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Columns::September 16, 2002
Parting thoughts: Provost reflects on successes, challenges of her tenure at UGA
The forest and the trees
Southern forest products industry loses $430 million
Fiber artist’s exhibition challenges stereotypes about ‘women’s work’
Helping hands
University Council will consider domestic partners policy at first meeting
Campus Closeup
Two curators, deputy director join Georgia Museum of Art
Newsmakers
Good vibrations
Campus News
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| Sandy Cederbaum weighs nestlings as part of a study of the effect of farming practices on songbirds. |
Sound science
Research shows clover strip-cropping in cotton provides critical habitat for threatened songbirds
By Helen Fosgate
hfosgate@smokey.forestry.uga.edu
Cotton farming is on the rise across the South, and that spells trouble for rural songbirds. Conventionally grown cotton relies heavily on pesticides, herbicides and plowing or disking every three weeks, contributing to the steady decline of birds like the Eastern meadowlark, bobwhite quail and grasshopper sparrow.
But research by wildlife scientists in UGA’s Warnell School of Forest Resources shows that alternative farming
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| From front: John Carroll, Sandy Cederbaum and Bob Cooper worked together on the project. (Photo by Peter Frey) |
practices like clover strip-cropping provide critically important habitats for threatened songbirds. Interplanted in rows between the cotton, clover offers the birds ready cover from predators, insects for food and, just as importantly, enough time to nest and fledge their young between field operations. This is the first study to compare the effects on birds of conventional and alternative farming practices in cotton.
“Other studies have looked at alternative farming systems in terms of cost savings, erosion control and soil fertility,” says UGA wildlife researcher Bob Cooper, “but we’re the first to look at clover strip-cropping and conservation tillage systems in cotton with regard to wildlife.”
Much of the decline in songbird populations is linked to the loss of rural land, here and in South America, where many birds migrate for winter. Thousands of rural acres have been converted to apartment complexes, shopping areas, suburban housing--even to pine plantations. In South America, forests are being bulldozed to make way for non-sustainable forms of agriculture such as cattle farms and sun-grown coffee. None of these habitats provide the diverse combination of natural woodlands, open grasslands and shrubby areas the birds need to feed and raise their young.
The researchers involved in this study included Cooper, UGA wildlife biologist John Carroll and graduate student Sandy Cederbaum. They conducted the study with the cooperation of several farmers in east-central Georgia who are concerned about songbirds.
Their research was presented at last year’s meeting of the American Ornithologists’ Union.
The researchers compared the density of birds and vegetative cover in cotton fields grown with different approaches--using conservation tillage, using clover strip-cropping or using intensive farming practices. They monitored the fields through winter, spring migration and finally through the breeding and summer growing season, recording the type and number of bird species in each farming scenario. To learn more about food availability for the birds, they also sampled the insects in each field type, noting whether they were beneficial or crop pests.
“Our idea wasn’t to try to come up with something new but to look at existing cropping systems from a wildlife standpoint,” says Cederbaum, who monitored the fields through the seasons. “We were really surprised by the extent to which the birds responded to the clover fields. Before this, I hadn’t appreciated the extent to which agriculture could provide beneficial habitat for birds.”
Preparation for strip cropping begins in the fall when farmers plant a cover crop of clover to stabilize the soil and allow beneficial insects to build up before planting the cotton crop in early May. To prepare the land for cotton, farmers use a hooded sprayer to kill 20-inch strips of clover with a herbicide and later plant cotton into the brown strip. This leaves a 20-inch strip of living clover between each row of cotton. As the season progresses, the clover dies back naturally, but still provides enough structure and cover to sustain beneficial insects, some of which move into the cotton plants where they help control pest insects. Alton Walker, an independent crop consultant in Wrens, has been fine-tuning this technique for years.
The UGA researchers found that birds flocked to the strip-clover fields, feeding on plentiful insects amid the blooming clover. The conservation tillage fields also provided some cover and insects, though not nearly as much as fields with the living clover. The brown, barren landscape beneath the conventional cotton crop supported very few insects and offered no cover.
“Many people fail to realize that cotton fields are wildlife habitat,” says Carroll. “The key now is understanding how we can integrate the needs of wildlife into existing crop-production systems.”
Other studies have shown that clover strip-cropping also is profitable, since growers cultivate less and use fewer pesticides, herbicides and fertilizers. Sharad Phatak, horticulture professor at the Coastal Plain Experiment Station in Tifton, who has been studying alternative cropping systems for more than 30 years, was encouraged by this study.
“I was very impressed with the number of birds in the clover stripped fields,” he says. “I believe that by changing cotton farming in this direction, we can support and help songbirds as well as build and protect our soil.”
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