Boston — ARIE BLIEK, a corn farmer in Lyon County, Iowa, is pleased. The United States government will pay him to grow nothing but grass and trees on 106 acres of his cropland for a decade. In fact, the government would like to pay many others to render idle up to 45 million acres of farmland across the United States by 1990 to prevent soil erosion, hold down crop surpluses, and create wildlife habitats.
Until a year ago, Mr. Bliek was producing an average of 140 bushels of corn per acre on what he describes as fertile ground. But his land is a portion of 118 million acres across the nation that the United States Soil Conservation Service has identified as ``highly erodible.''
Officials of the United States Department of Agriculture (USDA) hope to place most of this acreage under elaborate conservation plans mandated by Congress.
After years of warnings by soil experts and conservationists about the dire consequences of soil erosion - including its off-site repercussions - the government is in the midst of an ambitious and expensive program to conserve the nation's farmland.
Conservationists say that when Congress passed the Food Security Act of 1985, it significantly altered the course of conservation events in the United States. They hail the bill as the most important soil conservation legislation since the ``dust bowl'' of the 1930s.
The act - better known as the 1985 farm bill - directly linked a farmer's stewardship of his land with eligibility to receive a wide range of federal farm benefits.
Kenneth A. Cook, a senior associate with the Conservation Foundation, describes the bill as ``one of the most sweeping laws concerning the environment and conservation in the last 50 years.''
It has taken government agencies almost two years to develop administrative rules and guidelines to carry out the 1985 act, and many farmers are scrambling to meet deadlines.
The USDA calculates that at least 800,000 individual conservation plans will have to be developed before the Jan. 1, 1990, deadline. The law specifies that the plans have to be in place by 1995 to enable farmers to retain eligibility for government supports.
Arie Bliek enrolled in the Conservation Reserve Program, under which farmers volunteer to halt production on highly erodible cropland. If a farmer's bids are accepted, the government makes annual rental payments and provides assistance amounting to half the cost of planting grass, trees, and shrubs to guard against erosion and enable soil to renew itself.
By the end of 1987, 23 million acres of cropland across the nation had been signed into the reserve program. ``On that acreage, we estimate that we will save 467 million tons of topsoil a year,'' says David Moffitt, public affairs specialist with the Soil Conservation Service.
Through periodic ``sign-ups'' the USDA accepts farmers' bids to participate in the program. In May the department will announce how much more land has been accepted as a result of a sign-up that ended in February. A seventh sign-up will take place July 18 through Aug. 5.
Mr. Cook estimates that the Conservation Reserve Program could cost US taxpayers $13 billion in the next decade - more than $1 billion a year in rental payments and cost-sharing to farmers. Conservation officials estimate that 90 percent of the farmers in most Midwestern states participate in some federal benefit program.
USDA officials say many farmers tilling erodible soil would fall under the ``Highly Erodible Land and Wetland Conservation'' provisions of the farm bill - commonly referred to as the ``conservation compliance,'' ``sodbuster,'' and ``swampbuster'' rules.
The sodbuster rule discourages planting crops on grassland and woodland. The swampbuster provision discourages converting wetlands to croplands by draining them.
Although conservationists have lauded the far-reaching goals of the farm bill in its effort to stem topsoil loss, they warn against expecting immediately visible benefits.
``We are looking 10 years down the road to realize any significant benefits of the CRP program,'' says Rex Wright, deputy director of the conservation and environmental protection division of the Agricultural Stabilization and Conservation Service.
But questions remain: What happens to the land after the contracts expire in 10 years? Does it go back to agricultural use?
Bill Armbrust, a farmer in eastern Nebraska, says many farmers in his area believe grain markets will improve considerably in a few years. If that happens, he says, farmers will not need government programs and some would be less inclined to practice conservation.
Max Schnepf of the Soil and Water Conservation Society of America warns that if conservation is once again put on the back burner, ``At some point,'' even if not in the lifetimes of today's farmers, ``the land will lose all its productivity.''
``If we continue mining our soil,'' Mr. Armbrust says, ``we are headed backward.''
Meanwhile, in the soft loess hills of Lyon County, Iowa, on what was once a 106-acre cornfield, Arie Bliek now spots deer roaming amid the grass and legumes.