That stubble in the fields helps farms hold onto precious topsoil

Carl Eppley's 11-acre experiment created a lot of local curiosity. He heard reports of people looking at his fields. The talk at the local grain elevator, Mr. Eppley recalls, ''was something else.'' Even he was surprised at his success.

But after that first harvest in 1979, this north central Indiana farmer began to reap the benefits of a different way of farming.

It is called conservation tillage - and has been touted for some time as one solution to the nation's severe soil erosion problem. US Agriculture Secretary John Block has said it ''may be our best single hope for bringing excessive soil erosion under control.''

Every year, 3 billion tons of soil erodes from all cultivated United States cropland, according to preliminary data released last month by the US Agriculture Department's National Resources Inventory division. Water erosion causes an average acre of cultivated land to lose 4.8 tons of soil per year. Another 3.3 tons is lost to wind, the survey shows.

But observers are buoyed by the increased use of conservation tillage among farmers.

''It can do great things, provided you don't exceed the limitations,'' says William C. Moldenhauer, research leader of the National Soil Erosion Laboratory in West Lafayette, Ind.

Some form of the practice was used on 31 percent of the nation's cropland last year, according to a new survey by the Conservation Tillage Information Center in Fort Wayne, Ind.

''We think it's on the upswing,'' says Jim Lake, the center's field office corrdinator. This year, he says, conservation tillage will be used on 35 percent of the nation's cropland. And in 10 to 15 years, a conservative estimate would put the figure at 50 percent, he says.

What makes conservation tillage farmers so different? They leave untouched a lot of the stalks and stubble from previous crops, contradicting the wisdom of conventional row-crop farmers, who would plow under those remains.

It is that debris that made people so curious about Eppley's fields those first years.

''It's awfully hard for a (conventional) farmer to see all that,'' he concedes. He recalls an older farmer telling him: ''I never felt so sorry for a man in all my life.''

Eppley says he became interested in conservation tillage after agronomists found severe soil compaction on his 500-acre farm - apparently from too much heavy machinery riding over his land.

Then, in the fall of 1978, the Wabash County Soil and Water Conservation District acquired ridge tilling equipment and the next year set up several demonstration plots on farmers' land. It was the first such district to do so in the nation. One of those demonstration plots was Eppley's 11-acre parcel of corn.

''When the corn came up, I was never so surprised in my life,'' he recalls. Next year, he tried the technique on soybeans as well. By 1981, he had his own ridge tiller and was completely sold on the system.

Ridge till is one form of conservation tillage. Eppley's fields are a series of ridges about 8 inches high. When he began planting his corn last week, his equipment merely skimmed about 11/2 inches of soil off the top of the ridges to plant the seeds. Instead of hiring two or three farmhands as he used to do, he now does all the work himself. And he needs less machinery than conventional farmers.

His yields, meanwhile, have improved - especially in corn. His five-year average for five fields was 155 bushels per acre of corn with the ridge till, he says. His average for conventional farming was only 137 bushels.

The advantages of ridge till are especially noticeable in years with abnormal moisture, he says. During wet seasons, the ridges hold the water and don't allow it to run off and erode soil. In dry years, the water that falls is absorbed by the debris of previous crops and not allowed to evaporate.

There are a few drawbacks, observers say. Land with steep slopes requires additional measures to fight erosion, Mr. Moldenhauer says.

There has also been concern that the systems require more herbicides to control weeds than conventional practices, Mr. Lake says.

But a new study by his center found that farmers in northeastern Indiana, southeastern Michigan, and northwestern Ohio used only 4 percent more herbicides than conventional practices.

Eppley adds that financing problems may keep some interested farmers from getting the necessary equipment for conservation tillage this year. But he says he sees increasing interest among farmers.

''It's going to come,'' he says, surveying the ridged field closest to his home. ''The time is way past for farmers to start realizing what they've been doing to the soil all these years.''