Creating Sustainable Farming Systems:
Rotations Build Soil, Control Pests, and Keep Farming Interesting

Cris Carusi and Martin Kleinschmit

Tom Larson grins as he shows off the Dragonfly, a sleek two passenger plane which he built over the course of several winters. Aviation is his hobby. His knack for craftsmanship shows as he explains how he built his plane from foam, fiberglass, and a Subaru engine. The Dragonfly embodies Tom's conviction that there is more to life than farming.

Tom approaches farming with a similar attitude of craftsmanship. He rotates soybeans, corn, oats with turnips and cattle through his ridge-till strip-cropping system. He adapted most of his own ridge-till equipment from used machinery. His irrigated 160 acre St. Edward farm, which includes 60 acres of row crops and 90 acres of pasture and hay ground, has been in his family for 61 years.

His grandfather and father raised monoculture corn on the farm until the early 1970s. At that time, a neighbor was experimenting with a corn-soybean rotation, and achieving good results. Tom liked what the beans did for the soil, and he saw income potential in the soybean crop. He and his dad decided to give rotations a try. The corn-bean rotation provided the Larsons with good returns and soil benefits. They eventually added oats to the system, to gain diversity.

Tom now rotates his crops in 152-inch wide strips (4x38"). Soybeans, the first crop in this rotation, provide a number of benefits to the system, including pest control, nitrogen for the following year's corn crop, and cash.

Rotations prevent insect pest populations from exploding. "Insects are creatures of opportunity," Tom explains. "They will build up in large populations where the environment is right for them. If you keep changing environments on them through rotations, it has been my experience that they do not become a large problem. Anyone who puts in corn after soybeans really should question whether or not they need a soil insecticide."

Corn is the second crop in the rotation. Tom chose to keep corn in the system because of convenience and tradition: "I wanted to raise corn, because that's part of your identity in this area. We're corn growers, and there's a convenient market for it."

Tom has seen increased corn yields from his system. With strips four rows wide, the entire corn strip benefits from the "edge effect". Under a conventional cropping pattern, yields in the middle of the field can be lower than around the edges, because of excessive heat buildup and health problems. Tom believes that his four row strips are an optimal size.

The third crop rotated into the system, oats, is planted directly into the corn stubble the following spring. The oats are harvested for grain or straw, depending on the market. Following oat harvest, Tom re-builds his ridges and broadcasts turnips, to provide fall forage for his cattle.

Crop rotations help control weeds, as tillage operations happen at different times for the various crops. Including oats in the system is particularly valuable, because the mid-summer harvest helps break weed cycles. Tom has had some trouble with early weeds, like shepherd's purse, but controls them with shredding. He believes that weed control is the best argument in favor of ridge-till planting and cultivation.

The oats have improved soil tilth, as their root system builds soil structure. It took about three years for him to observe improvements in his soil, like an exploding earthworm population.

Once he had successfully interrupted weed and insect cycles and improved his soil, Tom's next concern was to provide winter feed for his cattle. He has 60 head of cattle to feed through the winter. Beginning in the fall, when the pastures are dormant, he supports his cattle herd by strip grazing the corn and bean residue, and turnips.

The turnips are the most profitable part of his operation, as he can potentially graze 300 head of cattle per acre per day on this crop. Tom figures that he gets 4-5 times more net income per acre from his turnips than from corn. His input costs for the turnips are minimal, and he has no harvesting expenses. The animals do the work for him.

In his lifetime, Tom has moved from a conventional corn monoculture to this diversified system. He quit applying herbicides 6 years ago, and insecticides 10 years ago. He switched from anhydrous to manure fertilizer last year. He is in the process of certifying his fields organic. In the future, he would like to provide extra nitrogen by interseeding a legume into his corn crop.

Tom's system provides him with many quality-of-life benefits as well. Although the system is more labor-intensive than conventional farming, the work is spread out rather than bunched into stressful "crunch periods". Better scheduling leaves him more free time in the day for other things, like his plane. He has noticed more wildlife on his place, which he appreciates.

His wife, Deb, works in town to support the farm, as many farm women do these days. Tom's efforts pay taxes and insurance, and his wife's income keeps food on the table. Good quality of life is more important to the Larsons than making a lot of money. Says Tom, "I'm willing to accept a lower standard of living for an improved quality of life."

Much of Tom's inspiration comes from Chinese and Japanese farming systems. He cites Farmers of Forty Centuries by HF King and One-Straw Revolution by Mansanobu Fukuoka as favorite titles. He is impressed by how these cultures use and re-use their own resources as much as possible.

"Basically, do only what's necessary," advises Tom. "Always look at what you're doing and ask yourself, 'Why am I disking? Why am I planting and harvesting in this manner?' Constantly ask the question, 'Is this absolutely necessary, and is there an easier, cheaper way of doing it?'"

Tom prefers to farm from the neck up, substituting management strategies for labor whenever possible. "I think that we've given away our ability to know our weeds and our soils. Its gotten to the point where people don't farm fields anymore. They farm farms."

"There's other things that I could do that would be more financially rewarding," he adds. "I guess I enjoy the challenge, or I wouldn't do it."