Field tests by University of California-Davis scientists have shown that high levels of carbon dioxide inhibit plants’ ability to assimilate nitrates into proteins. This research shows that high carbon dioxide levels could negatively impact the nutritional quality of food crops such as wheat, barley, rice and potatoes, the scientists report.

Although many within the environmental community are linking the findings to a warning that climate change could cause problems with crop nutrition, this research doesn’t appear to be completely climate change news. A current example of nutrition deficiency by plants grown in high carbon dioxide environments might be China where air pollution is a major problem.

As those in agriculture know, assimilation of nitrogen plays a key role in plants’ growth and productivity. What might not be recognized as much, according to the report, is that plants use nitrogen to produce the proteins that are vital for human nutrition.

What the researchers reported, and related to the potential increase in carbon dioxide in the air in future years, was not completely new because it originated from 1996 and 1997 field demonstrations in Arizona where carbon-dioxide-enriched air was released in wheat field plots. What was new was technology that allowed the research scientists to analyze dried leaf material from the fields that had been stored.

“The researchers found that three different measures of nitrate assimilation confirmed that the elevated level of atmospheric carbon dioxide had inhibited nitrate assimilation into protein in the field-grown wheat,” wrote Will Parker for in reporting on the research.

This decline in nitrate assimilation probably can be compensated for with additional nitrogen fertilizer although environmental activists condemn the thought of added nitrogen being applied to fields and the extra nitrogen will cost farmers.