will be dependent on soil and climatic conditions of a particular region. Innovative systems such as integrated crop-livestock systems or silvopastures are more ecologically diverse. Co-benefits of these more complex agroecosystems include income stability for producers and increased resilience of agricultural systems against climate change.