Productivity and Water Use of Wheat Under Free-Air CO sub(2) Enrichment

Research has shown that elevated atmospheric carbon dioxide concentrations can accelerate plant growth and could potentially increase agricultural productivity, due to the effects on photosynthesis. The free-air CO sub(2) enrichment (FACE) technique for exposing plants to elevated CO sub(2) has been developed, and a FACE experiment was conducted in Arizona using Triticum aestivum. The effects of water supply were also examined using Wet and Dry plots. Results from the experiment are presented in terms of plant development and senescence, canopy photosynthesis, leaf area, biomass accumulation, grain yield, and the daily and seasonal energy budgets. The data indicated net canopy photosynthesis was enhanced 19 and 44%, respectively, in the Wet and Dry plots. As the temperatures increased in the spring, the FACE plants grew abut 20% more than the control plants at ambient CO sub(2), and the FACE plants matured and senesced about one week earlier than the controls.