WASHINGTON — The U.S. Department of Agriculture late Friday gave farmers partial approval to plant bioengineered sugar beet seeds this year as a temporary interim measure until the agency completes a more thorough study expected to take about a year.

Growers will have to enter into a compliance agreement outlining mandatory requirements for how the crop may be grown, although restrictions were not yet detailed. The decision was made so farmers may make planting decisions this spring, according to the U.S.D.A.

The U.S.D.A.’s Animal and Plant Health Inspection Service, after conducting an environmental assessment, determined the bioengineered sugar beet seeds may be partially deregulated without posing a plant pest risk or having a significant effect on the environment.

Planting of bioengineered sugar beets currently is under a ban from a U.S. district court in California as the result of a lawsuit brought by organic growers and environmental groups. That case still is pending, in part awaiting the U.S.D.A. full environmental impact study, which isn’t expected until May 2012.

About 95% of U.S. sugar beet acreage was planted to Monsanto’s Roundup Ready sugar beet seeds in 2010.