Content ID


High-tech manure

With draglines and on-the-go sensors, livestock fertilizer hits the fast track.

New innovations and technologies have transformed manure applications. A waste product no more, this organic fertilizer is part of many farmers’ crop plans. Here are ways the manure business has joined the precision ag movement.

Variable-rate technology

Two years ago, John Deere released HarvestLab 3000, which uses infrared sensors to analyze liquid manure, providing real-time values for nitrogen, potassium, phosphorous, and dry matter content. Operators can adjust the gallons applied per acre based on nutrient values shown on the display in the tractor cab. Using JDLink Connect, data can be sent to the John Deere Operations Center for mapping and documentation, or shared with crop consultants.

HarvestLab is starting to take hold in eastern Iowa, according to Carrie Keppy, owner of Agriculture Resources, Davenport, Iowa. She works with pork producers on manure management plans and says HarvestLab provides them with nutrient analysis right in the field.

“It’s an exciting opportunity. More of my clients are using variable-rate technology, whether it’s seeding or commercial fertilizer applications,” she says. “Everybody’s trying to not throw money away if it’s not going to provide them some returns.” The old system of taking manure samples from the pit and mailing it to a lab can be problematic, says Keppy. “Anything that gets the manure sample from the pit closer to in-field application is great, if it’s accurate.”

Accuracy is the key. On-the-go testing of manure is new and interesting, says Troy Peterson, but “I still believe a certified lab is better. If the equipment is not calibrated right, are you getting an accurate sample?”

Peterson is a certified crop adviser in northeast Iowa, 20 miles from Minnesota and Wisconsin. The tough terrain in his area, with hills, creeks, and sinkholes as part of the Karst topography, is a challenge. He worries that if HarvestLab tells a grower to ramp up the manure application rate, it may cause issues with the DNR and nutrient plans.

“That makes me nervous. How are you going to be able to defend that with the DNR?” says Peterson. Once the technology is fine-tuned and consistent, he’s all for it. “Some days it’d be nice to know real-time samples.”

Over the past five years, the manure industry has gone from a few pioneers in variable-rate technology to the practice becoming widespread, says Andy Scholting, founder of Nutrient Advisors, West Point, Nebraska. “We have customers who use variable-rate manure as a soil amendment rather than a fertilizer to truly change a farm and its productivity from an organic-matter standpoint. We can variable-rate apply very dry, composted manures and swine manure on a nitrogen-basis,” he says. “There is a lot of technology moving and shaking all the time, but we have finally arrived in the manure sector on an even keel with commercial fertilizers and chemicals.”

A red tractor pulls a full manure spreader over alfalfa ground

On the solid spreader side, the advent of real-time weight displacement has integrated a scale weight-bar system with an automated rate controller, says Scholting. “Instead of guessing at what our density is, we can rely on the scale telling us how much product is leaving the machine.”

The technology is much like a flow meter in a liquid system, a technology that has been around for 30 years, he explains. “But we finally have accurate enough scale systems that we can measure the real-time weight displacements and then vary our rate across the field.”

Houle manure application pulled by a John Deere tractor

The technologies that control liquid manure applications continue to be refined. One of the biggest advancements on the machinery side has been vertical tillage injection, says Scholting. This injection system gets away from the old knife-type application bar and takes a lot less horsepower to run.

“Operators can reduce application rate and cover more ground in a lot less time. We can control liquid application systems just like farmers can control their fertilizer or chemical systems,” he adds.


The second big trend in the manure business is the boom in draglines. A huge concern for farmers is field compaction, and draglines have a big benefit there, says Del Johnston, owner of 5J Farms and Services in Story City, Iowa. “There is no question that in the spring there are advantages over tanks as far as compaction, but there are disadvantages,” says Johnston.

"Technology continues to improve, but in the past draglines had a reputation for not being able to get pit levels lowered as much as pumps used in a tank system." Mileage is another factor. How far do you want to reach with the dragline? How many culverts and how many neighbors’ fields do you have to go across?”

Johnston says he has clients using spring manure applied with a dragline that are getting yields better than they ever have before. “If you are applying within 1 mile of the livestock barns, everything usually works well,” he says. “With booster pumps, I know of dragline outfits that will pump up to 4 miles, so it can be done. That’s just a lot of hose laid out and a lot to monitor.”

Where draglines really have application, he says, is with dairy lagoons where the legal rate might be over 20,000 gallons to the acre.

Because liquid swine and dairy manure is 90% water, the cost of logistics to move it is crippling, says Scholting. “We are limited on how far we can go, which means we have to do an excellent job of siting new livestock to make sure we can maximize the return from those nutrient resources.”

Know your micronutrients to avoid yield plateau

If you are not seeing the yield bump with manure you once were, you aren’t alone. “We’re seeing a plateau in yields for a lot of guys,” says agronomist Adam Cook, Agronomic Solutions, Newell, Iowa. “Manure is an imperfect fertilizer and there may be nutrient imbalances.”

Sample your manure for micronutrients. “Take into account yield and crop removal, and then be ready to add additional nutrients beyond the manure in order to get what the property needs,” says Cook. “There is no 100% perfect fertilizer out there.”

Instead of taking a soil sample every 10 acres, Cook uses a 2.5-acre grid. “We want guys to go smaller, especially if there might be a pH issue in the field,” he says.

Del Johnston uses a soil probe to take a soil sample

Soil tests can be done any season (you can even drill frozen ground for a sample), but pick a season and stick with it for year-to-year comparisons, he says.

Pork producers are getting a better handle on exactly what to feed and when, says Keppy, and that alters the end product. “Instead of feeding the same ration throughout the pig’s life, they’re dividing it up so that they’re covering what the pig needs instead of overdoing it on one phase or another. If you change your feeding regime, you’ve got to be taking some samples to see how it changed with the manure analysis.”

Phosphorus levels have changed the most in the past few years, says Keppy.

“Guys that used manure 25 years ago love to complain about the hog manure today,” says Cook. There’s often not enough phosphorous in hog manure today to last for corn and soybeans in a two-year rotation, he explains.

Manure from pig nurseries, for example, has a lot of zinc and not enough phosphorus.

Crop farmers that use dry poultry manure can have high phosphorus and have to supplement potassium, Cook says. “Some farms realize they need to swap poultry and hog manure on fields to get more phosphorus or more potassium.”

The new wave of contract Costco chicken barns in Iowa and Nebraska means more poultry manure is available.

He tells crop farmers to take several complete soil tests and know what the micronutrients are. “Almost every field with a history of manure is deficient in a micronutrient,” says Cook. “By fixing that issue, you can get past that yield plateau.”

Cook does early crop sampling in May and a nitrate test, which is a 12-inch-deep sample, in June. “The only legal way for people who put a full rate of manure on to be able to apply additional nitrogen is if that test shows they need it,” Cook says. Throughout the summer, he does tissue testing for growers. In the fall, his team is in the field sampling as soon as the crop is harvested.

“We’ll analyze that data and set the plan for the proper rates. If there hasn’t been manure on that ground for a long time, there’s a high probability of a benefit showing up.”

For the best manure samples, Cook dips a PVC probe into pits at each end of the barn in early September. For solid manure, he digs in with a shovel or a loader bucket, taking a scoop from the top, a scoop from the middle, and a scoop from the bottom. Stir that up in a bucket and then reduce that to the sample size.

To make sure the samples stay cold and there is no nitrogen volatilization between the barn and the lab, freeze them before shipping. “The last thing you want is a liquid manure jar that gets hot in the UPS truck and explodes,” says Cook.

Digesters and composting

Two other topics trending today are digesters and composting, says Andy Skwor, agricultural services team leader with Wisconsin-based engineering firm MSA Professional Services. Digesters are coming back on farms because of the compressed natural gas markets and California’s Low Carbon Fuel Standard, he explains.

Andy Skwor headshot
Andy Skwor
Photo credit: Andy Skwor
Some farmers do anaerobic digestion, providing manure to a digester company. There are advantages from a renewable energy perspective. “Natural gas production is where the advantages are today, primarily because there isn’t enough profit in the power purchase agreements to continue doing electrical generation. Utilities are just not renewing power purchase agreements,” Skwor says.

Composting is getting more attention from farmers, too, he adds. “There’s so many advantages, with purchasing less commercial fertilizer, controlling erosion, water retention, and nutrient retention,” Skwor says. “All the things compost can add back into soils are advantageous environmentally, whether you’re a livestock farmer or grain farmer.”

However, composting on a large-scale basis requires a significant capital investment. “Composting technology needs to bring costs down, but it has shown a lot of promise moving forward,” he says.

Keeping it clean

Keeping up with shifting regulations about manure management is a challenge. “Regulations are a moving target. Local control of groundwater is ratcheting in what we can and can’t do,” says Scholting. “Everybody wants clean water, but we have to find middle ground to make sure our producers can operate the way they need to while maintaining resources.”

In the past 20 years, Keppy has seen farmer attitudes change from complaining about regulations to accepting them. “It’s been a shift in mentality to where they are focused on using the manure efficiently and wanting to do the best job they can with the nutrients.”  

There is no reason for farmers to overapply nutrients, says Scholting. “We have no incentive to put a pound of phosphorus or nitrogen on an acre that doesn’t need it. The public perception is that any industry is incentivized to pollute unless they are regulated. The power of the dollar and the value of these nutrients does an excellent job of regulating how we apply them because nobody wants to waste a good resource.”

Most of his clients leave room for commercial fertilizers with their manure applications, says Scholting. He gathers data and puts together a crop plan that supplements other fertilizers. He meets with client in the spring to “make sure they understand what their crop plan is and fully understand all of the credits they have from their manure applications so they don’t go out in April and May and overapply nutrients and buy more than they need.”

A John Deere tractor pulls a liquid manure tank over a field with hog confinements in the background
Photo credit: National Pork Board

There is no greater synergy in agriculture than the relationship between the livestock sector and the grain sector, adds Scholting. “It is an awesome symbiotic relationship that the crops feed the livestock and the livestock feed the crops,” he says. “If a grain farmer is farming around livestock and isn’t using manure, he needs to not miss the boat because he can get those nutrients at a discount and improve the profitability and productivity of his farm.”

Manure has the power of organic matter, especially in areas that have lower organic matter soils. “Farmers buy nitrogen or phosphorus, but manure is the whole package,” he says. “With the micronutrients, farmers often see a tremendous yield advantage beyond what they can do with commercial fertilizers.”

Manure brokers are a growing segment of the industry. Nutrient Advisors has a manure marketing brand, StrongField Resources, for clients who need to market their manure product. “They put their manure in our portfolio and we market it,” he says. “Manure marketing and brokering is a whole other piece to the greater puzzle. We are bringing the crop farmer and the livestock farmer together.”

Keppy sees less of a divide between crop farmers and livestock farmers today, because both recognize the value of the manure. “The crop farmers recognize the value of the manure for the moisture-holding capacity of the organic matter that it provides the soil,” she says. “The micronutrients have a huge impact on their cropping system from year to year.”

What is the value of manure?

All manure is not the same. In general, dry and concentrated poultry manures have the highest value, according to Andy Scholting, founder of Nutrient Advisors, West Point, Nebraska. “Comparatively, liquid dairy manure on a pound-to-pound basis is going to be some of the weakest manure, but we can apply a lot per acre,” he says.

Dry poultry litter is extremely consistent, says Scholting. “We can transport it up to 100 miles and it still pays to do that. Comparatively, with beef manure we are battling the mixing of dirt and water, and we find inconsistencies. Part of our consulting with beef clients is doing the things they need to do on the feed yard to achieve the best consistency they can so they have a salable fertilizer product or they can depend on it on their own farm,” he adds.

Over the past 20 years and thousands of manure samples, there is consistently about 48 pounds of nitrogen, 30 pounds of phosphorus, and 40 pounds of potassium, plus 8 pounds of sulfur per thousand gallons in hog manure, according to Troy Peterson, certified crop adviser. There is also some boron, copper, calcium, and iron.

“Some agronomists are not embracing manure as a source of fertilizer as much as they should be,” says Peterson. When he writes manure plans, he leaves room for growers to supplement nitrogen. “That’s a nice carrot to give that crop a little shot to gain another 30 bushels. They can spray chemicals and then throw nitrogen over the top to balance the crop.”

According to Adam Cook of Agronomic Solutions, “As hog producers became really efficient at feeding the animals, the nutrient content has dropped over the last couple of decades to the point that it can be more expensive per pound of nutrient to apply it.” With sow farms and nurseries, “the livestock producer is pretty much guaranteed to have to eat that cost. The finisher is still a net value of the fertilizer versus the cost of application,” he says.

Read more about

Crop Talk

Most Recent Poll

To meet my machinery needs in the next year, I’m

holding off on buying and working with what I have
43% (33 votes)
I just want to see the responses
28% (21 votes)
looking online for deals
13% (10 votes)
sticking to my dealership
9% (7 votes)
hitting the auction market
7% (5 votes)
Total votes: 76