Ancient prairies as a reference for soil organic carbon content and microbial community structure

Authors: LORD, SAMUEL - University Of Missouri; Veum, Kristen; SULLIVAN, LAUREN - Michigan State University; ANDERSON, STEVE - University Of Missouri; Acosta-Martinez, Veronica; CLARK, KERRY - University Of Missouri

Submitted to: Applied Soil Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2024
Publication Date: 3/23/2024
Citation: Lord, S., Veum, K.S., Sullivan, L., Anderson, S., Acosta Martinez, V., Clark, K. 2024. Ancient prairies as a reference for soil organic carbon content and microbial community structure. Applied Soil Ecology. 198. Article 105355. https://doi.org/10.1016/j.apsoil.2024.105355.
DOI: https://doi.org/10.1016/j.apsoil.2024.105355

Interpretive Summary: Interest in monitoring and interpreting soil health and the soil microbial community has increased substantially over the past few decades. Landowners want to understand how their management decisions impact biological soil health, yet there is a lack of knowledge regarding the reference conditions for unmanaged, benchmark soils. Very few acres of remnant undisturbed prairie ecosystems remain in Missouri, and there is a lack of information on the soil microbial community in remnant prairies or in soils that have been returned to native vegetation following degradation from intensive land management. This study compared soil health in 35 sites across Missouri representing three prairie management conditions (i.e., remnant, restored, and reconstructed). The microbial community and the soil organic carbon content was highest in remnant prairies, followed by restored and reconstructed prairie systems. This study highlights the long-term impact of land disturbance and illustrates the importance of selecting remnant systems as the ecological reference standard for prairie lands. These results benefit landowners and conservation professionals seeking to establish reference sites for monitoring soil health and the effects of management practices.

Technical Abstract: Remnant undisturbed ecosystems contain a diverse array of plant and microbial life. The historic remnant prairies of Missouri display diversity above and below the soil surface and represent the few remaining acres of unconverted grassland habitat in the state. The soil microbiome is foundational to nutrient acquisition, resource partitioning, and ecosystem resilience; therefore, the intact plant-soil interactions of remnant prairies can serve as a reference for healthy microbial communities and ecosystem services lost due to land conversion. In this study, 35 sites across Missouri representing three prairie management conditions (i.e., remnant, restored, and reconstructed) were compared to assess differences in the microbial community structure and biomass using phospholipid fatty acid (PLFA) analysis. Soil organic carbon (SOC) content provided a measure of substrate available to support microbial community health. Total microbial biomass, the biomass of individual microbial groups (i.e., Gram positive, Gram negative, Actinobacteria, arbuscular mycorrhizal fungi, saprophytic fungi, and eukaryotes), selected biomarker ratios, and SOC, were significantly different across treatments and were highest in remnant prairies. This study demonstrated that the soil microbial community in reconstructed and restored prairie systems remained significantly diminished relative to remnant prairies, even after several decades. This study highlights the need to preserve remnant prairies, where soil is in its native state under native flora and abiotic conditions. These results also illustrate the importance of selecting remnant systems as the ecological reference standard for prairie lands.