Purdue Climate Change Research Center

Impacts of Vegetation Change on Stabilization and Microbial Accessibility of Soil Organic Matter: A Microbiological, Isotopic and Molecular Study

Funded by the National Science Foundation

Aggregation and Disaggregation exampleSoil organic matter (SOM) and associated litter represents the largest actively cycling pool of organic carbon (OC) and nitrogen (ON). Because soil acts as both a sink and a source for carbon, a detailed, mechanistic understanding of the controls on the conversion of litter OM to SOM, and its stability in soil is critical to accurately account for the changing balance between the atmospheric, terrestrial plant, and soil carbon reservoirs. In mid continent and northern North American forests there is an increasing awareness of the effect that detritivore macroinvertebrates, specifically earthworms (EW), have on litter decay dynamics and the associated nature of stabilized SOM. Well-documented effects of earthworm introduction into forests with few or no native EW include the depletion of organic horizons, forest floor litter, loss of soluble nutrients, and mixing of mineral and organic horizons. Surprisingly, however, earthworm activity, with its feedbacks to enzymatic activity, microbial community structure, and plant biopolymer alteration, is generally not one of the considerations applied to influences on SOM stabilization. This proposal seeks to document and quantify how these protective mechanisms interact in natural and experimental systems impacted by different degrees of EW activity. Our focus is primarily on identifying how differences in invasive EW activity and feeding habit interact with differences in litter chemical composition, mineralogy, and microbial enzyme activity among locations in the same temperate forest to alter the relative importance of physical, chemical, and biochemical protection mechanisms controlling SOM stabilization.


  • Timothy Filley, EAS
  • Diane Stott, National Soil Erosion Lab
  • Thomas Boutton, Texas A&M

Contact Information

Purdue University
203 S. Martin Jischke Drive
MANN 105
West Lafayette, IN 47907