9523944 Ellis This proposal requests support of a third and final year of a postdoctoral research fellowship in biosciences related to the environment. The first two years were funded under DEB 9303261. The project, entitled "Nitrogen Cycling and Ecological Sustainability in Agroecosystems" relates nutrient cycling to long term productivity of agroecosystems by comparing nutrient cycles found in contemporary and traditional villages of the region. The project aims to investigate the ecological basis for long-sustained productivity of agriculture in the lake Tai region of China, with a goal of developing quantitative tools for appraising ecological sustainability in agroecosystems. Work during the two years of the original award has yielded interesting results, indicating that natural nitrogen inputs were important to sustaining productivity in the traditional system, but contemporary inputs of chemical nitrogen appear far higher than needed, and may cause pollution. An additional year of support will allow the PI to complete the dataset for two annual cycles of agroecosystem management and to process the dataset and derive nitrogen cycling indices.
