Bunker covers, plastic-wrapped bales and bagged silage have improved the quality of life for dairy producers and the herds they feed. But once those feeds are out of the bag, so to speak, farmers are left holding it.
Usually, silage bags and bunker plastic are burned or hauled to local landfills. The Wisconsin Department of Natural Resources and some forage experts, however, hope growers will soon take a different approach: recycling.
“Our Department of Natural Resources is concerned about all the open burning that is going on throughout the state,” says Brian Holmes, a University of Wisconsin ag engineer.
“A lot of agricultural plastics are being burned. The big concern is the release of dioxin, which is a very toxic compound produced when burning lots of different materials at relatively low temperatures.”
By recycling film plastics used for ensiling, Holmes sees a solution to the problems of burning, which in some states, like Wisconsin, is illegal, and overloading landfills.
A few major hurdles need to be cleared before film plastics can be effectively recycled, says Roger Springman, program coordinator for the Wisconsin Department of Agriculture, Trade and Consumer Protection and the state's Agriculture Clean Sweep Program.
One is dirty plastic. Once a dairyman rips open a bale or silage bag, that plastic is stripped away and thrown in a pile. Sometimes it goes into a dumpster to be hauled to a landfill. Yet that plastic probably has hay or corn silage, dirt or manure clinging to it. Recyclers aren't prepared for plastics in this condition.
Another is making recycling easy enough for farmers to be willing to do it.
A third hurdle: Having the used plastic in a form and big-enough quantities to make it worthwhile for farmers and recyclers to handle.
Springman says recyclers are working on ways to make use of film plastics by recycling them into sturdier plastics for decks, porches, signs, etc. One Canadian company has been working on a machine to clean plastic and another company in Utah is developing a new processing system to handle dirty plastics, he adds.
Holmes, at the University of Wisconsin-Madison, has just started to develop an on-farm cleaning device. “I envision a machine that could be used on farms that would make this stuff cleaner and more dense for transport,” he says.
Such a machine could make recycling easier for farmers, Holmes thinks.
“We're trying to make it a low-cost machine with the idea that producers don't have a whole lot of incentive to do this yet.”
Recyclers and growers will have to work together to devise a system that will centralize the plastics — so neither has to incur a high transportation cost, Springman says.
In Europe, he adds, producers use skid-steer loaders to crush and compact plastics in a type of basket. Then the recycler comes to the farm, removes the filled basket and replaces it with an empty one.
“You can't expect a farmer to do more than collect the loose stuff, throw it into a container and compress it until the container gets full,” Springman says.
A recycling organization called Ag Container Recycling Council is looking into another option: compressing and baling the plastic. “The technology is already here,” says Spring-man. Called tiger balers, these machines are used by companies to compact their waste.
It's hard to get a number on how much film plastic is used on the average dairy and how much plastic is available for recycling. Around 90% of the film plastics used in agriculture go to landfills, Springman thinks.
He and a local extension agent examined use in Dane County, WI, which boasts not only of Madison but also of its dairy production. “We estimated there are 48,000 cows in the county and 300 herds on DHIA, averaging 160 cows/herd.” He then added up the amount of film plastics used as bunker covers and silage bags on one particular farm. Estimating on a per-cow basis, Springman figures about 568,000 lbs of film plastic are being used by farmers just in that one county.
“A local distributor of film plastics said he would expect a modern dairy farm to use 1,500-3,000 lbs of plastic per year,” Springman says.