At the USDA Grassland, Soil and Water Research Laboratory, I have established a field site for monitoring the carbon and water fluxes and productivity of the CAM species Opuntia ficus indica under different water stress conditions simulated with an irrigation system of my design. The field site accommodates 3 different agricultural watering practices: rainfed conditions, stress-avoidance irrigation, and deficit irrigation. This new field site will provides data for understanding the long term productivity and economic viability of Opuntia ficus indica as a biofuel feestock.