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Milk works as fertilizer, says preliminary study

Milk works as fertilizer, says preliminary study

Without a way to stop the dairy price rollercoaster, Dave Wetzel has long thought past the bulk tank on his Nebraska operation.

In 2000, his occupation transformed from a steel industry worker to the owner of an O'Neill, Neb. dairy. With grass-based ambitions, he quickly began diversifying the operation to include swine, crops and niche products. Today, Green Pasture Products, Inc. is best known for its high-vitamin butter oil. When combined with fermented cod liver oil, the product is said to be rich in omega 3 fatty acids that provide immense health benefits.

"We've turned back the clock and restored these sacred foods to their roots," says Wetzel on his website. "We are proud to offer these historical sacred foods prepared with the same great care and concern for our generational health as our ancestors."

Though the rare combination first drew attention to southern Nebraska, it was by chance that buzz over Wetzel's management practices made its way to Wisconsin.

When creating butter oil, Wetzel begins with cream from his dairy. The cream is boiled to make ghee. Protein from the condensed milk is then extracted via centrifuge, so that only fats, vitamins, minerals and enzymes remain in a butter oil form. The high concentration of omega 3 oil is marketed, but the skim milk byproduct had little use on the operation after calves and swine were fed.

In 2004, Wetzel dumped the unpasteurized skim milk on his alfalfa and cool-season grass pastures evenly. Within a few weeks, he noticed greener grasses that his herd flocked towards. Not only were cattle drawn to the milk-fed grass, the area showed higher yields while soil core sampling displayed increased ground porosity.

Impressed with the results of his unconventional fertilization, Wetzel quickly contacted University of Nebraska Extension and Certified Holistic Management Educator Terry Gompert.

"When I started looking, there is virtually no research done on this," he says. "I called in some favors from two specialists to put together a replicated experiment."

Gompert's requests were accepted by a pair of researchers at the University of Nebraska. Charles Shapiro, professor of agronomy and horticulture soil scientist, and Stevan Knezevic, herbicide specialist, took on the challenge in 2010. The trio created a summer experiment in conjunction with Wetzel.

The design tested five different treatment rates from zero to 32 gallons of raw skim milk per acre. The different levels were mixed with water so that each 100 foot by 10 foot plot received equal amounts of liquid. Each application was replicated on four plots.

"We determined how much milk to put on by estimating how much a farmer would pay for fertilizer if this really worked," Gompert says. "To make this economically sound, we had to provide something in 32 gallons or less per acre."

Additional variations were created with the use of Wetzel's other byproduct of cod liver oil. Either 4 ounces of oil per acre were added to the milk or the milk was applied separately.

"Essentially 10 different applications were replicated four ways," he explains. "In the test, the skim milk was taken out of the tank, it was mixed and everything was put on the land within an hour. It was very alive material."

The milk and milk mixtures were applied to the diverse grass and legume fields as a foliar application in May with a small pressurized tank.

"Looking down, we could see the drips of milk, so there was a fairly good saturation," Gompert remembers.

The researchers hypothesized that Lactobacillus from the milk would combine with fungi from the fish emulsions to feed active soil bacteria, thus creating a fertilizer source for the irrigated, well-established pasture.

Forty-five days after the application, the fields were harvested and yields were measured. The plots without milk or oil provided 4,454 pounds of dry matter. Fields drenched with 2 gallons of milk yielded 5,578 pounds. The plots with milk plus oil had slightly higher yields, but results were sporadic.

"The highest advantage we saw was at 2 gallons per acre," Gompert emphasizes. "An extra 1,124 pounds [per acre] from one application is quite significant. It's more than we get from adding nitrogen or phosphorous from the local coop."

The team was most surprised that 2 gallons of milk ignited a greater reaction than higher application levels.

"It didn't make any difference if we gave 2 or 32 gallons of treatment," he adds. "Two gallons of milk increased yield by 26 percent; Wetzel cod liver oil increased yield by 20 percent; together, they increased yield by 31 percent. That's on one harvest; we don't even know about the long-term benefits."

The researchers then used a penetrometer to see if there were any differences in soil compaction.

"We did three tests at different levels at each of the plots to see the relative softness of the land 45 days after the application," he says. "Essentially, we did 12 samplings and averaged the readings for pounds of pressure at 6, 12, 18 and 24 inches."

The fields applied with only oil were 9 percent more porous than the plots with no application. Meanwhile, the porosity of plots fertilized with milk was 18 percent softer than the control. The milk plus oil application had too much variation for direct conclusions.

The increased porosity is closely correlated with higher yields and could have long-term affects on plant health, Gompert indicates.

"If we have more porosity, we are increasing water-holding capacity and air," he says. "Those are the two requirements to grow roots, carbon and microbes."

Because the study was conducted by credible experts and showed duplication, Gompert has experienced considerable excitement from dairy and crop producers on all levels.

"I think this will pass the scrutiny of research as far as a study that can be duplicated," he says. "I've gotten a ton of testimonies of farms doing the same thing. It really is exciting."

Still, he says that further research is needed to locate the best raw milk fertilization strategy.

"The data does lead to more questions," Gompert admits. "How often should it be applied and with what method? When is the best time for application? When should the crops be harvested?"

The type of milk used does not appear to be an issue, however.

"We used skim milk on our study, but whole milk seems to work equally well," he says. "It's almost like it doesn't matter what form it's in as long as it gets into the soil. If it turns out to be a microbial benefit, you would want to use unpasteurized milk."

Grazing and fertilization experts at the recent Grassworks Conference in Wisconsin Dells were "cautious to respond" on why milk application enhances soil life or how beneficial the practice could be. They were optimistic that if the practice would work, dairy producers would have an alternate use for their milk in low price times or for treated dairy products.

Because of its feasibility, Gompert says that six universities have expressed interest in performing further milk fertilization studies.

Closest to home, Bill Kolodziej, grazing specialist for Marathon County, is putting his own spin on the trial to see how milk nutrients affect soil life in Wisconsin.

"We were asked last year if we would do a trial with some organic treatments to see if there is any validity to a raw milk, sea salt and Rise-up product fertilization," he says. "Our plans this year are to replicate what Terry (Gompert) did, harvest and do some clippings to see if there is any truth to it."

For producers who are looking to conduct their own on-site trials, it is imperative that they use their milk produced on the operation to comply with state raw milk regulations.

"It's legal in Wisconsin to apply your milk to your crop, but you cannot sell the product without a milk handler's or fertilizer license," says a representative from the Department of Agriculture, Trade and Consumer Protection. 

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