The Midwest is flyover country, as they say. From 35,000 feet, the landscape is a lovely patchwork of geometric field shapes, parallelograms stitched neatly together. But close up, Midwest farmland is not such a pretty picture.
Farm animals are often packed into factory-size buildings. Next to these are open-air waste pits as large as small lakes. They hold millions of gallons of untreated, liquefied manure.
Just as foul, and completely hidden, are the underground pipes crisscrossing and draining the watersheds of the Midwest. Pieced together, they’re the largest sewer in the country.
These pipes are called drain tiles. From Ohio to Iowa, in a network estimated at more than 3 million miles, they underlie most farm fields to drain away rainwater. But they also carry farmland pollutants directly to creeks and rivers. They are agriculture’s dirty secret.
Across southern Michigan, where I live, 19th century settlers found forests and swamps. You can’t farm in either. So the pioneers cut the trees. And to make fields from swamps, they dug trenches and buried drain tiles, creating underground tributaries.
The word “tiles” comes from the early use of foot-long sections of clay pipe, made in the brickworks of many small towns. Now farmers use perforated plastic pipe, laser-sighted downhill.
In the Midwest, tiles drain up to 60 percent of agricultural land. When big confinement dairies were built recently in my watershed, their builders re-tiled the land where they would dump liquid manure.
In cities, sewers once combined storm water and human waste, creating a serious problem of contaminated overflows. Now storm water normally drains through one set of pipes, and human waste flows through another to treatment plants.
But agriculture has largely ignored its own combined — and continuous — contribution of sewage to our waterways.
No wonder — the problem is huge. The tiles cover vast areas. Some tile systems are new, some 100 years old, with fixes from every generation along the way. In many soils, wormholes — more than you might think — and large cracks are direct pathways, like straws, to subsurface tiles. Liquids can pour through in minutes.
Across the country, agriculture now contributes more pollution to lakes and streams than any other industry. The widely reported dead zone in the Gulf of Mexico is one result of the runoff of excess nutrients from manure and fertilizers. And now another is forming where streams in my part of Michigan flow — in Lake Erie, which had finally recovered from the industrial pollution of the mid-20th century.
In large livestock confinement operations, animals are never on pasture, where they would be spread out feeding on grass and where living soil could use and absorb their drier manure. Instead, the waste is liquefied, pumped to a lagoon, then sprayed untreated on fields, where it runs quickly into the tile drains. The liquefying is done with groundwater — it’s polluted coming and going.
It is time we fixed the plumbing.
Livestock production, like other industries, should be required to treat its waste. Technologies exist for liquid-solid separation with accompanying wastewater treatment. There are dry systems for manure handling that are hybrids of rotational grazing and winter composting. Agriculture doesn’t have to reinvent the wheel. Better yet, livestock operations can downsize to farm size. Get lean and green.
From the air, Midwest farmland still looks like a comforting quilt. What you don’t see is what’s unsettling. You don’t see the animals inside the confinement buildings. You don’t see the waste pits holding millions of gallons of liquid manure — they look like innocent lakes from high up. And you don’t see the stream of pollution flowing through subsurface drainage tiles — agriculture’s unregulated sewers.
JANET KAUFFMAN has restored wetlands on her farm in Michigan. She coordinates the Water Monitoring Project for Environmentally Concerned Citizens of South Central Michigan. Kauffman wrote this piece for the Prairie Writers Circle at the Land Institute, Salina, Kan.