Feature: Searching for a remedy for soil compaction

Wednesday, May 5, 2010

With help from Ontario Pork and the agriculture ministry, a Drayton farmer is looking to tire inflation-deflation technology as a way to reduce soil degradation by farm equipment

by DON STONEMAN

The technology is available to reduce soil compaction from grain buggies, combines, big tractors and other large machines commonly used on Ontario farms today.

Not so with manure spreaders, particularly the large capacity liquid tankers used by pork and dairy producers. Pork producer Jake Kraayenbrink, 47, who farms 300 acres north of Drayton and raises purebred swine genetics, wants to change that.

"Manure is a valuable commodity though it has some strikes against it," he says. The trick is to get the manure to the plants when they need it, without damaging the soil while applying it.  "Many acres get manure applied when the ground isn't necessarily fit." If better ways could be found to spread it, he says, manure would be even more valuable.

The problem is pressure in the tires on manure spreaders. The higher the pressure in the tire, the more pressure is put on the soil.

The pressure soil is exposed to is equal to the pressure in the tire at the time, says Greg Stewart, a corn specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) who monitors test plots on Kraayenbrink's farm. "We know deflating tires really helps."

But farmers want high tire pressures when pulling loaded tankers on the roads at high speeds – 40 kilometres per hour or more. Manure tanks are a challenge, agrees Adam Hayes, OMAFRA soil management specialist for field crops. Road travel is necessary with nutrient management plans requiring spreading further from barns. Low tire pressures on the road make loaded tankers unstable at high speeds.

Through Ontario Pork, Kraayenbrink was able get help to look at variable tire pressure technology via a grant from Agriculture and Agri-Food Canada's Farm Innovation Technology program through the Agricultural Adaptation Council. Kraayenbrink, Stewart and Sam Bradshaw, Ontario Pork's environmental communication specialist, talked to manufacturers in the United States who have the technology to inflate and deflate tires.

"They realized that we were talking about a lot more air than they were used to," says Kraayenbrink.

Internet searches pointed Kraayenbrink towards companies in Europe, where there has been more research on compaction. The Farm Innovations Technology grant paid their costs to travel to Europe in early March to see how it's done. There, they visited several tanker and farm tire manufacturers and talked to agricultural scientists at universities.

Their conclusion is that not only are yields improved but so is fuel consumption.

Bradshaw says French tire manufacturer Michelin reports that farmers can expect a 10.8 per cent increase in yield by using radial tires with lower pressure compared to high-pressure bias ply tires. On top of that, fuel consumption can be cut by 25 per cent.

Kraayenbrink thinks this seems like a lot, but Stewart says "draft forces" were 15 to 25 per cent less using radial tires compared to bias ply, with fuel consumption in the same range.

It's a lot easier to push a low-pressure tire over soil than if it has sunk in, Kraayenbrink explains. Even sinking in one centimetre (less than half an inch) is the equivalent of climbing a one per cent grade, Bradshaw adds.

However, the inflation/deflation technology used in Europe isn't likely to fit with current North American practices and expectations of farmers.

Kraayenbrink says the issue isn't inflating the tires; it is deflating them quickly when a tanker leaves the road and starts spreading in a field. With a typical European system, it takes about 90 seconds to deflate tires to nine pounds per square inch from about
32 psi. A minute and a half "feels like an eternity" for a tanker operator, Kraayenbrink says. "We feel it needs to be faster than that."

Manure spreading has evolved in a different way in Europe, Kraayenbrink explains. Holland, for example, requires that manure be injected into the ground to reduce ammonia output. Spreader operators must stop at the edge of the field for a couple of minutes while the folded injectors are deployed. That gives enough time for tractor operators to deflate the tires. The technology hasn't been pushed to deflate tires faster.

But most Ontario manure tankers use splash plate technology to spread liquid manure and start spreading without a pause at the field's edge.

"In North America, there isn't a lot of work being done on compaction from a scientific point of view," Kraayenbrink says. There is more work being done in Europe.
PTG Reifendruckregelsystem GmbH, based in Neuss, Germany, uses on-the-go technology to inflate and deflate tires on equipment for a number of tanker manufacturers. PTG told Kraayenbrink and Bradshaw that 40 per cent of manure tankers in Europe are sold with their technology installed.

Kraayenbrink explains that European central tire inflation systems can be configured as either internal, with the air hose drilled through the axle, or external. A compressor is mounted on either the tanker or the tractor pulling it. A box on the tractor controls the pressure.

Kraayenbrink thinks this technology will be attractive to both farmers and custom operators. Farmers want better yields from uncompacted soils. Custom operators are likely to be intrigued by promises of better fuel economy and longer lasting tires. Both will like a wider spreading window.

Four times as expensive
Kraayenbrink watched a video in Europe of a tractor pulling a manure tanker into a wet spot in a field and bogging down. He says tires on the tractor and tanker were deflated and the machines continued on through the mud hole as if nothing had happened. If that can be replicated here in Canada, it will turn farmers "into believers," he says.

Manure tankers in Europe cost four times as much as in Ontario, but that's not just because of the inflation systems, says Kraayenbrink. He points to steering systems on tankers, suspension and special pumps as well as certification necessary for the axles in some countries. All of them are more expensive.

Kraayenbrink remembers when he put radial tires on farm equipment.

"We noticed the difference right away." A tractor with radial tires can pull a bigger plow than a tractor with bias tires, for example. "These are expensive tires but you can pencil it. It costs you a lot of money when you damage your soil."

Stewart says a deal is being negotiated with tanker manufacturer Nuhn Industries in Sebringville to build and test a prototype in Ontario. An inflation-deflation system hasn't been chosen yet. Three years of testing yields are likely to be required to sell producers and manure custom operators on the benefit of these systems.

Bradshaw and Kraayenbrink took note of some other European technology that also reduces compaction. One such innovation is a ball hitch and hydraulic cylinder that shifts weight via the top link on the three-point hitch to the front axle on the tractor. Bradshaw thinks this might eliminate the need some farmers have for salt and water ballast in their tractor tires.

"We want farmers to think outside the box," Kraayenbrink says. "We seem to be into a time of weather extremes, and the planting and manure spreading window is smaller. That's where this type of technology can make the difference between getting the job done or not."

Kraayenbrink raises purebred pigs from 800 sows at his home farm and a separate operation at Mildmay. Last year, his corn yield plots, planted on Apr. 24 and on May 4, averaged just over 161 bushels per acre, a range of 140 bushels to 183, depending upon the hybrids grown. His growing area north of Drayton draws 2,600-2,650 corn heat units. University of Guelph researchers have used his farm for compaction studies for several years.

"Some people would say we are fanatical" about compaction, he says. "The plant at the end of the day will tell you what you did to the soil."

Anne Verhallen is a Ridgetown-based soil management specialist for horticulture with OMAFRA. She says soil structure is a major issue for many horticultural growers. She recently surveyed tomato growers who were identified by processors as top producers. She says they consistently mentioned compaction and soil quality. "They all had crop rotations that were at least four years long. Most used no-till in every crop except for tomatoes and they built their soil in cover crops."

Dennis Nuhn, owner of Nuhn Industries, predicts that inflation-deflation technology will be even more beneficial to farmers on clay soils in Ontario than it is on farms in Europe.
He says it may be five or 10 years before this technology is viable and widely adopted.

Low livestock prices will hold back its use, but he expects that farm returns will increase soon and farmers will again be able to invest in order to get even more out of their efforts. There may also be more demand for this technology because weather seems to be headed into a wet cycle, which he saw 30 years ago when he began in the manure spreading business. BF

Sidebars


Brothers ‘made a religion of reducing soil compaction'

Compaction reduction pioneer Bob Misener says manure spreaders are one of the worst offenders when it comes to equipment causing compaction on farm fields. "You are putting on fertility and beating the s**t out of the soil to do it."

Misener mostly retired from farming last year when he and his brother sold Misener Farms Ltd. near Caledonia in Haldimand County, but he keeps his hand in farming 100 acres near Acton. The brothers were honoured in February for their work by the Innovative Farmers Association of Ontario. Ken Nixon of Ilderton, the association's current president, says Bob and his brother Tom "made a religion of reducing soil compaction."

The flagship of their achievement was a grain cart, called Lightfoot, built in co-operation with Innovative Farmers. Grain buggies haul grain from the field to trucks or wagons parked on the headlands while the combine continues to harvest. Grain buggies increase harvest productivity dramatically, but can damage fields if heavily laden.

The Miseners modified the sub-frame and walking beams of the buggy "to accommodate a big honking set of radial tires." Since then, grain cart companies have started offering either a large tire option or rubber track option. They didn't before the Miseners "pushed the envelope," Nixon asserts.

With its original 14-2-tires, the fully-loaded, 650-bushel-capacity buggy was exerting 94 pounds per square inch under its wheels. "If you want to reduce yield, do that," Bob Misener says.

Equipped with tires that cost $6,000 each, the buggy put less pressure on the soil than did the combine.

Machinery isn't the only, or even the first, answer to reducing soil degradation by compaction, says Bob Misener. More important than equipment may be tile and crop rotation. "To me, permanent improvements are more important than something that has to be replaced," Misener says.

Tiling increases the number of days when a field is fit to bear the weight of machinery.

Still, "you need the equipment for the days when (the soil) isn't fit," he says
"Soil health, productivity, sustainability, is a very neglected issue over all," adds Misener, quoting now-retired Ridgetown soil researcher Charlie Baldwin as saying "the more you pay for land, the worse you use it."

The evolution of farming has meant more horsepower, less labour and bigger machinery. "Tires are the easiest thing to sacrifice" to make a deal on a tractor or a combine, Misener says, but that deal may be costly in the end. "If your soil is important, you've got to spend the extra $5,000 or $10,000 to make (the machine) compatible with your goals agronomically."

Misener also equipped a fertilizer spreader so that tires put no more than eight pounds pressure per square inch, critical when spreading in the fall or spring. However, inter-row crop sprayers are still a challenge, he says. Tires on sprayers can't be more than 25 inches wide because crops are planted in 30-inch rows. He says he doesn't know how to solve that.

OMAFRA's Hayes says a lot of progress has been made but there is still work to be done.

One of the biggest issues is the loss of organic matter in recent years. It's important to soil health and soil structure, nutrient cycling, aggregate stability and water holding capacity. Organic matter also acts like a spring in helping soil to spring back from compaction. There was a lot of soil erosion in the winter of 2008-2009, Hayes says.
"Government stimulus (for agriculture) should be aimed at soil health and productivity," Bob Misener says. "Lack of suitable rotation is probably one of the biggest problems in agriculture today." BF

Soil compaction – a problem that ‘flies under the radar'

Twenty years ago, the farming community considered compaction the number two degradation problem in Ontario, says University of Guelph soil scientist Ray Riley.
A September 1986 report by the Science Council of Canada, "A Growing Concern, Soil Degradation in Canada," pegged the losses caused by soil compaction at $21 million in 1985 dollars in Ontario and $100 million in Quebec. (In Ontario, erosion was estimated to cost $58 million, and only $10 million in Quebec.)

The report followed on the heels of a 1984 study called "Soil At Risk," published by the House of Commons Senate Standing Committee on Agriculture.

Riley doesn't think compaction risks have decreased. He hasn't seen any newer estimates of the cost of soil degradation either. Farm equipment has gotten bigger, although technology has mitigated some of the effects.

He expects that innovations in crop residue management have reduced erosion losses since 1985. He also thinks that soil compaction flies under the radar these days.

Recently, he applied to the OMAFRA-University of Guelph Partnership for money for a research project on soil compaction. "They turned it down. One of the reviewers questioned whether soil compaction is a problem in Ontario."

Someone in OMAFRA doesn't think compaction is an issue any more, Riley says. "That's not true. Soil compaction is an insidious thing. Soil erosion is very obvious." BF