Home Forums Hunting & Shooting Hunter's Campfire Designing a better cow manure

I'll bet you didn't know that some people make a study of manure. We have over a half million dairy cows within 75 miles of here, and cheese and yogurt factories to process the milk. As you can guess, the amount of manure produced is very large and it very hard to dispose of. We have a number of compost operations around the area but most is spread on the land. However, there's only so much you can spread on the land without destroying the soil.
Here's an interesting article on how researchers are trying to 'custom design' manure by manipulating the feed that goes into it.


Designing a Better Manure

TWIN FALLS � �What goes in, must come out� applies to dairies as well as thermodynamics.

Researchers are beginning to put that principle to work to help create �designer� manures to prevent build up of macronutrients in the soil, but feed costs will limit how widely the practice is adopted.

Most nutrient plans written for Idaho dairies are primarily concerned with nitrogen and phosphorus levels, but other macronutrients can also be a concern. Calcium, magnesium, potassium and sodium are all macronutrients whose levels in manure and urine can be influenced by feeding practices.

Cows need calcium for many of the same reasons humans do, but feeding cows more calcium doesn�t make the milk they produce more calcium-rich. Instead, the amount of calcium in the feces increases. That�s also true when magnesium levels are increased in rations.

Increasing potassium and sodium levels, which are both salts, increases the concentration found in urine but also does not impact milk content, explained Rick Norell, University of Idaho extension dairy specialist in eastern Idaho, during the UI nutrient management conference held last week.

A study of 39 large dairies in California found that all of them were feeding calcium, magnesium, potassium and sodium at levels above National Research Council (NRC) recommendations.

That�s partly because the NRC recommendations were published more than two decades ago and cows are more productive today and require more nutrients.

But it�s also because dairy rations are not exact formulations, Norell said. Nutritionists formulate rations to meet the energy requirements of lactating cows, but aren�t as concerned about about minerals such as calcium.

However, dairies are becoming more concerned about buildup of macronutrients � particularly salts � in soil where manure is often applied. To track macronutrient levels, Norell recommends testing loads from major suppliers and those feedstuffs that have the greatest variability in macronutrient content.

He wouldn�t bother to test salt or bicarbonate fed to dairy cows but those products come with a guaranteed lab analysis. Forages, on the other hand, vary dramatically in terms of macronutrient content.

If salt buildup is a concern, dairies should avoid feeding free-choice mineral and instead force-feed salt to give cows what they need. If a dairy does decide to offer free-choice salt, provide a block rather than granular salt. Studies have shown that cows eat twice as much granular salt as they do salt from a block.

While ration formulation can impact how much manure or urine is produced and what the macronutrient content of that manure is, how dairies handle the manure is also important.

Soluble salt concentrations, for example, are much higher in solid manure from dairies that scrape manure. But concentrations are highest in the primary lagoon on flush dairies.

Because lagoon water cannot be transported as far from the dairy as solid manure can be, the potential for increasing salt levels in fields where lagoon water is applied is greater. Corn can tolerate higher salt levels, but beans and potatoes are more sensitive.

Howard Neibling, UI extension water management engineer, believes dairies should be more concerned about salt levels in urine and manure. The only way to reduce high salt levels in fields is to leach the salts through the root zone, which also moves other nutrients.

Dairies are concerned about salt levels in soil, Norell said, but they are more concerned about managing feed costs.

�They are not going to balance rations for macronutrients now,� he said. �The chance to make an improvement is driven by the need to make an improvement.�

Calcium, magnesium and sodium are already highly variable. Limestone is calcium carbonate. Dolomite is a combination of calcium and magnesium carbonate. Hard to imagine them causing problems provided there is sufficient organic matter to provide pockets of lower pH to supply those elements that are bound up by high pH.

Potassium really is considered a macronutrient and plants will engage in "luxury consumption".

They ought to spread some of that natural fertilizer on California golf courses. They love that organic zhit!

Our soil here is alkaline with a pH averaging about 8. The ground and surface water are about the same. We have an overabundance of Ca and lime is the worst thing you can do to a lawn or garden. Farmers feed Ca for milk production and a lot of it ends up in the manure. There's no easy fix.

Sounds like a lot of bovine scatology to me!

When y'all figure out "better manure", please send the results to 1600 Pennsylvania Avenue, Washington, DC. It seems all we get out of that location is bullchit by the metric ton, and all of it of the lowest grade.

So Rock Chuck, what is the preferred method of the big dairies around Twin for dealing with manure? I see the big dairy operation off highway 84 (heading toward Jerome, on the left) and it looks like they compost. Is that the preferred method or do most haul or pump to the fields? Just curious. Hauled a lot of cow [bleep] in my youth in a little 175 bushel IH manure spreader. Cow manure definitely the bain of any dairy farmer's existence 'cause those cows produce so much of it.

seems like the preferred method was pouring it into the irrigation canals while no one was looking...... The EPA frowns on that, as a couple of them found out!

Well, back in the day, the flush from our milk barn (60-70 cows milked night and morning)went right into the creek in front of our dairy. That crick was full of muskrats and rats, frogs and birds. The rats and birds seemed to really like the grain that got washed down. We'd flush the parlor and the holding corral night and morning with a big, 2" hose with water under good pressure. Didn't seem to harm anything.

Jordan

Erath Co. Tx. has always been big dairy country. Waco Tx. about 100 miles downhill from here says our cows ruin their drinking water. I don't know.

The regional difference is interesting. As I was reading, I wondered why they were concerned about salt. Here in Pa. the big problem is phosphorous buildup and runoff. Then I realized you don't get near the rainfall we do so saline soils and the high pH levels are a problem we don't have.

There is a lot of research going into handling manure. We've got some digesters in the state that make electricity, then have a smaller amount of solids to deal with. Composting is another option as is drying/recycling the solids for bedding. Although that still leaves the liquid with the salts to deal with. It's too bad it isn't as easy/cheap to ship manure as it is to ship grain. That's the real problem, nutrients come from the grain farms and it's not feasible to ship them back to the grain farm in the form of manure.

There are serious fines and penalties for discharges to streams, just heard about a guy that was bringing in a dozer to scrape diversions in his frozen, snow covered fields because the manure he spread on snow covered ground was running down towards the stream.

Dale

Along the same lines a coworker had the pleasure of starting off with scientist that assessed dietary composition via microhystological examination of ground up crap. One can shake out specific plants by the distint size/shape/etc of undigested cell walls. Early on they found ground sloth and cave bear poop in some arid caves, conducted their analyses, and then reported the results.

Title of the first paper: 25,000 Years of the Same Old Sh-t.

A major alfalfa seed company is coming out with a GMO alfalfa that has less lignins, higher digestibility, and produces less manure while providing a higher RFV.

Some of the more progressive dairies have experimented with digesters to cook it into methane for fuel. That's an expensive project, though, so not many have done it. There are a number of compost operations going. They ship it all over the place to commercial nurseries and landscapers. I've been told that the one you've along I84 gets manure from a number of dairies to compost. Over all, though, it's a big problem. The law regulates how much they can put on the land to protect the soil and ground water. Some dairies have bought out farms just to have a place to spread it.
I can tell you this - if you buy property around here, if you're smart you'll get on Google maps and carefully study the aerial photos of everything around the land you're looking at. Dairies are easy to spot on an aerial. You really don't want to buy anything east of one.