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No-till farming, also known as conservation tillage or zero tillage is a way of growing crops from year to year without disturbing the soil through tillage. It is becoming more common as researchers study its effects and farmers uncover its economic benefits.

Process

Producing crops usually involves regular tilling that agitates the soil in various ways, usually with tractor-drawn implements. Tilling is used to remove weeds, mix in soil amendments like fertilizers, shape the soil into rows for crop plants and furrows for irrigation, and prepare the surface for seeding. This can lead to unfavorable effects, like soil compaction; loss of organic matter; degradation of soil aggregates; death or disruption of soil microbes, arthropods, and earthworms; and soil erosion where topsoil is blown or washed away.

Effects on Soil

In no-till farming the soil is left intact and crop residues are left in the fields. Variations of the conservation tillage method involve some working of the soil with attention paid to keeping soil compaction and carbon loss at a minimum. These variations include reduced tillage, in which small strips may be plowed to allow space for planting seeds. Other terms, such as incomplete tillage and minimal tillage may be used.

Pros and Cons

There are benefits and drawbacks to no-till and reduced tillage. The benefit currently receiving much scientific attention is the potential for carbon sequestration in the soil of crop fields. When soil is tilled with machinery carbon is released from the soil into the atmosphere. This, in addition to the emissions from the farm equipment itself, increases the carbon dioxide content of the atmosphere. Carbon sequestration, in soil or elsewhere, is a proposed method of reducing these greenhouse gases. Cropland soil is an ideal carbon sink, since in most areas it has been depleted of its necessary carbon content. Traditional farming practices that rely on tillage have removed carbon from the soil ecosystem. Removal of crop residues also deprives a field of a good source of carbon. By reducing tillage, leaving crop residues to decompose where they lie, and growing winter cover crops such as grains or alfalfa, a farmer can slow carbon loss from a field while doing a small part to transfer carbon from the atmosphere to the soil.

Further Benefits

Other benefits of no-till include increasing soil quality (soil function), protecting the soil from erosion, evaporation of water, and structural breakdown. Crop residues left intact help both natural precipitation and irrigation water infiltrate the soil where it can be used. The crop residue left on the soil surface also limits evaporation, conserving water for plant growth. A reduction in tillage passes helps prevent the soil aggregates from being crushed and/or compacted. Less tillage of the soil reduces labor and related fuel and machinery costs. Less soil plowing means less airborne dust, which is a serious pollutant in some agricultural areas. No-till fields often have more beneficial insects and annelids, a higher microbial content, and a greater amount of soil organic material. As sustainable agriculture becomes more socially popular, monetary grants and awards are becoming readily available to farmers who practice conservation tillage. Some large energy corporations which are among the greatest generators of fossil-fuel-related pollution are willing to purchase carbon credits to encourage farmers to engage in conservation tillage. The farmers' land essentially becomes a carbon sink for the power generators' emissions. This helps the farmer in several ways, and it helps the energy companies meet demands for reduction of pollution.

Disadvantages

The disadvantage of no-till farming is the need for specialized seeding equipment designed to plant seeds into undisturbed soil and crop residues. However, today many types of no-till seeding equipment are readily available. If no-till farming is practiced properly, including crop residue management at harvest and a diverse crop rotation the use of pesticides and fertilizers often is less than traditional tillage based methods of crop production. Because of a dependence on a “burn-down” herbicide such as Glyphosate in lieu of tillage for seedbed preparation, no-till is often wrongly associated with increased pesticide use in comparison to traditional tillage based methods of crop production. Because there is often a slight increase in soil bulk density associated with no-till farming there is a misconception that periodic tillage is necessary to “fluff” the soil back up. There are millions of acres of land that have been no-tilled for over 20 years where water infiltration, biologic activity, soil aggregate stability, and productivity have all increased well beyond nearby traditionally tilled land. No-till farming mimics the natural conditions under which most soils formed more so than any other method of farming in that the soil is left undisturbed except to place seeds in a position to germinate.

Potential

Research by both institutions and farmers continues into developing organic no-till farming methods that utilize the rolling/crimping of cover crops and diverse crop rotations to suppress weeds, insects, and diseases. Current organic farming methods often rely on excessive tillage to control these pests at the expense of soil quality. The marriage of no-till and organic has the potential to produce both the healthiest food and the healthiest soil at the same time.

See also

External links

  • http://www.mandakzerotill.org/
  • http://www.ctic.purdue.edu/CTIC/CTIC.html
  • http://www.cedarmeadowfarm.com/
  • http://www.gcta-ga.org/
  • http://www.lesspub.com/cgi-bin/site.pl?ntf/index
  • http://www.ars.usda.gov/main/site_main.htm?modecode=54-45-00-00
  • http://www.mbzerotill.com/
  • http://soils.usda.gov/sqi/
  • http://www.no--till.com/switchboard.htm
  • http://www.notill.org/
  • http://www.sdnotill.com/
  • http://css.wsu.edu/links/no_till.htm
  • http://www.wantfa.com.au/
  • http://www.cfi.org.au/
  • http://www.msfp.org.au/
  • http://www.dakotalakes.com/
  • http://www.soilhealth.com/
  • http://pnwsteep.wsu.edu/
  • http://res2.agr.ca/lethbridge/index_e.htm
  • http://www.agr.gc.ca/pfra/main_e.htm
  • http://www.newfarm.org/index.shtml

Further reading

Wright, Sylvia. "Paydirt." UC Davis Magazine Winter 2006, pp 24-27.

Agronomy | Agricultural soil science

 

This article is licensed under the GNU Free Documentation License. It uses material from the "No-till farming".

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