U.S. government data on which genetically engineered crops are in use and where they are planted is too vague to provide useful information on their impact on the environment, according to a group of researchers.

Environmental scientists from seven U.S. universities said the widespread planting of genetically modified crops since 1996 "represents a grand experiment" that could resolve the debate over whether more safeguards are needed to protect the surrounding environment from the altered crops.

"Unfortunately, this experiment cannot be analyzed because we lack well-documented maps depicting the varying prevalence of crops with specific GE [genetically engineered] traits each year," they wrote in a policy paper in the Friday edition of the journal Science.

The researchers said the first problem is finding the crops: U.S. Department of Agriculture data documenting the use of genetically engineered crops is compiled and aggregated to the level of states and not counties — making the results too crude to be of any use in assessing the impact of those crops on the surrounding environment.

Information on how crops are modified is equally vague, they say.

The USDA's National Agricultural Statistical Service categorizes GE crops in four categories:

  • Insect resistant.
  • Herbicide resistant.
  • Resitant to both insects and herbicides.
  • All biotech varieties.

This classification hides substantial variation, the scientists write.

"For example, 12 different combinations of one to three insecticidal proteins that kill caterpillars or beetles, or both, are produced by different varieties of GE corn and cotton currently registered in the United States."

The scientists recommend data on the use of GE crops be on a country scale to provide meaningful information and better link the information with existing information on agricultural practices for insecticide and pesticide use.

"Providing scientists access to data on GE crop use at the country scale is a small and relatively inexpensive step with enormous scientific public benenfits," they wrote.