Innovation in the Heartland: Manure spreader

When I was about ten years old, I had a vacation from school that my sisters didn’t have. So I was home with Mom and Dad without competition for attention. I wanted to help Dad outside instead of practicing my ironing, which I hated. It was spring, and Dad’s job for the day was cleaning out the hog pens and loading the manure into the manure spreader. I was very proud to help with this stinky job until I slipped and fell in it. Dad lost his patience at that point and increased my vocabulary. “You’ve got shit all over you. Go in the house and get cleaned up.” Oh, I thought, as I walked up the driveway. That’s what shit is! I’d heard the term at school but hadn’t until that moment known what it meant.

It is, of course, a fact of life at every level. We have indoor plumbing but also a septic tank to process what we flush. The dogs leave their calling cards all over the yard. Bryan picks it up and removes it to the woods. It’s not good for fertilizer, I understand, because the carnivore’s diet leads to high acidity, or too much nitrogen and phosphorous, or bacteria and parasites, or some other reason? One of the items in those same woods is the remnants of a manure spreader.

Archeological evidence puts the use of manure as a fertilizer at some 8,000 years ago. And for most of that 8,000 years, farmers in long-settled places like Europe gathered it by hand and spread it by hand across their fields. It was the only readily available fertilizer they had, and its value in maintaining land that was farmed for literally thousands of years was recognized even by the Roman poet Virgil.

As a fertilizer, manure contains high levels of the things that plants need to flourish–nitrogen, phosphorous, potassium, magnesium, calcium and sulfur among others. It also enriches the soil by adding carbon and organic materials. 

At first, farmers in the New World didn’t bother with fertilizing. They used a field of tobacco or corn until it stopped producing, and then, believing that the supply of fertile land was endless, they just left that field fallow and cleared another one.

By the mid-1800s, the reality began to sink in that land was in fact a finite resource that needed to be conserved. Harking back to their European roots, farmers in Iowa and the Midwest began spreading manure on their fields. This was an onerous, smelly and backbreaking job. First, they had to gather it up. Then they had to pitch it as evenly as possible over the fields. With hogs, cattle and chickens on the farmstead, there was plenty of it to spread around.

Between 1850 and 1875 several efforts were made to patent ideas for mechanized manure spreaders, but none took hold. Then, in 1875, John Kemp devised a model that would spread the stuff out the back of a wagon in a narrow line. His mechanism included a wagon with a chain on either side that moved as the wheels turned. Between the chains were a series of bars that scraped along the wagon bed, pushing the manure toward the back. The chains and bar mechanism operated in a continuous loop driven by being geared to the wagon’s wheels. So when a horse pulled the wagon, it started emptying itself. The farmer still had to go into the field and spread out the lines of manure with a rake.

The next major invention came in 1899. Joseph Oppenheim patented an improvement in the form of a steel axle at the back of the wagon that held a series of paddles. The paddles were angled in such a way that they pulverized the manure and spread it out in a fan shape that was wider than the wagon itself. That covered more of the field and eliminated the need to spread it out by hand. Oppenheim founded the New Idea Spreader Company and began manufacturing his new designs. Major ag equipment manufacturers such as International Harvester, were making this improved version by 1905. The one in the woods on Owl Acres is too deteriorated to be readily identified by brand. Some time in the 1940s or 1950s, this ground-driven version was probably abandoned for a better model that worked off the power takeoff on a tractor. 

Every spring we have a few days on Owl Acres where the smell reminds us that using manure as fertilizer is a continuing practice in  Iowa. With the large numbers of livestock production facilities in Iowa, though, there’s just way too much of it to use it all up on the nearby fields.  Major concerns about pollution of our rivers and streams pit environmentalists against the livestock producers. This ongoing tug-o-war has forced new standards in waste disposal, but the problem is not completely solved. When I was a kid, whenever we passed a feed lot or hog facility, my dad would say “That’s the smell of money.” He was a hog and cattle farmer after all.

Photo by Author. Alt text: A discarded, ground-driven manure spreader emerges from the tangle of forest floor vegetation every fall. The implement is a horse- or tractor-drawn wagon with a moving floor and whirling beaters attached at the rear. When operating, chains and bars scrape along the bottom of the wagon box and deliver material to the spinning spreaders, which pulverize the manure and fling it wide and far onto the ground behind. Power comes from the team (or tractor) through gears driven by the rear wheels. Angled lugs stud the wheel rims. The lugs grip the soil and transfer power to run the machinery.