Campus as Carbon Sink

Abstract

Soils are a major carbon sink, and as atmospheric carbon emissions continue to increase around the world, attention is being turned to soils as a possible way to offset these emissions. For institutions like colleges and universities that manage significant acreage and are increasingly seeking avenues toward carbon neutrality, quantifying and enhancing the amount of carbon held in campus soil may be a valuable addition to existing sustainability efforts. This study investigates how land cover and soil compaction affect soil carbon sequestration on a college campus in the Southeastern U.S. Areas of different land covers in one campus neighborhood were mapped using GIS software to determine predominant landscaping conditions. Grassy lawns covered 67.4% of the study area, perennial beds covered 22.9%, and annual beds covered 2.1%, making up the vast majority of permeable surface area. Compaction measurements and soil samples were taken from randomly selected points within each of these three land cover types. Soil samples were analyzed using Loss-on-Ignition (LOI) techniques to determine the percentage of soil organic carbon (SOC) by mass. Findings showed that compaction is strongly correlated with land cover, prohibiting the distinction between the impact of land cover vs. compaction on SOC content. Perennial beds were moderately compacted and contain more SOC than grassy lawns (average 8.02% vs. 6.37%) which were highly compacted. Annual beds were minimally compacted and showed the highest average SOC values of 23.97%, likely due to large inputs of compost rather than long-term biological soil carbon sequestration. The results of this study suggest that conversion of grassy lawns into perennial plant beds would increase SOC sequestration potential on campus, thereby contributing to university carbon neutrality goals by sequestering atmospheric carbon in the ground.