Home - Weed Warfare – Summer 2010
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.
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.