The DIRT Experiment (Detritus Input and Removal Treatments) is a long-term study of controls on soil organic matter formation. Our goal is to assess how rates and sources of plant litter inputs control the accumulation and dynamics of organic matter and nutrients in forest soils over decadal time scales. Results from 11 years of field and laboratory studies demonstrate the relative importance of above- and belowground sources on soil organic matter (SOM) dynamics and show emerging long-term non-linear changes in soil carbon release and storage. ref: Harvard Forest website - http://harvardforest.fas.harvard.edu/data/p00/hf007/hf007.html