Proper manure application key to preserving nutrients, controlling erosion
MANAWA – Although manure provides valuable nutrients, especially nitrogen, to high N-requiring crops such as corn, proper application is key to keeping those nutrients in the soil while reducing soil erosion.
Methods of applying manure into the ground without significantly disturbing the soil were presented to area farmers at the recent summer field day sponsored by the Waupaca County Forage Council.
During the morning presentations, speakers noted that a large portion of nitrogen, about half in typical liquid dairy manure, is in ammonium or urea form and can potentially be lost to the air as ammonia if the manure is not incorporated into the soil promptly.
Historically, tillage has been the most common method of incorporation, but tillage and, to a lesser extent, standard injection reduce crop residue cover, leaving the field more susceptible to erosion.
A common goal among producers is to find new methods for applying liquid dairy manure to maximize manure N availability while maintaining crop residue cover for erosion control.
Practices at Brickstead Dairy
One of the field-day presenters, Dan Brick, of Brickstead Dairy near Greenleaf in Brown County, has become an active conservation leader, who’s committed to finding solutions that maintain environmental quality while improving soil fertility.
Through the Natural Resource Conservation Service (NRCS) Environmental Quality Incentives Program (EQUIP), Brick invested in an additional 2.9-million-gallon concrete manure structure to contain manure and milk house waste through the winter until it can be spread safely as fertilizer in the spring on his 900 acres of crop and hay ground.
He noted that unlike traditional applications, where the manure is incorporated by cultivating the land, low disturbance manure applications either consist of broadcasting or surface application. However, surface application is susceptible to nutrient loss through surface runoff.
No-till and cover crops
Cover crops also are a key part of Brick’s overall conservation plan to reduce soil erosion and keep nutrients on his cropland.
Two years ago, he switched to a no-till system, and is planting cover crops, like wheat and rye to help keep the soil in place over the winter. “Cover crops utilize phosphorus, build up organic matter, and improve water infiltration and holding capacity of the soil,” he stressed.
Last year Brick planted corn on one of his fields and spread liquid manure at a rate of 10,000 gallons per acre on it the next day. He uses a low-disturbance and low-impact manure application system that applies the manure about 2 inches above the ground.
“We’re not disturbing the soil and we’re increasing infiltration,” he said. Odor reduction is another benefit. “The odor really gets knocked down because we’re not broadcasting the manure all over the place.”
In October, 2016, Brickstead Dairy experimented with the Bazooka Farmstar low disturbance manure applicator in a diverse mix of cover crops. “By injecting the manure directly into the soil, rather than broadcasting, we are giving the cover crops a greater opportunity to keep the manure in place, so it stays on the field,” he stressed.
After lunch at the Bear Lake Resort, the 90 field-day attendees moved to the Dan and Ruth Boerst farm west of Manawa where the couple milk more than 140 cows and raise alfalfa, corn, soybeans, rye and other crops on 400 acres.
On a field where rye had been recently harvested, several methods of applying manure were demonstrated.
In the first demonstration a tanker broadcast the liquid manure and laid a wide swath on the surface of the soil.
On its second pass, the tanker’s operator injected the manure directly into the soil, but leaving the ground looking almost like it had been tilled and exposing much of top soil to potential erosion.
The final demonstrations feature low-disturbance application equipment from Bazooka Farmstar Equipment of Washington, Iowa, which was formed in 1976 from the merge of Bazooka Grain Handling Systems and Farmstar Manure Handling Systems.
In its 110,000-square-foot manufacturing facility, the company produces complete manure injection systems for both tank and dragline applications.
Both systems were demonstrated, clearly illustrating the effectiveness of getting the manure into the ground, while reducing odor and minimizing soil disturbance.