Irrigation experiments are linked with nitrogen fertilization experiments. 36 plots of 32 species receive nitrogen fertilization of 0, 7, or 14 grams per square meter. Plots are open and receive normal rainfall, but selected plots also receive irrigation of approximately an inch of water per week. These treatments are implemented to determine conditions for highest productivity levels in biofuel production.
Water removal experiments take place in the BioCON rings. Ongoing BioCON experiments explore the interaction of key plant resources such as CO2 and N with biodiversity levels. Recently implemented experiments study the effects of lower levels of rainfall on plots with 9 species. Rainout shelters are erected prior to ~50% of rainfall events in the months of May, June, and July. Biomass increases similarly with elevated CO2 across lower rainfall and ambient rainfall plots, which does not suggest a link between elevated CO2 levels, dry conditions, and increased plant biomass.
