Soil Organic Carbon Quantification by Habitat Type in South Central Texas

An increase in atmospheric CO2 has become a growing concern due to enhanced greenhouse effects. Climate change factors, such as increased temperature and greater variability precipitation patterns, have the potential to decrease soil organic carbon (SOC) pools. Soil plays a key role as a soil carbon sink and can influence soil characteristics and soil quality. Through soil carbon sequestration, atmospheric carbon is taken up by plants and moved into the soil profile through root systems or plant litter. This study provides insight and baseline information on the sequestering abilities of soils in three different habitat types (maintained, grassland, shrub forest) and the effect of season in South Central Texas. Soil samples were analyzed for soil texture and organic carbon during the winter (2019) and summer (2020) seasons. Differences among SOC detection were compared with the Shimadzu TOS-SSM and Loss on Ignition methods. There were significant differences in SOC among habitat types. Shrub forest contained 106% more SOC for grassland habitats and 77% more SOC than maintained habitats. A seasonal difference was not found. The comparison of analytical methods revealed significant differences in SOC detection, where a coefficient of variation showed the Shimadzu TOC-SSM was nearly double the value obtained by the LOI method. This suggests that the LOI had lower variation in results than the Shimadzu TOC-SSM, though more comparisons studies are needed to establish an efficient protocol. Shrub forests should be preserved into perpetuity to provide carbon sinks, and grassland and maintained habitats should be studied to increase SOC pools.