Cow by-products add fertility to soil
by Willy Klein, freelance writer, Britt, Iowa
Kirk Snitker has a 75-head dairy herd and 305 tillable acres as part of his rural Waukon farming operation. He feeds some of the grain crop to his dairy herd and is becoming more proficient at letting the cows "feed" the crops.
It is a matter of using the manure and parlor wastes stored in a lagoon outside his barns to fertilize his cropland. Instead of just spreading the liquid on any available land, he is studying the nutrient value of the manure and planning ways to efficiently utilize those nutrients to benefit his crops and soil.
Snitker and other livestock producers are getting assistance from Iowa State University Extension as they figure out the best manure nutrient management plan for their own operation. At a workshop, sponsored by ISU Extension and local veterinarians, Snitker combined new information regarding soil and crop needs with manure nutrient facts to make some changes in his application practices.
The workshops are designed to help producers recognize manure nutrients and then to utilize them as adjustments for commercial fertilizer, according to Bill Lotz, ISU Extension crop field specialist and workshop presenter.
"There is no standard manure nutrient management plan," said Lotz. "Each workshop takes on the flavor of the participants as they work on their specific situation with two or three field specialists."
Lotz said that some participants leave with a completed plan, while others leave feeling like they are already doing what needs to be done. Others take the information back to their operation and begin some testing of their own.
Participants who haven't been testing their manure are encouraged to get a current test to replace the book values used at the workshop, said Lotz. For many, that is the next step following the workshop.
Snitker has never tested the liquid manure in the four years he has had his lagoon, but thinks he may test this fall when he hauls.
He was primarily interested in the new recommendations for soil fertility presented by the workshop specialists. The recommendations, coupled with colorized maps showing crop potential, were information Snitker felt he needed.
When he empties the 175,000 gallons of manure from the lagoon and spreads it over approximately 40 acres of his land, he will make some changes because of the workshop.
"I haul to less fertile land that is further away. Now, I can see that it is more affordable to haul a little further to get to the soil that needs the nutrients," said Snitker.
Snitker started taking credit for the manure six years ago, after working on a manure test plot with ISU Extension personnel.
"The first year I took nitrogen credits for the manure and alfalfa, I really cut back on my commercial fertilizer. My Dad just shook his head," said Snitker. "He was pleasantly surprised when harvest came around."
Snitker has always used book values to figure the credits and knows that he still isn't allowing enough credit. He also realizes there is nitrogen loss when he spreads the liquid and does not incorporate immediately, but weather and milking chores sometimes interfere with timeliness.
Injecting the manure, one alternative to losing the nitrogen, is a method Snitker has tried, with the result being a good stand of corn. When deciding whether to inject or spread the manure, he looks at field compaction, where he is in his crop rotation, and being a good neighbor.
Snitker will consider his whole operation, livestock and crops, as he draws up an efficient manure nutrient management plan and continues to fine tune it to his needs.
ISU Extension has planned manure nutrient workshops this winter. Specific workshop information is available at local extension offices.
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Page last updated October 5, 2004
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