Workers at McPherson County Feeders, a beef feedlot in Marquette, Kan., periodically have to drain waste retention ponds and scoop out manure with heavy equipment. (Jeremy Bernfeld/Harvest Public Media)
Imagine if you could use the carbon-dioxide that comes out of your car’s tailpipe to power a machine that produces the gas you use to run your car.
For centuries, farmers have used manure produced by livestock to fertilize their fields. Today, with many livestock producers packing thousands or hundreds of thousands of animals on to a few hundred acres, the process is basically the same, if more challenging.
Feedlots are required to collect and control all of the waste their cattle produce to ensure environmental safety. But according to producers and regulators alike, much of that waste can be used properly and effectively to fertilize fields. In many cases, cattle waste can be used to fertilize fields that then grow feedstock consumed by those same cattle.
Angie Rieck-Hinz, an extension specialist at Iowa State who works with the Iowa Manure Management Action Group, says when it’s done right, controlling the nutrients in manure can be a form of recycling.
“We’re looking at capturing and re-distributing those nutrients so that they’re used as a resource – primarily a nutrient resource or a fertilizer source for crop production,” Rieck-Hinz said.
Manure is full of chemical elements like phosphorous, ammonia and nitrogen, which can contaminate water if uncontrolled in excessive amounts. But those same kinds of chemicals are used to create synthetic fertilizers.
For feedlot owners dealing with the waste of many thousands of cattle, the key is to farm enough cropland to be able to spread the vast amount of manure they’re controlling in such a way that it will be both diffuse enough to be safe and beneficial enough to be economical.
“It has all the nutrients we need for crop production, but when they move off-site or when they’re mismanaged environmental concerns come down to, normally, water quality issues,” Rieck-Hinz said. “(The nutrients) can potentially cause water quality problems and (then) we’re not using our resource in the best way to maximize the economic potential of those nutrients.”
Of course, as production continues to shift more and more to Concentrated Animal Feeding Operations – huge feedlots on a relatively small area – environmentalists worry that individual feedlot operators dealing with massive amounts of waste will struggle to dispose of it properly.
“We’re already talking about concentrated waste and when the wastes become even more concentrated – more and more CAFOs on a small amount of a land or a relatively small location – it really exacerbates the problem,” Burkholder said. “The land and water and air just can’t absorb the waste very well without major pollution problems.”
Federal and state regulators do their best to ensure that animal waste doesn’t contaminate the water supply and many feedlot operators install systems that combine waste control with field fertilization. After all, with the price of fertilizer booming, they have an economic incentive to use their animal waste effectively.
As part of an approved plan to manage waste, feedlots install networks of drainage canals and lagoons. Many operators pipe the waste directly from retention structures to center-pivot irrigation systems on neighboring fields. They also scrape manure from animal pens and can distribute it to crops manually.
From cow to lagoon to field to cow…or is it from field to cow to lagoon to field?