Submitted to: Seed and Soil Dynamics in Shrubland Ecosystems Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/5/2003
Publication Date: 6/9/2004
Citation: Norton, J.B., T.A. Monaco, J.M. Norton, D.A. Johnson, and T.A. Jones. 2004. Soil morphology and organic matter dynamics under cheatgrass and sagebrush-steppe plant communities. Journal of Arid Environments 57: 445-466. Interpretive Summary: Soils beneath cheatgrass and native plant communities were compared for structural, morphological, and chemical properties. Cheatgrass inputs less decomposable organic matter to soils. Cheatgrass also enhances organic matter decomposition which could result in long-term loss of total organic material in soils, making it tough to restore plant communities.
Technical Abstract: Widespread cheatgrass (Bromus tectorum L) invasion represents a major shift in species dominance that may alter ecosystem processes across much of the western U.S. To investigate differences following such conversion, soil morphology and organic matter under cheatgrass-dominated and native shrub-steppe vegetation were compared by standard soil analysis procedures at seven paired sites in Idaho and Utah. Results suggest that, following conversion to cheatgrass dominance, increased porosity and labile organic inputs enhance microbial decomposition in near-surface horizons beneath cheatgrass compared to adjacent soils under native vegetation. Together with smaller inputs of less decomposable soil organic matter (SOM) from cheatgrass than native vegetation, enhanced decomposition could result in depletion of long-term SOM, leading to impoverished sites difficult to restore to native perennial vegetation.