PPL01 Konza prairie long-term phosphorus plots experiment

Increased nutrient inputs is one of many global change factors predicted to affect the composition and ecosystem function of plant communities. In general, nitrogen deposition decreases diversity and increases productivity. The effects of phosphorus addition have received less attention, however, and the interactive effect of both nutrients is likely to exacerbate diversity loss over time. Here we addressed whether chronic nutrient additions changed community structure and ecosystem productivity of a native tallgrass prairie. This study took place in an ungrazed watershed that is burned every two years. Two N treatments, 0 and 10 g m-2, and four P treatments, 0, 2.5, 5 and 10 g m-2 were crossed in a fully factorial experimental design. The experiment was initiated in 2002 and starting in 2003 nutrients were added at the beginning of each growing season. Plant species composition was surveyed both in the spring and late summer each year, and aboveground biomass was harvested at the end of each summer to estimate aboveground net primary productivity (ANPP).