Nitrogen deposition and how it influences root functioning in temperate forests

Quanying Du

February 19, 2009 @ 12:50 pm to 01:15 pm

10 Tyson

Atmospheric nitrogen (N) deposition is increasing as a result of N fertilization and fossil fuel use, and will have a large impact on forest ecosystem net primary productivity (NPP). The change of woody plant root life span under elevated N supply is crucial to understanding ecosystem-level C sequestration and nutrient cycling. Root lifespan is determined by standing crop and mortality. Root standing crop mostly decreases under elevated N, but mortality could change in different directions. Several factors exhibit stress on plant roots under chronic levels of high N, which in turn affect root mortality. Across 9 long-term N addition sites, the response of root lifespan to elevated N were different. By comparing site properties, we will be able to understand the mechanisms by studying root physiological responses in situ. I will also combine field research with controlled experiments in the greenhouse, to separate the direct effect of N addition, as well as the indirect effect of decreased soil solution pH and Ca/Al ratios.