Scientists find that less tilling means more earthworms

Anecic earthworms live deep in the soil and emerge at night, providing a helpful mixing of soil in agricultural fields. (The Earthworm Society of Britain)
Jenna Ladd | May 16, 2017

Wriggly earthworms are the unsung heroes of agricultural fields around the world. Their tiny bodies make it easier for water and air to enter the soil, transform organic matter into nutrients that is available to plants and can improve crop productivity by more than 50 percent.

A study recently published in the journal Global Change Biology sought to better understand which agricultural conditions are optimal for worms. Dr. Olaf Schmidt and Dr. Maria Briones analyzed 215 studies from over 40 countries that explored the relationship between tilling practices and worm population health.

The meta-analysis showed that disturbing the soil less (i.e. no-till farming, conservation agriculture) resulted in significantly more abundant earthworm populations. For example, no-till farmland saw a 137 percent increase in worm populations and a nearly 200 percent increase in soil biomass. Those areas of land in reduced-till for more than ten years saw the most earthworms return to the soil. In contrast, those field that were heavily plowed lost half of their original worm population.

Researchers observed the affect of tilling on 13 species of worms and found that the largest species were most heavily impacted. These creatures, called anecic earthworms, live deep down in the soil. At night-time they wriggle up a single channel, grab food, such as plant matter or manure, and then slide back down the same permanent burrow.

The researchers write that restoring earthworm populations through practing reduced-till or no-till farming “will ensure the provision of ecosystem functions such as soil structure maintenance and nutrient cycling by “nature’s plow.””

Western Iowa celebrates no-till farming

Environmental organizations around Iowa continue to stress the merits of no-till farming to Iowans. The Daily Nonpareil reports that June 14 will mark the fourth annual Western Iowa No-Till Field Day.

Held near Shelby, Iowa, the field day is hosted by Iowa State University Extension, Natural Resources Conservation Service and Soil and Water Conservation districts in Pottawattamie, Shelby and Harrison counties.

The focal points of the field day are educating Iowans on both the conservation and production yield benefits of no-till:

Shelby County Iowa State Extension program coordinator Kate Olson explained that no-till improves soil structure, solidifying and strengthening the earth. The stronger soil also holds more nutrients and limits water runoff, which helps prevent fertilizer from reaching bodies of water.

“No-till keeps the soil on the field instead of in neighboring lakes and streams,” she said. “The practice really does protect soil and water and prevents pollution.”

Conservationist Kevin Kuhn further explains the impact of no-till farming over time.

The less runoff, the less soil erosion, said Kevin Kuhn, an area resource conservationist at the NRCS office in Atlantic who will work at the field day. Farmland worked with long-term no-till practices, over about seven to eight years, will retain three-times more soil than similar land with tillage, he said.

“We really feel that long-term no-till farming is our best conservation practice in Iowa,” Kuhn said. “Through a field day, we want to do everything we can to promote long-term no-till so producers understand the impact it has on conservation. And we want to help farmers be successful at it.”

Earlier this year, the Iowa Environmental Focus featured a radio spot and blog post on the potential of no-till farming to limit greenhouse gas emissions.

Further explanations of no-till farming’s advantages are explained in the video below via SUNUP.

On the Radio: Untilled fields mean less air pollution

Listen to this week’s radio segment on the environmental benefits of no-till farming.

For an in-depth description of no-till farming and of how farmers will need to adopt the practice to meet increased food demands of the future, see this video published by The EconomistContinue reading

Study: No-Till Farming Limits Greenhouse Gases

Credit: USDA

No-till farming does more than just improve soil quality and reduce erosion. It can help fight global warming too, a Purdue University study has found.

No-till fields in the study released 57 percent less nitrous oxide – a greenhouse gas 310 more potent than carbon dioxide – than chisel-tilled fields and 40 percent less gas than fields tilled with moldboard plows.

The practice can also help save farmers money because it slows the breakdown of costly fertilizers in the soil.

Read the AP report.