Sequestering Organic Carbon in Soils Through Land Use Change and Agricultural Practices: A Review

Abstract

Climate change vigorously threats human livelihoods, places and biodiversity. To lock atmospheric CO2 up through biological, chemical and physical processes is one of the pathways to mitigate climate change. Agricultural soils have a significant carbon sink capacity. Soil carbon sequestration (SCS) can be accelerated through appropriate changes in land use and agricultural practices. There have been various meta-analyses performed by combining data sets to interpret the influences of some methods on SCS rates or stocks. The objectives of this study were: (1) to update SCS capacity with different landbased techniques based on the latest publications, and (2) to discuss complexity to assess the impacts of the techniques on soil carbon accumulation. This review shows that afforestation and reforestation are slow processes but have great potential for improving SCS. Among agricultural practices, adding organic matter is an efficient way to sequester carbon in soils. Any practice that helps plant increase C fixation can increase soil carbon stock by increasing residues, dead root material and root exudates. Among the improved livestock grazing management practices, reseeding grasses seems to have the highest SCS rate. KEYWORDS agroecosystems, climate change, negative emissions technology, net zero 1 INTRODUCTIONExtreme weather events and global warming are inevitable because of anthropogenic emissions of warming gases (greenhouse gases, GHG) in the future [1] . Over recent decades, the atmospheric carbon dioxide concentration and the global air temperature (Fig. 1)have been rising linearly, and the records of the extreme temperature and precipitation intensity kept being rewritten. Negative CO2 emissions (i.e., CO2 removals) to lock CO2 up from the atmosphere through biological, chemical and physical processes are pathways to mitigate the global warming. Land management, soil management, bioenergy with carbon capture and storage, CO2 capture from ambient air, enhanced weathering and ocean fertilization are purported to be main potential approaches for CO2 removals [4][5][6] . Shepherd [7] categorized the CO2 removal techniques into three groups according to places where they are applied to (land or ocean) and predominant interventions and assessed the techniques in terms of their effectiveness, timeliness, safety, affordability and reversibility. The first group is to sequester more C into their natural sinks for a long period. The second is to apply enhanced weathering techniques in land and oceans. The third is to apply advanced technologies to capture and store CO2 directly elsewhere. The options also have been reviewed for their costs, potentials, side-effects, and innovation and scaling challenges for their implement [8][9][10] . Hepburn et al. [11] proposed 10 CO2 removal pathways: (1) chemicals from CO2, (2) fuels from CO2, (3) products from microalgae, (4) concrete building materials, (5) CO2-enhanced oil recovery, (6) bioenergy with carbon capture and storage, (7) enhanced weathering, (8) forestry techniques...

Can adaptations of crop and soil management prevent yield losses during water scarcity? – A modelling study

“…(2023), we assume that adaptations in soil management (e.g., organic amendments, cover cropping) lead to an accumulation of SOC of an additional 1% down to a depth of 60 cm. An increase in SOC to varying degrees due to different management has been documented in many publications (Diacono and Montemurro, 2010;Gross and Glaser, 2021;Lianhai, 2022). We select a high value of +1% to analyze the upper limit of the potential with this somewhat hypothetical scenario.…”