What was done
Three varieties of winter wheat (Emma, Martina and Mezofold) were grown in controlled environment chambers at ambient (375 ppm) and twice-ambient atmospheric CO2 concentrations, as well as under poor and adequate soil nitrogen and phosphorus concentrations, in an attempt to determine the extent to which the aerial fertilization effect of atmospheric CO2 enrichment is impacted by soil nutrient deficiencies.

What was learned
Biomass production for the three wheat varieties was significantly influenced by nutrient supply, such that a smaller CO2-induced increase (up to 25%) was observed in plants growing under poor soil nutrient conditions, whereas when nitrogen and phosphorus were not limiting, the CO2-induced increase in biomass rose as high as 70% in the Emma cultivar.

The results of the study also indicated that the quality of the wheat was slightly reduced in two of the three varieties as a result of the doubled atmospheric CO2 concentration, but "only to a serious extent when nutrient supplies were poor."  The high-quality Emma variety, on the other hand, achieved good quality even with poor nutrient supply; and when adequate amounts of nitrogen and phosphorus were present, the quality of the other two wheat varieties improved as well.

What it means
With respect to quantity, atmospheric CO2 enrichment will likely increase the biomass production of all three varieties of wheat examined in this study.  As for the quality of the wheat produced, the Emma cultivar may be the best choice for growing in a high-CO2 world of the future.  For farmers choosing to remain with the Martina or Mezofold varieties, however, additions of soil nutrients should keep grain quality (protein concentration) at an acceptable level.  Thus, with a little tweaking of cultivars and soil nutrients, the world's future wheat farmers should be able to reap significant benefits from the CO2-enriched atmosphere that looms on the not-too-distant time horizon.