Manure Manager

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Not a Day at the Beach

Early sand bedding use at a Michigan dairy operation might have felt like a day at the beach for the cows but for the operators, it was anything but. That is until they received some help from an equipment manufacturer and Michigan State University.


Nobis Dairy Farms helped develop a sand separation system that helped other dairy farms. Photo by Contributed

The cows were immediately more comfortable and healthy when Michigan-based, Nobis Dairy Farms switched to sand bedding in their milking barns in 1974. However, handling and recycling the sand-laden manure – that was another story and took a while longer.

By working with sand separation equipment manufacturer McLanahan Corporation and Michigan State University, the dairy helped to develop a proven sand and manure separation technology that has now made it considerably easier for other dairy farms to recycle sand bedding while reaping the benefits.

For their leadership in this area of manure management and other measures taken by the dairy to minimize their impact on the environment, Nobis Dairy Farms was awarded the 2015 Outstanding Dairy Farm Sustainability distinction by the Innovation Center for US Dairy.

About Nobis
The dairy farm is located north of Lansing, near St. Johns, Mich., and is owned by Ken and Larry Nobis. The dairy manages a total of 1,060 milking and dry cows, with seven barns on the home site. Five are free stall barns using sand bedding. The dairy also has replacement stock housed in different locations within four miles of home.

Larry says the herd is at a comfortable size right now and they have no immediate expansion plans, given the current, worldwide oversupply of milk. They are leaving it up to Ken’s son, Kerry, who is the dairy’s herdsman and next generation dairy farmer in the Nobis family, to decide how large the herd might grow in future. Both Larry and Ken are still very active in the dairy and Ken is the president of the Michigan Milk Producers Association.

They have used sand bedding in all their free stall barns since 1974, but it was not until 2009 that they actually began recycling the sand. Previously it was simply land apply along with the manure for disposal and for the nutrient value offered by the manure mixed into it. They use chopped soybean straw for bedding in their heifer facilities.

The entire farm operation involves both operating a dairy and growing feed and cash crops on 3,000 acres. As a percentage, Larry says adding the sand to their cropland prior to installing their sand recycling system was not significant. They were careful with how much they land applied per acre with regular soil testing. Although it did not seem to have an adverse effect on their cropland, he adds that he would not recommend this practice over a long period of time. Now, the sand is recycled, which has made their manure management system a lot easier to handle.

The past
Prior to making the switch to sand bedding, the dairy was using organic material and sawdust. Larry says using the organic bedding was causing the dairy some problems with two areas of concern on any dairy farm, which are elevated somatic cell count in the milk and mastitis in the cows.

“It wasn’t anything serious but we’d heard reports of sand being used in other places, and that sounded really good,” Larry says. “So we put some sand in the free stalls, and we couldn’t believe how comfortable the cows were.”

He adds that because it is an inorganic material, using sand bedding helped to keep the somatic cell count in check and it really reduced mastitis incidents.

“Using sand for bedding, it’s wonderful for the cows. It’s like they are having a day at the beach every day,” Larry says, “but it did make handling manure very miserable and offered us a lot of challenges.” For the first couple of decades when the dairy used sand bedding, he adds that there wasn’t a lot by way of equipment to allow them to recycle sand-laden manure. However, they felt that someone would eventually come up with a solution.

“And they did,” Larry says. “There are several different pieces of equipment and technology out there where you can separate and recycle the sand, so that you handle the manure as manure.”

But it wasn’t so easy in the 1980s. He says the challenges started to mount as the herd started growing in size. They installed a cement storage pit that provided them with four months storage capacity for their sand-laden manure, but as it is apt to do, the sand sunk to the bottom and did a number on several pumps designed to pump manure and not abrasive sand.

“We’d wear out manure pump after manure pump and we’d be welding them all the time. Then there was the sand settling out in tankers before they had circulating features,” Larry says. “It was a mess and very trying.”

By the end of 1980s, they realized that something had to improve with handling the sand-laden manure, and it started with a meeting that involved their manure disposal contractor and researchers at Michigan State University. By this time, more dairies were using sand bedding and they were experiencing the same problems as Nobis Dairy Farms.

The challenge
They challenged Michigan State University to help find a solution, and this is when equipment manufacturer McClanahan Corporation entered into the picture. They were able to make modifications to equipment they were already supplying to the mining industry to separate the sand from manure.

“We’re very comfortable with our McClanahan system and it has worked very well for us,” Larry says.

He says it fit well within their established farm operations, it stockpiles just enough sand for just-in-time reuse, and the system seems to minimize odor from the farm. He estimates that the dairy is saving $80,000 to $100,000 per year being able to recycle its sand, and when all the benefits are factored in, the system will probably pay for itself in about five years.

Another financial benefit is having access to this separated out, organic fertilizer resource, although they haven’t calculated the exact benefit versus having to purchase synthetic fertilizer.

“I do know that our fertilizer costs are minimal compared to a cash crop operation,” Larry says.

The system
A Bobcat with a rubber scraper attachment cleans the free stall barn alleys three times a day, dumping the sand-laden manure into a reception pit. A Houle piston pump sucks the material collected in the reception pit for processing through the McClanahan sand separator. While this system has been around for some time, Larry says the reason they delayed installing one at the dairy was because of how much fresh water the separator required.

“We weren’t interested in making a lot of fresh water dirty, but they came up with a closed loop system,” he says.

This system is able to recycle what he called the “clean” dirty water. The manure solids have been removed from the water by processing the manure stream through the sand separator and then through a Daritech rotary screen solid manure separator that removes and piles the manure solids.

The dairy collects this water from the separator, as well as grey water from general dairy operations and water runoff from their feed storage area into a 14 million gallon lagoon. This water is recycled either through the sand separation system, used for irrigation, or land applied as organic fertilizer.

The sand separation system consists of recycled water added to a slow moving and long auger, with the clean sand dropping from the top end of the auger and the solid organic material as well as the water extracted from the bottom end. The sand is stacked for about two weeks and then reused as bedding. The manure solids are separated from the liquid stream, collected and land applied as organic fertilizer, while the water is transported to the storage lagoon, with a portion recycled through the sand separator.

About seven million gallons of liquid is collected from the manure, but a total of 20 million gallons are actually collected by the dairy, when considering all the water channeled and collected in the lagoon from various sources on the farm. A considerable amount of that nutrient-rich liquid is land applied as an organic fertilizer on cropland using a drag hose system. Nobis Dairy Farms carefully manages its crop rotation to maximize its use of the nutrients added to the soil. For example, they will harvest a wheat crop, follow up with a manure application, then plant a forage crop like forage oats, resulting in a double crop from that same field while mining valuable nutrients like nitrogen placed in the soil from the manure. Then they will follow up the next year with a corn crop and also recover corn silage. They soil test every year to ensure that they are not experiencing any increase in their phosphorus levels.

“So far, this method is working very well,” Larry says.

Because the liquid waste stream is diluted, they can apply about 40,000 gallons per acre over an entire year, and typically they will land apply between 500 to 600 acres one year and then the same acreage across the road the next year. Given the amount of land they plant and their manure management method, Larry says the dairy could probably support as many as 3,000 cows.

The solids are land applied using two Knight spreaders as well as a Meyers Manufacturing spreader equipped with vertical beaters and a GPS system for precise application, mounted on a truck.

Conservation
In addition to paying attention to their overall manure management system to minimize environmental impact, Nobis Dairy Farms has also voluntarily established 50 to 100 foot grass buffer strips along their drainage ditches, representing about 70 acres of land that they harvest for feed. This practice mines any nutrients that have gathered in the ground so they don’t seep into the drainage system.

Practices like their manure management method, minimizing odor, and concern for the environment with the extensive use of buffer strips has garnered attention for Nobis Dairy Farms as a leading environmental steward in the U.S. dairy industry.