After more than a decade of effort, the biotechnology industry has yet to produce any commercial crops engineered to reduce nitrogen fertilizer pollution, while traditional breeding and other methods have improved the nitrogen use efficiency of wheat, rice, and corn by about 20 percent to 40 percent, according to a report released today by the Union of Concerned Scientists (UCS).

“Nitrogen pollution is among the world’s worst environmental problems,” said Doug Gurian-Sherman, a senior scientist in UCS’s Food and Environment program and author of the report. “A number of very promising solutions have begun addressing the problem, but so far genetic engineering has yet to make a contribution.”

Plants, including commodity farm crops, need large amounts of nitrogen to thrive and grow. Soils often do not contain enough nitrogen for plants to attain optimal productivity, but many farmers apply far more synthetic nitrogen fertilizer to their soils than what the plants can use. More than half of the nitrogen fertilizer applied on U.S. farms, for instance, is not absorbed by crops, and much of it becomes a pollutant.

Nitrogen pollution causes harm in multiple ways. Chemical fertilizers from farms, for example, are the largest contributor to the Gulf of Mexico’s “dead zone”-an area the size of Connecticut and Delaware combined where excess nutrients indirectly rob the region of oxygen, making it uninhabitable for commercially valuable fish and other marine life for much of the year. In addition, nitrogen in the form of nitrate can seep into drinking water and become a health risk, especially to pregnant women and children. Nitrogen entering the air as ammonia, meanwhile, contributes to smog, respiratory diseases and acid rain, which damages forests and other habitats.