WASHINGTON (AP) _ In the latest addition to the nation's largest conservation program, the government said today it will pay farmers nearly $40 an acre not to grow crops on 16.1 million acres of land.

Agriculture Secretary Dan Glickman said the total, an area about the size of West Virginia, includes 4.4 million acres that are particularly environmentally sensitive.

``We set out to enroll land that would yield the highest environmental benefits, keep productive cropland growing food and fiber and be fair to taxpayers in providing the most environmental bang for the buck,'' Glickman told reporters.

The land will be enrolled in the Conservation Reserve Program. Farmers will be paid an average of $39.40 per acre to idle land, about $10 less per acre than the last CRP signup.

The cost to taxpayers is more than $636.2 million. But Glickman said that is $1.6 billion less than the program would have cost over 10 years at the higher rate.

Farmers offered more than 26 million acres to qualify for the program, which pays them through 10-year contracts not to plant crops. The acres are usually covered with grass or trees.

Contracts on about 21.2 million acres of land will expire by Sept. 30, and the Department of Agriculture is accepting 11.7 million acres of that land into the new CRP.

The Agriculture Department evaluated each piece of land under new rules that placed greater emphasis on environmental benefits.

At the same time, Glickman said millions of acres of productive farmland will now be returned to its proper use.

``Land that is not environmentally sensitive has no place in the Conservation Reserve,'' Glickman said. ``The CRP is not a supply management program.''

The announcement brought quick praise from some in Congress, including Senate Agriculture Committee Chairman Dick Lugar.

``Today's announcement means that the CRP will be more environmentally targeted and environmental,'' said Lugar, R-Ind. ``These goals are what Congress had in mind when it renewed the CRP in the farm bill.''

But some said some 6 million acres that were offered should be accepted also.

``The administration has broken faith with American agriculture and damaged an important and effective environmental program,'' said Republican Sen. Pat Roberts of Kansas, where farmers failed to get almost 200,000 acres into the program.

Glickman said farmers who didn't make the cut this time would have another chance in the fall.

Congress has authorized a total enrollment in CRP of about 36 million acres.

Regionally, 31 percent of the new CRP land is in the northern Plains; 21 percent in the mountain states; 15 percent in the southern Plains and corn belt, and 8 percent in the Great Lakes states. This figures are roughly the same as the previous breakdown.