30 years of free‐air carbon dioxide enrichment (FACE): What have we learned about future crop productivity and its potential for adaptation?

Abstract Free‐air CO 2 enrichment (FACE) allows open‐air elevation of [CO 2 ] without altering the microclimate. Its scale uniquely supports simultaneous study from physiology and yield to soil processes and disease. In 2005 we summarized results of then 28 published observations by meta‐analysis. Subsequent studies have combined FACE with temperature, drought, ozone, and nitrogen treatments. Here, we summarize the results of now almost 250 observations, spanning 14 sites and five continents. Across 186 independent studies of 18 C 3 crops, elevation of [CO 2 ] by ca. 200 ppm caused a ca. 18% increase in yield under non‐stress conditions. Legumes and root crops showed a greater increase and cereals less.…

• AR
  Agricultural Research Service