Pa. examines benefits of injecting manure into farm fields


Contributing Writer

LANCASTER, Pa. — Pennsylvania is looking into new ways to deal with the old problem of manure. This year, Pennsylvania is using a $225,000 federal grant to study the benefits of injecting manure into farm fields.

Study purpose

The purpose is twofold: To see if farmers receive better fertilization from having manure injected, and to reduce on-the-farm odors. Penn State Cooperative Extension and the National Resource Conservation Service are conducting experiments on farms in five Pennsylvania counties to study the benefits of manure injection.

Farmers in Berks, Lancaster, Fulton, Dauphin and Bradford counties are participating in the program. For three years, haulers will inject the manure on select fields, where soil scientists and crop experts will monitor soil health and fertility.

More expensive

While the injection process is more expensive than traditional spreading, scientists believe farmers could save on reduced fertilizer costs, said Jeff Graybill, an educator with Penn State Cooperative Extension in Lancaster County.

At the same time, injecting manure reduces run off and nearly eliminates the problems associated with odor, Graybill said.

That is crucial as Pennsylvania faces federal mandates to reduce the amount of farm runoff entering the Chesapeake Bay watershed, Graybill said.

“We need to reduce the amount of nitrogen and phosphorus that is getting into the bay,” he said. “This is one way that we are looking to meet that goal.”

Scientists are targeting dairy farmers for the pilot program because they have a ready supply of liquid manure that is easily inject into the soil, Graybill said.


Participating haulers are using a system that slices a small slit into the soil, injects the manure about 4 inches deep, and then pushes sod back over the hole, Graybill said.

“The things we looked at is how did it affect growth, and did it make things difficult to plant,” he said. “Their planters did a good job in that respect.”

Saving nitrogen

Farmers can lose over half of the nitrogen to the air when it is spread on the surface, Graybill said. However, through injection, farmers are saving 80 percent of the nitrogen, he said.

That means a farmer could use about 5,000 gallons of manure by injection, rather than 7,000 gallons for fertilization, Graybill said.

“We can put on less manure per acre and get the same fertilizer advantage,” he said. “We are using it more efficiently.”

One drawback to injection, however, is that haulers have to charge farmers more because the process takes longer, Graybill said.

Hopefully, any increased cost for the hauling will be offset by savings in fertilizer costs, he said.

“The farmer needs to see the benefit,” he said.

In every case, farmers that are participating in the program practice no-till agriculture.

“We are trying to marry the benefits of no-till with the environmental benefits of injecting manure so you don’t have the odor issues or environmental problems with runoff,” he said.

No-till agriculture is starting to catch on in Bradford County, because the practice helps farmers work more efficiently on an already shortened growing season, said Mark Madden, an extension educator in Bradford County.

However, broadcasting manure onto established cover crops is not the most effective way to deliver fertilizer to plants, Madden said.

This fall, after farmers have taken off their corn for forage, manure injectors will visit as many as 20 farms for the experimental program, he said.

Brian Garman, a Lancaster County dairy farmer who milks about 50 cows, said he has seen no difference in his crops since the injection.

Nitrogen levels

However, during the initial application, Garman said he noticed high nitrogen levels in the soil. That concerned him because that might kill off earth worms, which are important for overall soil health, he said.

Still, Garman said he is interested to see the overall results of the study because he likes incorporating manure into his fields to help with crop growth.

“It is a good source of fertility,” he said. “I prefer that over commercial fertilizer because it has more organic matter in it.”


Up-to-date agriculture news in your inbox!


  1. Darrin, thanks for the info about Jeff Graybill and Penn State. Here’s a link to a short video with Michigan State agronomist Tim Harrigan, showing the benefits of injecting manure while seeding the cover crop.

  2. 80% savings on N? The 09-10 PSU Agronomy guide lists N availability for swine for same day incoperation as 70% and other as 50%.

    High N kill worms – I believe the high salts in the manure kill the worns, not N

    I believe Graybill has it mostly corect. Injecting in PA (Lancaster) is old hat,a common practice and known benefits and drawbacks. I don’t see why the Feds need to spend $255,000 to study something that NRCS and PSU have already studied and researched through the years.

Leave a Reply to lastboyscout Cancel reply

We are glad you have chosen to leave a comment. Please keep in mind that comments are moderated according to our comment policy.

Receive emails as this discussion progresses.