Yields Improve When Farming Mimics Nature

7/27/2013 7:00 AM
By Philip Gruber Staff Writer

WILLOW STREET, Pa. — A third way is developing for farmers who are unsatisfied with both tilled and no-till land-management strategies.

Eco farming practices are designed to mimic the way the natural world grows plants, Ohio State Extension researcher Jim Hoorman told members of the Pennsylvania No-Till Alliance on July 16.

With Pennsylvania Secretary of Agriculture George Greig in attendance, the alliance was gathered at Future View Farm for the first of three field days held across the state last week.

Eco farming, which is short for ecological farming, is a no-till system, but its goal is to keep plants on the field year-round, Hoorman said.

The soil in modern fields, which are often covered less than 100 days a year, contrasts starkly with pristine prairie soil. Prairies may have 1,000-2,000 times more microbes below the surface than tilled ground.

Plant roots use hormones to attract helpful bacteria, fungi, nematodes and protozoa that help the plants grow, he said.

Eco farming uses no-till practices because they avoid the unnatural “turmoil of tillage,” which takes a natural-disaster-esque toll on soil ecosystems, he said.

Thanks to their small size, bacteria can survive in and dominate tilled land. Fungus colonies, on the other hand, live by branching out and relying on continuity for their strength. Tilling fungi is “like cutting off limbs,” Hoorman said.

York County dairy farmer Leroy Bupp agrees.

“There’s not much life in conventional soil because we kill it every year. We don’t give it a chance to grow,” he said in a separate presentation.

Bupp gave several demonstrations of tilled and no-till soil using real manure in a runoff simulation. In his sometimes humorous presentation, he said humans can easily underestimate the importance of microbes in a field.

“There is as much soil life in an acre to weigh as much as a cow, to eat as much as a cow,” he said, brandishing a plastic toy cow to reinforce his point.

Fungi help roots access 20 percent of the surrounding soil volume. Without assistance from the fungus, the roots can only draw nutrition from 1 percent of their area, Hoorman said.

The sugars the plants produce feed the microbes. Even in the winter, keeping living plants on the soil will keep the soil warm and the tiny organisms alive.

Using cover crops when the soil is not in main crop production can achieve many of the benefits of tillage without the damaging effects of turning the soil, Hoorman said.

Cover crops, whether living or killed and left as mulch, suppress weeds and keep nutrients in the soil.

While tilling adds oxygen to the soil, it also releases to the atmosphere nitrogen and phosphorus that are in the right form for plants to use. It also expends carbon dioxide, which removes vital carbon from the ground.

When white settlers first farmed in the Untied States, the land was black, especially in places like Iowa where a lot of organic matter had built up. Since then, the nation has lost 60 to 80 percent of the organic matter in its soil.

Iowa had an advantage over Pennsylvania because the prairie grasses turned over annually, while the chestnut trees that anchored Pennsylvania’s old-growth forests changed perhaps every century.

Mimicking the prairie remains an effective model for Mid-Atlantic farmers, Hoorman said.

Healthy soil rich in organic matter and pushed up by roots can be 6 to 9 inches higher than adjacent soil that has been reduced to less useful clay.

“You can actually smell the difference” between healthy soil and less healthy soil, he said. Certain bacteria give fertile soil its earthy smell, while paler and less vital soil will smell stale or not have an odor.

Soil should ideally be 50 percent pore space to allow room for air and water to permeate, he said. Negatively charged clay, by contrast, combines with calcium, magnesium and potassium and bakes into a less porous material that sheds water instead of absorbing it.

As carbon and water content decrease and the soil compacts, it becomes less productive, Hoorman said.

To increase soil fertility, plant roots are key, he said. Taller cover crops can have roots that equal the above-ground height of the plant, and the roots keep carbon and oxygen in the ground.

Increasing soil organic matter by 1 percent equals roughly $900 in nutrients. Most of that value comes from nitrogen, which is usually spread through sidedressing applications that overloads the soil because the process is only 30 to 40 percent effective, Hoorman said.

Existing organic material is 50 percent effective at providing nitrogen, while organic fertilizer is most effective, 70 to 80 percent, because microbes do not have to do extra work to put the nitrogen in a useable state.

Forty tons of organic residue per acre decomposed to 10 tons will give a 1 percent increase in soil organic content, he said.

Using no-till without cover crops leaves exposed land more vulnerable to nutrient loss through runoff. It can also create macropores, spaces in the soil where water moves too fast and carries nutrients away with it. The roots of cover crops act as a “biological plug” that slows water down in the soil, he said.

Roots can also break up compaction caused by tractor tires, gravity and rain, which can strike the earth at speeds up to 35 mph.

Over a 20-year period, a no-till field will produce only 7 inches of runoff from 1,400 inches of rain, he said.

Hoorman said the Great Plains did not have a runoff problem before they were farmed, even though as many as 60 million bison lived on the grasslands in the early 1800s.

“Did the bison stop eating or pooping in the winter?” he asked.

The plant roots absorbed the manure before it could contaminate waterways, he said.

Imitating nature by planting cover crops provides the same benefits today as the tallgrass sea provided then, he said. The plants keep nutrients on the land, enriching, revitalizing and preserving the soil.

Hoorman touted an innovative and counterintuitive approach to planting that he said can also help keep continuous plant coverage of the soil — planting main crops into living cover crops.

The tractor and planter knock down much of the cover during the planting, and an herbicide application properly timed after the seeding will eliminate weed problems and help keep the soil moist.

Killing the cover crop before planting the main crop can trap excess water at the soil and leave the land temporarily barren, defeating the purpose of eco farming. Planting into dead cover crops can also cause the plants to wrap or bind the planter, which does not happen when planting into living plants.

Spraying at the right time after planting will ensure the young corn or soybeans do not have to compete with the mature ryegrass or other cover.

Host farmer Jeff Frey asked Hoorman if planting into cover crops could lead to the “green bridge,” in which microbes jump to the young corn after the cover crop starts to decompose.

Hoorman said that while experts used to advise waiting two to three weeks after planting to spray the cover, research now suggests that it is better to wait to spray until the corn is up enough to weather the attacks.

“It’s not that the green bridge has gone away. It’s that we’ve learned to better manage it,” Hoorman said.

Cover crops can also provide a haven for beneficial insects, he said. Ground beetles can eat their weight in insects in a day, but they like a flowering food source in midsummer. Buckwheat flowers 60 days after planting, he said

In a different pest management tactic, slugs love oilseed radishes, but they also get sick from eating them, Hoorman said.

“We find dead slugs where our radishes grow,” said David Brandt, a noted Ohio no-till farmer who spoke at the field day.

The long taproot on radishes also helps break up the soil. Brandt plants them three to five days before Ohio’s fly-free date. He uses 40-50 pounds of nitrogen for the crop. The plants are susceptible to flea beetles, he said.

He has found that sunflowers bring up a lot of zinc, which has saved him money on his trace element costs.

Brandt has not applied phosphorus to his fields for several years, yet his phosphorus levels are increasing. The cover crop roots have organic acids that draw the element from the soil.

Hoorman said that while Brandt will presumably have to add phosphorus again someday, the farmer plans to save on his fertilizer costs until then.

Brandt said that he never lets his cover crops go to seed or flower because that takes the nutrients out of the roots and therefore out of the soil.

Brandt has also made his fields more similar to unmanaged natural areas by growing cover crop mixtures instead of cover crop monocultures.

“I look at our cover crops as a colony,” he said.

Hoorman said that an eight- or nine-way mix can as much as double the biomass in the soil. He favors mixes that combine legumes, grasses and radishes.

Brandt has added so much organic material to his yellow clay that his topsoil is now black.

The surprised government soil scientists had to change his soil classification, Hoorman said. He said Brandt has increased his soil organic matter from 0.5 percent to 4 percent over decades of using cover crops with no-till.

“I think now I could change this picture in five years,” Brandt said, holding a close-up photo of his rich, dark soil.

Brandt uses crimson clover but not red clover, which he said drew voles and mice. Major menaces in the Buckeye State, the rodents stayed and ate his crops.

The only cover crop Brandt had strong words for was cereal rye.

“Dave Brandt can’t kill it,” he said.

Several dairymen stood up for the plant, saying it gets them lots of cheap milk.

Though planting cover crops may seem like extra work and wasted money, Brandt’s philosophy is that cover crops should always either reduce one’s inputs or improve one’s yields.

Pairing no-till with cover crops, using no fertilizer and getting only 8!-W inches of rain in Ohio’s drought-straitened 2012 season, Brandt got 236 bushels of corn per acre.

Brandt figures he could make even more money if he grazed cattle on his cover crops. Cattle are not big in Ohio, and he said he is getting late in his career to take on the extra work that livestock require.

Despite not eking the absolute most out of land with the cattle, Brandt seems to be doing something right with eco farming.

Mimicking nature, as Hoorman, the Ohio State Extension educator, suggested, may be the way of the future because it has served the earth so well in the past.

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