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Agriculture & Foods - Weed Warfare

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Eric Gallandt

In the epic struggle, Eric Gallandt is the smal-scale growers' staunchest ally.

When fictional poltergeists and phantoms descended on Manhattan, New Yorkers called Ghostbusters.

When hairy galinsoga, ragweed and redroot pigweed — which are very real and equally scary, by the way — descend on Maine, farmers call weed busters. Specifically, they call Eric Gallandt and his team of researchers at the University of Maine.

For small-scale organic farmers, weeds can be as haunting and confounding as shape-shifters. They compete with crops for water, nutrients and, if they grow more quickly than the desired plants, light. This can cause the quality of a crop to suffer, and in some cases can reduce or even eliminate yield, which cuts into growers’ profits. Left to their own devices, weeds can quickly proliferate.

Organic standards forbid the use of synthetic herbicides, which are inexpensive and highly effective. The alternative is cultivation — weeding with tractor implements, a hoe or by hand between rows — but that’s costly, time-consuming and kills far fewer weeds.

redroot pigweed

Redroot Pigweed; Illustration by Carrie Graham

Gallandt, a UMaine associate professor of weed ecology and management, has made it his mission to help small-scale growers who plant diversified crops. He takes a systemic approach to weed management by focusing on the ways in which growers address the seed bank — the seeds at the soil surface and the seeds incorporated in the soil.

As any gardener knows, weeds grow like, well, weeds. They’ll do whatever it takes to ensure their survival, and a lot of this depends on the seed bank. Some weeds have seeds that remain dormant for a period. Others rely on animals to spread their seeds and still more develop seeds that can remain viable in the soil for decades.

In the past, Gallandt has researched microbial decay of seeds in the soil, looking for conditions that may accelerate seed loss, but without much success. He’s currently working with small farmers to find ways to manipulate the environment so that there are fewer weed seeds in the soil to begin with.

“How do we get the number of weeds killed during cultivation higher?” Gallandt asks. “How can we get it closer to that of an herbicide? And if we can’t, how can we make the tools more effective? If we have to use them twice, can we make it even more efficient?”

According to U.S. Department of Agriculture census data, more than 300,000 new farms began operating nationwide between 2002 and 2007. The trend among these farms is that they tend to have diverse crops, fewer acres, lower sales and younger operators who also work off-farm. In fact, the majority of U.S. farms are smaller operations.

More than 36 percent are classified as residential/lifestyle farms, with sales of less than $250,000 and operators with a primary occupation other than farming. Another 21 percent are retirement farms, which have sales of less than $250,000 and operators who reported they are retired.

The sector may be growing, but weed management technology hasn’t kept up. Until recently, the options for small-scale farmers have been hand tools. Tractors are engineered for larger, less diversified plots of land.

“If you look at smaller organic farms, they’re basically using hoes,” Gallandt says. “They’re very nice hoes. They’re precision hoes. But they’re hoes. The technology hasn’t changed much since the 1800s.”

Until recently, that is.


Common Lambsquarters; Illustration by Carrie Graham

Gallandt and his team spent last summer researching the effectiveness of the Weed Master, an innovative Finnish machine that’s best described as a small, human-powered tractor. During a sabbatical in Copenhagen several years ago, Gallandt met European colleagues who work on weed management in organic systems. One of them introduced him to the Weed Master.

The device combines the best aspects of hand tools — lightweight, small, portable — with the versatility and add-ons of a tractor. Gallandt wanted to know if a machine like this would benefit Maine farmers, and he received a grant from the Maine Agriculture Center to import a Weed Master and tools such as a flame weeder.

During the 2009 growing season, he worked with three Maine organic farms — Peacemeal Farm in Dixmont, run by UMaine alumnus Mark Guzzi; Fisher Farm in Winterport, run by Rose, Joe and Dennis Fisher and UMaine alumna Beth Haines; and Fail Better Farm in Montville, run by Clayton Carter. Students at UMaine’s Black Bear Food Guild ran a concurrent experiment comparing the efficiency of weeding by hand or with a short- or long-handled hoe, a wheel hoe and the Weed Master.

They found that overall, the Weed Master didn’t provide superior weed control, but it was exponentially faster than cultivating by hand or with any of the other tools. And in a small-scale operation, time is money.

“Farmers were pretty impressed with how fast it worked and how easy it was to adjust the tools to the unusual crops and planting patterns that they have,” Gallandt said. “It was very simple.”

Gallandt and his colleagues in New Hampshire and Vermont recently wrote a $2.4 million grant to purchase Weed Masters, along with specialty hand tools from Johnny’s Selected Seeds in Albion, Maine, for on-farm research in those states, as well.

“Farmers could really use some innovation on their farms,” Gallandt said. “We’d like to retool northern New England for small- to mid-scale diversified vegetable farming by getting farmers exposure to innovative tools.”

Hairy Galinsoga

Hairy Galinsoga; Illustration by Carrie Graham

The cost of importing the Weed Master may be prohibitive for many small-scale organic farmers — the whole setup runs a little less than $7,000. And in certain situations, hand-powered tools may be a better alternative anyway.

But innovation is more important now than it has ever been. The fact that the number of such farmers is growing points to a need for more effective products and methods. But so does the prospect of climate change. According to Gallandt, an overall rise or fall in temperature won’t make a huge difference, but variability in weather patterns will.

That’s because the window for ideal cultivation conditions is very small — and timing is everything. The weather needs to be moderately dry at the same time the weeds are at their smallest growth stage — called the “white thread” phase — early in the season. An evening rainstorm can take regular weed-killing rates — usually around 80 percent to 85 percent — down to 60 percent. That means more passes with a hoe, which means more time, which means more labor, which means money lost.

“Organic farmers are going to be in trouble,” Gallandt says. “Cultivation is really dependent on the environment and as the weather begins to get more unpredictable, you can see why we’re more interested in some of these tools with high efficiency rates.”

Weeds can tell us a lot about our environment, the weather and the farming practices we employ. Some, such as the edible wood sorrel or the attractive common purslane, are even fairly pleasant. But most of them are as pesky as the poltergeists in Ghostbusters and as hard to bring down as the Stay Puft Marshmallow Man.

Gallandt’s advice to farmers and gardeners? Persevere. And don’t be afraid. He and his team of weed busters will be around to help.

“Over time, as you start managing the seed bank, you start to solve some of your weed problems, but the things that you still see are the things that are slipping through in the unfriendly environment you’ve created. You end up with a new species that has a trait that allows it to thrive in the environment it’s in,” Gallandt says. “They’re basically doing their job, and to think that we’re going to solve this problem and make them go away completely goes against eons of evolutionary strategy.”

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