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No-Till Vegetables Gain Ground Growers throughout the country find benefits in no-till production.

By Marni Katz

No-till crop production may not be sweeping the nation in vegetables as it has in corn and soybeans, but from the eastern seaboard through the midwest and into the far west, vegetable growers increasingly are looking into the potential cost savings and conservation benefits of a no-till system.

“If you compare the acreage to soybeans and corn there isn’t much acreage in no-till vegetables,” says horticulturist Ron Morse, an innovator in no-till vegetable production at Virginia Tech University. “But if you compare it to the past, there is significant movement.”

Equipment innovations and trial-and-error during the last decade have helped growers develop no-till production systems on everything from cole crops and crucifers to tomatoes that can help conserve soil and water, increase yields and save on cultivation costs and inputs.

Perhaps one of the greatest success stories in no-till vegetables is in pumpkins. For pumpkin production in states such as Virginia, Maryland, Delaware and Pennsylvania, no-till systems are now more the norm than the exception, Morse says.

“The reason it’s taken off so fast is the improved quality,” he says. “Pumpkins that lay on a matt of straw instead of the soil are naturally going to look the best.”

But other crops also are being transitioned to no-till in limited acreage across the country. Vegetable grower Steve Groff over the last 20 years has developed a permanent cover cropping system that has helped him eliminate tillage on 175 acres of pumpkins, tomatoes, sweet corn and other vegetable crops on his Cedar Meadow Farm in Holtwood, Penn. The no-till system has not only reduced cultivation costs and improved yields and quality, but has also helped Groff manage the soil erosion associated with the farm’s sloping topography.

“You could not pay me to till my land anymore,” Groff says. “Soil erosion has gone from 15 tons per acre, per year, to almost nothing. Organic matter [in the soil] has gone from 2.7 percent 15 years ago to 4.8 percent this year, and yields have improved 10 percent.”

Groff direct seeds or transplants into a hairy vetch and rye cover crop mix that is seeded in fall at a rate of 20 to 25 pounds per acre of vetch and 30 pounds per acre of rye seed. He also plants crimson clover at 10 pounds per acre. As a cover crop preceding sweet corn he prefers hairy vetch seeded at 25 pounds per acre with 1 bushel of oats. After the first week of October, Groff limits cover crop plantings to rye seed at 2 bushels per acre.

These killed cover crops will contribute a significant amount of nitrogen into the soil which can help reduce the costs of applied nitrogen. According to Sieg Snapp, associate professor of horticulture at Michigan State University, typical rye/vetch mixtures will contain about 2,000 pounds per acre of dry matter for the first six inches of growth. Young legume covers, such as hairy vetch, are about 4 percent nitrogen, so incorporating a 6-inch hairy vetch cover will add about 80 pounds N per acre, she says.

About 60 percent of that actual nitrogen will be available to the subsequent vegetable crop, although nitrogen benefits will build over time with a no-till system, Snapp says. Allowing the cover crop to grow an additional 6 inches will increase the nitrogen contribution by more than 40 percent and incorporating the residue will shorten the time before that N becomes available.

At Cedar Meadow Farm, Pumpkins and sweet corn are direct seeded with a custom built direct seed planter into the cover crop, which is typically killed with Roundup and rolled down with a rolling stalk chopper prior to planting. The planter is built on a Kinze frame with Monosem row units. The implement also has Yetter parallel linkage and Rawson coulters, Martin spading closing wheels and a foam marking system. For his transplant crops, such as tomatoes, peppers and broccoli, Groff uses a customized RJ Equipment transplanter.

The advent of customized equipment has been a significant boon to no-till vegetable production, according to Morse. Morse himself developed a subsurface tiller that slices residue, loosens the soil, deposits fertilizers and can even install drip tube in a single pass. The commercially available implement paves the way for a normal transplanter to follow behind that has been modified for no-till with a double disk coulter attached to the shoe so it can travel through the residue without building up trash. The modified equipment runs about $7,000 for a one-row subsurface tiller and about $12,000 for the two-row implement.

In some cases, Morse says, growers will strip till their field, cultivating a narrow strip between 4 to 14 inches into a winter mulch, to accommodate a conventional transplanter. That provides considerable cost savings over modified equipment, but also reduces some of the benefits of conservation tillage.

“To retain the benefits, make the strip as narrow as you can get by with,” Morse advises.

In addition to changing the way land is cultivated and fertilized, no-till will often alter pest complexes in the field, which must be managed differently than conventional vegetable fields.

“It’s pest specific in terms of what the mulch does to insect and disease problems, whether they are better, worse or the same. Colorado potato beetle, for instance, doesn’t like mulch so growers get good control, but slugs love a moist environment. It just depends on the pest,” Morse says. “Lots of cover crops can deter growth of nematodes, so we’re looking at it as a potential replacement for methyl bromide.”

Groff says pest complexes change significantly with the presence of vegetation and increased soil moisture. For instance, he says, there is less incidence of soil borne diseases, such as early blight, and less Colorado potato beetle pressure on his crops, while airborne diseases, such as powdery mildew, and pests such as aphids have stayed the same and stink bug and slug pressures have increased.

It’s important, Groff says, for growers to be prepared for these differences going into a no-till system. Despite the learning curve, he adds, for the grower who does his homework, the no-till system offers significant advantages. No-till growers typically save money by reducing water use in irrigated systems, reducing cultivation equipment and fuel costs and minimizing inputs, such as herbicides and fertilizers.

In addition, Morse says, growers often realize increased yields through soil moisture conservation and enhanced quality, particularly for crops that lay on the ground. At the same time, there are increased costs in equipment and seed for managing the cover crop.

“A grower has to be really careful to understand the system and do it right,” Morse notes. “It works if you do it right, and there are a lot of advantages.”