Increased yields, reduced nitrogen leaching and sharp cuts in diesel consumption: those are some of the benefits of cutting plowing out of the traditional agricultural cycle. Instead, let the grower’s best friend, the lowly earthworm, do the job beneath the soil’s surface. Gustaf Andersson, a farmer who runs Peterberg’s farm in the Swedish hamlet of Breda, is a pioneer in a movement that’s being called “plow-free cultivation.”

“This year it looks as if we won’t need to plow anything on our 300 hectares”, says Andersson. Together with his wife, Maria Berg, he has run the farm since taking over from his parents in 1980.

On traditional farms, after the harvest in September and October the fields are plowed to a depth of about 25 centimeters within a few days. This is done largely to bury the remaining straw on the surface, remove weeds and aerate the soil. It’s a time-consuming, energy-intensive process that’s been called Sweden’s largest excavation job.

In the early 1980s, Andersson began experimenting together with a few owners of neighboring farms who share the rigid and intractable Uppland clay. Andersson let three or four years pass between each plowing, and he began to realize that the soil became healthier when it wasn’t turned over as often.

“I began to skip plowing altogether, simply scraping the top seven to eight centimeters using a cultivator and a harrow with sharp, thin pins,” Andersson says.

Improving the method

The experiment continued with testing of crops that thrived without plowing. The first step involved those that leave little straw after harvesting, such as oilseeds and legumes. Next the farmers moved on to barley and oats, and finally to winter wheat.

In the 1980s, equipment manufacturers introduced sowing machinery that could handle fields covered in crop residues while depositing the seeds deeper in the soil. The Swedish farm equipment maker Väderstad is at the forefront of developments in processing equipment to facilitate plow-free growing. One major improvement is that, with certain crops, farmers can sow directly behind the combine without tilling the soil.

“We discovered quite quickly that there were more earthworms in the soil. Their burrowing makes the soil porous so the water moves freely. The worms are doing a better job than the plow,” says Andersson.

Environmental side-effects

When the project began, Andersson and his neighbors were primarily interested in increasing yields from depleted soils, but environmental benefits have come along as part of the bargain. According to Johan Arvidsson, professor of soil physics at the Swedish University of Agricultural Sciences, the plow-free growing project reduces nitrogen leaching that causes over-fertilization of nearby waterways.

And with the rising costs of agricultural inputs, plow-free cultivation can save money on fuel, machinery and labor. However, the amount of chemical fertilizers and pesticides used is about the same.

“We consume about half as much fuel per hectare today, compared to before we went over to this system in the 1970s,” Andersson says. “At the same time, we have increased yields and cut working hours by about half.”

According to Professor Arvidsson, it’s crucial that plow-free methods achieve harvests at least comparable to traditional practices, because the energy input in the form of tractor fuel is relatively small compared to the amount of energy in the harvest. If harvests fall, the positive environmental impact from saving fuel is quickly lost.

Attitudes outweigh technology

Plow-free cultivation is more about the mindset than the machines and tools. For example, the harvesting blades should be kept as close as possible to the ground so that the remaining straw is finely chopped. Sharp knives are a must, and the straw needs to be well spread so that string piles aren’t left behind. Wider tires are preferable to avoid deep ruts in the ground. It’s also important to rotate crops regularly, making the system unsuitable for growing straw-rich winter wheat year after year.

“We sow half the farm with winter wheat and half with spring-sown crops,” says Andersson.

Plow-free agriculture is now the dominant approach in south-central Sweden, where stiff clay soils are common. The rest of Sweden is gradually moving in a similar direction, particularly in areas with especially heavy soils. An estimated 15 to 20 percent of Sweden’s arable land is farmed with the plow-free method.

“We’ll definitely continue with plow-free cultivation,” Andersson says. “We’re constantly learning and improving, and each year is a new experience.”

Article published in December 2009