9629770 Hendrix Since 1978, long-term research has been conducted on the effects of tillage regimes and the impacts of biotic manipulations on soil organic matter (SOM) dynamics and nutrient cycling processes in a subtropical agroecosystem. After 15 years of conventional tillage and no tillage management, dynamics of water-stable aggregates and aggregate-associated soil organic matter have been described and monitored at the Horseshoe Bend experimental area at the University of Georgia. The formation and stabilization of macroaggregates in no tillage soils represents an important mechanism for the protection and maintenance of SOM that may otherwise be lost under conventional tillage practices. This mechanism may explain the nearly 18% higher soil organic matter content of no tillage soils as compared to conventional tillage soils. These differences in SOM are translated to changes in soil biodiversity and ecosystem functioning. Funding of this LTREB proposal will maintain these long-term experiments, and allow several short-term, mechanistic field experiments to be conducted. The dynamics of soil organic matter and the response by the soil community to these dynamics take place over decades. LTREB funding will allow these investigators the appropriate time frame to monitor these dynamics.
