Commentary: Horse-drawn manure injector designed to entice Plain Sects

By Ad Crable
Posted 12/4/21

The newest tool to get more farmers in the Chesapeake Bay watershed to inject their manure into, rather than onto, their fields was trotted out this summer with a team of eight draft horses.

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Commentary: Horse-drawn manure injector designed to entice Plain Sects


The newest tool to get more farmers in the Chesapeake Bay watershed to inject their manure into, rather than onto, their fields was trotted out this summer with a team of eight draft horses.

Touted as the world’s first animal-powered manure injector, the equipment debuted on a farm in Lancaster County, Pennsylvania, where dozens of Plain Sect farmers gave it the once-over.

The horse-drawn (or mule-drawn) manure injector was built with the hope of persuading Amish and Old Order Mennonite farmers in the county to fertilize their fields by depositing manure deep into the soil, instead of spreading it on top of the ground where it can wash off the land and pollute streams. Nutrient pollution from manure is a major source of water-quality problems in the Chesapeake Bay and its rivers.

The Plain Sect target is strategic. Lancaster County is, by far, Pennsylvania’s largest source of nutrient loadings into the Bay. And Plain Sect farmers work about half the county’s farm acreage. For generations, they have used the manure that builds up in their small dairy operations as fertilizer, applying it to fields with animal-drawn spreaders.

By injecting manure several inches into the soil and covering it, the vital nutrients of nitrogen and phosphorus stay there and don’t wash off in heavy rains. Also, loss of nitrogen into the atmosphere in the form of ammonia gas has been a problem with the surface spreading of manure. The farmer loses nutrients, and the gas contributes to air pollution.

Lancaster County’s countywide action plan, part of the state’s Bay cleanup plan, calls for the use of manure injection on 10,000 acres in the county by 2025.

Tractor-pulled manure injectors have been around for about 15 years. But that machinery is so heavy that the teams of horses or mules that do the work on Plain Sect farms wouldn’t be able to budge it.

So the Lancaster County Conservation District commissioned the design and construction of a manure injector that could be hauled by farm animals. Built by ELS Manufacturing with funding from The Campbell Foundation, the result is a lighter, downsized version of traditional injectors. It is now available for rent, and the Conservation District is offering farmers $50 an acre to give it a try.

The district hopes to entice Plain Sect participants by showing that injection will save them money, reduce nuisance odor and fly complaints, and lessen their environmental impact.

The Campbell Foundation’s Alex Echols made his pitch to a couple of dozen Amish farmers at an October demonstration of the injector on an Amish farm.

“My belief is, if it doesn’t make money or reduce your burden or make life easier, then why are you going to go to the trouble to do something different?” Echols told the farmers in an open-air barn, while crickets buzzed outside.

“We think there are significant improvements in yields and forage quality. But we want to prove it. Eventually, it has got to be word of mouth.”

The swath of the spreader is 15 feet instead of 50 feet. The hose that carries pumped manure from storage facilities to the injector, called a dragline, was made shorter to reduce the weight of the device. But it could be an attractive alternative to traditional tanker spreaders that require farmers to make numerous back-and-forth trips to collect manure, compacting the soil on each trip.

With a team of eight horses or mules, the injector won’t dispose of the manure as fast as a horse-pulled dragline surface spreader. But most Plain Sect farmers use tanks and have to go back and forth for refills. At a burial rate of 20,000 gallons an hour, the new injector would deposit manure faster than a tank-fed spreader.

And by getting more nutrients to stay in the ground and closer to plant roots, farmers need less commercial fertilizer and save money.

Eliminating malodors from standing manure is becoming more and more an issue in areas such as Lancaster County, where development often butts up against farms.

“Odor is a tremendous issue with neighbors. There is almost no odor when it is injected,” said Rory Maguire, an assistant professor of crop and soil environmental sciences and Extension specialist at Virginia Tech, who has co-written several studies that endorse manure injection.

According to two field tests of manure injection Maguire was involved in, when manure was injected underground and did not run off, the soil held about 50 more pounds of nitrogen per acre in a growing season. That’s a significant cost savings from having to buy commercial fertilizer.

Moreover, by injecting the nutrients below ground, they are immediately placed where roots will be. That has increased crop yields in some studies. For example, a Penn State study found a hefty 27% yield increase in silage crops. And protein content was higher, making it more digestible for dairy cows.

One caveat: In fields where heavy concentrations of manure have been applied in the past and nutrients continue to saturate the ground, yields stayed about the same, said Leon Ressler, a Penn State Extension agronomy educator, who has promoted manure injection in Lancaster County.

And, of course, there are the considerable environmental benefits of keeping manure below ground and out of waterways. Ressler suspects that the manure-runoff problem weighs on Plain Sect farmers more than some people think it does. “People don’t want to be polluters,” he said.

Manure injectors have been improved over time to handle rocky soils and to minimize soil disturbance on no-till and cover crop fields. So far, manure injectors only work for liquid waste and are not yet ready for poultry litter.

Both Maryland and Virginia have state-funded cost-share programs to increase the use of manure injection. Sustainable Chesapeake has paid for manure injection on 121 farms in Pennsylvania, Maryland and Virginia. Seventeen custom applicators offer injection services in the watershed. The Maryland & Virginia Milk Producers Cooperative Association encourages its member farmers in Bay states to try manure injection.

Advocates think the new injector for Plain Sects will advance interest in the conservation practice and help reduce Pennsylvania’s flow of harmful nutrients into the Bay.

Ressler noted that no-till planting started slowly among Plain Sect farmers but is now standard among them. “I’m expecting we will likely see a pretty high adoption over time,” he said of manure injection.

“The forage results are there. It’s just changing the mind-set,” said Jeff Zimmerman, a custom manure applicator.

Elam Stoltzfus, whose Amish company, ELS Manufacturing, built the horse-pulled manure injector, agreed. “It will be a little slower and take a little longer, but if there are benefits, they are going to do it.”

Ad Crable is a staff writer for Bay Journal, where this was first published.