Nitrate leaching in urban ecosystems
Peter Groffman, Institute of Ecosystem Studies
The Baltimore Ecosystem Study (BES) has maintains a network of long-term permanent biogeochemical study plots. These plots provide long-term data on vegetation, soil and hydrologic processes in the key ecosystem types within the urban ecosystem. Plots are instrumented with lysimeters (drainage and tension) to sample soil solution chemistry, time domain reflectometry probes to measure soil moisture and trace gas flux chambers to measure the flux of carbon dioxide, nitrous oxide and methane from soil to the atmosphere. Measurements of in situ nitrogen mineralization, nitrification and denitrification are made at approximately monthly intervals. Detailed vegetation characterization (all layers) was done in summer 1998. The current network of study plots includes eight forest plots, chosen to represent the range of forest conditions in the area, and 4 grass plots. The network is being expanded to include more grass plots, urban yards and wetlands. Here we present data on nitrate leaching from the forest and grass plots.