TALKING SHOP:
Carolina Farm Stewardship Association Conf., Nov. 7-9, Rock Hill, SC

By Chris Bickers

ROCK HILL, S.C. --Your crop rotation and cover crops can do a lot for you -- and you had better be sure they do it!

That was the messageto organic farmers who traveled to Rock Hill SC in early November to attend the annual Sustainable Agriculture Conference sponsored by the Carolina Farm Stewardship Association (CFSA).

The group’s 18th annual conference had a cluster of workshops on aspects of managing selected crops to improve soil fertility, increase water retention, enhance soil organic matter, manage disease and insects and keep down weeds for no-till transplanting.

Sponsor Profile Carolina Farm Stewardship Association (CFSA) Purpose: CFSA is a membership organization of more than 800 farmers, processors, gardeners, businesses and individuals in North and South Carolina who are committed to sustainable agriculture and the development of locally-based, organic food systems. Founded: In 1979 by a group of farmers, gardeners and consumers to support each other in their efforts to foster the growth and distribution of organic food in the Carolinas. Mail: PO Box 448, Pittsboro, NC 27312 13 Hillsborough Street Suites 3 & 8, Pittsboro, NC 27312 Contact info: Tony Kleese www.carolinafarmstewards.org (site under re-construction, click “Farmer Resources”) cfsa@carolinafarmstewards.org (919) 542-2402

What is crop rotation? Jim Riddle, an organic certification expert from Minnesota, defined it for a workshop at the conference as the practice of alternating the crops grown on a specific field in a planned pattern or sequence in successive crop years so that crops of the same species, or family, are separated year-by-year by other crops in a beneficial way.

One basic rotation might be to plant a rye cover crop right after corn in a corn/soybean rotation. The rye will scavenge residual nitrogen and provide ground cover in the fall and over winter. When it is killed in early spring, the rye provides a water-conserving mulch and suppresses early-season weeds for the following soybean crop.

A subsequent cover-cropping step could be planting hairy vetch (a winter annual legume) behind the soybeans to provide nitrogen for corn the following spring. (For more on the basics of rotation, see “Overview of cover crops and green manures” in the “Fundamentals of Sustainable Agriculture” series at http://attra.ncat.org/attra-pub/PDF/covercrop.pdf)

An optimal crop rotation for organic grain production, said Riddle, would:
–Maintain or improve the organic matter level of the soil.
–Provide for pest management.
–Make it possible to manage deficient or excess plant nutrients.
–Improve erosion control.

To make a crop rotation work, find the highest return for each cash crop included. Determine if a cover crop can be grown on contract or can be fed to your livestock. Find out if seed is available when you need it, and if can you meet any of the market’s quality demands.

You also want to look for special agronomic characteristics in rotation crops that are serving essentially as cover crops, i.e. have their primary value in benefiting the soil or the next crop, rather than to be harvested and sold. The ideal cover crop would germinate and emerge fast, compete effectively in the field with other plants and weeds, tolerate adverse climatic and soil conditions, suppress easily and be inexpensive to establish.

You are not likely to find a cover crop with all these characteristics, Riddle explained. You must set priorities, determine the top priorities for your cover crop and then choose an appropriate species. Be sure to find out which species do well in your region.

Selecting crops for insect control
Rotation and cover crops definitely have a role to play in insect control, said Debbie Roos, an agricultural extension agent from Chatham County NC who spoke on organic insect management.

As insects overwinter in soil and debris, they will re-infest the new crop if it is susceptible. Pest populations can build up. The solution is to rotate with non-susceptible crops so that pests have no food or shelter. Leave as much time as possible between related crops to make conditions difficult for the pests.

Crop rotation is not effective for controlling pests with a broad host range. There are three questions to ask yourself, Roos said:
-- How long can the pest persist in the field without any host?
-- Can it invade from other areas?
--Does it survive well on other hosts when your crop is not present?

The more holistic but less precise approach is to use good bugs to fight the pest varieties. Here, cover crops can provide a valuable habitat and food source for beneficials, allowing their populations to build up early in the season before the emergence of pests. Using companion plants in a sustainable program has been suggested as a pest control strategy. This approach could involve attractant (trap) crops like caraway, fennel and hyssop. There are thought to be some repellent crops: catnip and tansy are said by some to repel aphids, while artemisia is said to repel flea beetles. For Roos, the value of all this remains rather vague. In some situations, alleged companion plants have been shown to actually increase pest populations.

"There are lots of recommendations about companion crops out there with little scientific evidence on a field scale," said Roos. "We need more study before recommending." Growing a diverse mixture of crops, in alternate rows across a field, helps attract beneficials and impede pests. Roos is conducting on-farm research to learn more about how farmers may benefit from beneficial insect habitat.

When your cover crop becomes a weed
Any cover crop species will work better with some crops than with others. Kenny Haines of Looking Back Farms in Tyner NC had good success with a rye/hairy vetch cover crop back when he was growing mainly fruits and vegetables. But then he started planting grains, and the hardseeded vetch presented a problem.

“It’s cheap and grows vigorously, but it can easily go to seed and come up in your wheat,” said Haines. “For that reason, we have had to get away from vetch.” Much of his land is in a rotation of corn followed by wheat and soybeans, though rye/vetch still has an occasional use if Haines can place it well before wheat. He also grows watermelons occasionally in this rotation.

Haines likes to till as little as he can, but because of a problem with the cover crop, he is reluctant to go 100 percent no till. “If you no-till soybeans into wheat straw, you have no defense if weeds come up,” he said. “If I plow [on the other hand], I have a range of cultivators to choose from to do the job.”

New varieties make small grains a better tool
If you need a small-grain crop in a rotation, either as a cover crop or cash crop, the most important step is to choose the right grain and the most suitable variety. There are varieties of all the Southeast’s major feed grains -- wheat, oats, barley, triticale and rye – that will all do well in sustainable agriculture, said Paul Murphy, an NC State University plant breeder.

That is in part because breeding programs have followed priorities that are as important to organic agriculture as they are to conventional farming. “Traditionally in this area, all the grains have been considered low-input crops,” said Murphy. “Farmers anticipate resistance to all the important pests in the varieties that are available, since they don’t want to have to treat for them.” That means there are plenty of varieties for the organic/sustainable farmer to choose from.

“Good yield and quality should be factors in a variety choice,” said Murphy. “But also take into consideration resistance to powdery mildew, Hessian fly and leaf rust. If you select carefully among the numerous varieties available, you will be able to get that resistance with the other characteristics that you need."

Wheat: Among wheat varieties, a new introduction called “NC Neuse” (after the Neuse River) could prove to be a good choice in organic programs, said Murphy. It is resistant to powdery mildew and leaf rust and is also moderately resistant to fusarium head blight and Hessian fly.

There may well be a benefit to choosing a hard red winter wheat variety rather than a soft red winter wheat, the type traditionally grown in the south, said Murphy. Research at NC State on identification of suitable hard wheats is progressing rapidly, and recommendations will be available for planting in fall 2004.

Barley: A trend in small-grain breeding that could provide some tools for sustainable agriculture growers is the recently developed breeding goal of “hull-less” seedheads. One such variety, a barley called “Doyce,” should be available in 2004 from Virginia Tech. It grows and looks like regular barley until it is mature. During combining, the hulls separate from the grain. It has attracted some interest as a high-energy animal feed and also as feedstock for ethanol production.

Oats: Thishe new characteristic has not been confined to barley. A new hull-less variety of oat called “NC Hulless” is also available. Its hulls are threshed off the seed so you end up with a higher energy, higher protein feed. “This oat has a role to play in hog, poultry and perhaps even fish farming,” said Murphy. It could find a place in horse-feeding programs, as well.

Triticale: This grain -- a cross between wheat and rye -- has inherent insect and disease resistance that might make it a good fit in sustainable agriculture. “We have observed in our breeding nurseries that triticale has high levels of disease- and insect resistance and drought tolerance,” said Murphy. “Its grain has a high-quality protein that makes it suitable for hog and poultry feed, and many cultivars produce abundant leafy growth in late winter and early spring with potential for grazing or silage production.

“It performs well in the southeast and is relatively easy to produce. It has a niche, but as with hull-less barley and oats, make sure you have a market for it before you grow it,” he cautioned. N.C. State University released its first triticale cultivar, “Arcia,” in 2001.

Rye: Rye is popular as a cover crop because it has the highest level of allelopathy – weed suppression – of any of the common small grains.

“There is a danger, however, if you are planting a small-seeded crop like lettuce behind rye,” said Murphy. “Rye interferes with weed-seed germination, and so it might interfere with a small- seeded crop. Transplants would face less of a risk.”

Chris Bickers is a freelance writer-photographer in Raleigh, NC.