Hidden treasure: The real value of manure


BARNESVILLE, Ohio – How much manure are you really spreading? Guesstimates just don’t cut it anymore. A study in the 1990s found application estimates by southeastern Pennsylvania farmers were off by as much as 300 percent.

So you have to calibrate your spreader.

But what’s in the manure that you’re applying? What actual nutrient value is in that black gold?

The total potential manure fertilizer value from all livestock and poultry production nationally is an estimated $3.4 billion each year, according to the Council for Agricultural Science and Technology.

A typical dairy cow produces about 115 pounds of manure every day. Nutrient values range from $45 to $85 for that one dairy cow and her replacements. The actual value depends on type of bedding, animal species, storage facility and method of manure application, among other factors.

The only way to find out what’s in your manure is to get a manure analysis.

And how much fertilizer do your fields need? Only a soil test will tell you for certain.

Fact-finding study.

Ten Belmont County dairy farms discovered the value of their manure during a yearlong manure utilization funded by a $1,607 sustainable agriculture grant through OSU Extension.

“The farms in this study showed an average of $35 per acre savings each year when farmers applied proper amounts of manure,” said Len Snedeker, Belmont Soil and Water Conservation District technician who coordinated the on-farm research.

On a nationwide basis, an average of 15 percent of nitrogen, usually purchased as commercial fertilizer, could be replaced through the use of animal manure. Approximately 42 percent of crop phosphorus also could be supplied this way.

“I think the farmers were surprised at the value, that it’s actually worth money,” Snedeker said. “It’s not just a nuisance.”

Cut fertilizer bill.

Ed Stenger, who milks 70 Holsteins near Belmont, estimates he was able to cut his fertilizer bill by a third this spring, after finding out the nutrient value of his manure and the rate it is being applied.

“I didn’t have any idea how much I was putting on,” Stenger said. “You just don’t realize there’s that much nutrients there.”

The participating dairy farms ranged between 60 and 100 head. Each farm had individual crop fields soil tested to determine nutrient needs and manure samples were taken from each farm to determine available nutrients. Each farm’s manure spreader was calibrated to find out just how much manure was being applied, then a manure utilization plan was developed for each farm. The farms also received a fertility recommendation.

What they learned was surprising.

Numbers vary widely.

Not all manure is alike, not all spreaders are alike and no two fields’ fertility needs are alike.

“I was surprised how much it varied from farm to farm,” Snedeker said.

For example, manure analysis showed variations as great as 200 percent. Total available nitrogen ranged from 4.9 pounds/ton at one farm to 10.2 pounds/ton at another. Phosphorus ranged from 2.7 pounds/ton to 9.2 pounds/ton; and potassium ranged from 4.8 pounds/ton to 14.4 pounds/ton.

Spreaders varied widely, too. One spreader applied 6.1 ton/acre; another spreader applied 27 ton/acre.

Neal Moore, who milks 100 head of Jerseys near Beallsville in southern Belmont County, was surprised at his farm’s findings. “I have one field of hay so high in potassium that it’s almost to toxic levels,” Moore said. “It doesn’t need anything for a long time.”

“Now I know better what to buy, rather than throwing money at the field.”

If anything, the study stirred the milk producers into looking at that manure as something useful, not useless.

“It’s a lot different if you think of manure like fertilizer,” Stenger said. “It’s just like putting fertilizer on.”


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