Dr. Knute Nadelhoffer (University of Michigan Department of Ecology and Evolutionary Biology Professor Emeritus) will present this year's Bennett Endowed Lecture in Plant & Fungal Ecology: Biological Controls on Forest Soil Organic Matter Accumulation:
Lessons from the DIRT Collaboration.

Globally, soils store more than twice as much carbon in organic forms as exists in the atmosphere as carbon dioxide (CO2). Because plant-soil systems, such as northern forests, exchange carbon with the atmosphere, small percentage changes in carbon contents of extensive ecosystems such as temperate forests can lead to significant changes in atmospheric CO2¬¬, a powerful heat-trapping gas that affects global temperatures. In addition to serving as a global carbon reservoir, soil organic matter (SOM) is a critical ecosystem component that affects soil physical, chemical, and biological properties. SOM serves to increase soil water retention, to store, recycle, and release nutrients for forest tree growth, and to protect stream and groundwater quality. Importantly, SOM enhances environmental conditions leading to high levels of biodiversity consisting of complex microbial and faunal communities that serve to maintain ecosystem and human health.

This talk will present results from a network of long-term experiments, referred to as “DIRT” (Detrital Input and Removal Treatments, including a 15-year experiment at the UM Biological Station), which is focused on understanding how forest leaf and root litter function to control SOM accumulations in forest soils.