Editing Tillage (section)

==Types==
===Primary and secondary tillage ===
Primary tillage is usually conducted after the last harvest, when the soil is wet enough to allow plowing but also allows good traction. Some soil types can be plowed dry. The objective of primary tillage is to attain a reasonable depth of soft soil, incorporate crop residues, kill weeds, and to aerate the soil. Secondary tillage is any subsequent tillage, to incorporate fertilizers, reduce the soil to a finer [[tilth]], level the surface, or control weeds.<ref>{{cite web |title=Types of tillage |url=http://www.knowledgebank.irri.org/ericeproduction/I.2_Types_of_tillage.htm |website=Knowledge Bank |access-date=24 February 2019}}</ref>

===Reduced tillage===

Reduced tillage<ref group="note" name="Systems" /> leaves between 15 and 30% crop residue cover on the soil or 500 to 1000 pounds per acre (560 to 1100&nbsp;kg/ha) of small grain residue during the critical erosion period. This may involve the use of a chisel plow, field cultivators, or other implements. See the general comments below to see how they can affect the amount of residue.

===Intensive tillage===
Intensive tillage<ref group="note" name="Systems" /> leaves less than 15% [[crop residue]] cover or less than 500 pounds per acre (560&nbsp;kg/ha) of small grain residue. This type of tillage is often referred to as [[conventional tillage]], but as conservational tillage is now more widely used than intensive tillage (in the United States),<ref>{{cite web |title=CONSERVATION TILLAGE IN THE UNITED STATES: AN OVERVIEW |work=okstate.edu |url=http://agecon.okstate.edu/isct/labranza/walters/conservation.doc |publisher=Institute of Agriculture and Natural Resources, University of Nebraska – Lincoln |page=Figure 2 |access-date=8 July 2013}}</ref><ref name=CRM>{{cite web |work=ctic.purdue.edu |url=http://www.ctic.purdue.edu/CRM |title=National Crop Residue Management (CRM) Survey Summary (various years) |publisher=Conservation Technology Information Center}}</ref> it is often not appropriate to refer to this type of tillage as conventional. Intensive tillage often involves multiple operations with implements such as a mold board, disk, or chisel [[Plough|plow]]. After this, a finisher with a [[Harrow (tool)|harrow]], rolling basket, and cutter can be used to prepare the seed bed. There are many variations.

===Conservation tillage===
Conservation tillage<ref group="note" name="Systems" /> leaves at least 30% of crop residue on the soil surface, or at least 1,000&nbsp;lb/ac (1,100&nbsp;kg/ha) of small grain residue on the surface during the critical [[soil erosion]] period. This slows water movement, which reduces the amount of soil erosion. Additionally, conservation tillage has been found to benefit predatory arthropods that can enhance pest control.<ref>Tamburini, G., De Simone, S., Sigura, M., Boscutti, F., Marini, L. and Kleijn, D. (2016), Conservation tillage mitigates the negative effect of landscape simplification on biological control. ''[[Journal of Applied Ecology]]'', 53: 233–241. [[doi:10.1111/1365-2664.12544]]</ref> Conservation tillage also benefits farmers by reducing fuel consumption and soil compaction. By reducing the number of times the farmer travels over the field, significant savings in fuel and labor are made.

Conservation tillage is used on over 370 million acres, mostly in South America, Oceania and North America.<ref>{{Cite web|url=https://news.stanford.edu/2019/12/06/reduced-soil-tilling-helps-soils-yields/|title=Reduced soil tilling helps both soils and yields|last=Horton|first=Michelle|date=2019-12-06|website=Stanford News|language=en|access-date=2019-12-08}}</ref> In most years since 1997, conservation tillage was used in US cropland more than intensive or reduced tillage.<ref name="CRM" />

However, conservation tillage delays warming of the soil due to the reduction of dark earth exposure to the warmth of the spring sun, thus delaying the planting of the next year's spring crop of corn.<ref>{{cite web |url=http://www.ag.ndsu.edu/pubs/ageng/machine/AE-1370/ae1370.htm |title=Strip Till for Field Crop Production |publisher=Ag.ndsu.edu |date=2012-11-14 |access-date=2012-12-20}}</ref>

* [[No-till]] – plows, disks, et cetera are not used. Aims for 100% ground cover.
* [[Strip-till]] – Narrow strips are tilled where seeds will be planted, leaving the soil in between the rows untilled.<ref name="tce">{{cite web |title=Best Management Practices for Conservation/Reduced Tillage|url=http://publications.tamu.edu/WHEAT/PUB_wheat_Best%2520Management%2520Practices%2520for%2520Conservation%2520Tillage.pdf |publisher=Texas Cooperative Extension, The Texas A&M University System |url-status=dead |archive-url=https://web.archive.org/web/20140810225128/http://publications.tamu.edu/WHEAT/PUB_wheat_Best%20Management%20Practices%20for%20Conservation%20Tillage.pdf |archive-date=10 August 2014 }}</ref>
* [[Mulch-till]] - Soil is covered with mulch to conserve heat and moisture. 100% soil disturbance.
* Rotational tillage – Tilling the soil every two years or less often (every other year, or every third year, etc.).<ref name="tce"/>
* Ridge-till{{Explain|date=July 2021}}

===Zone tillage===
Zone tillage is a form of modified deep tillage in which only narrow strips are tilled, leaving soil in between the rows untilled. This type of tillage agitates the soil to help reduce [[soil compaction]] problems and to improve internal [[soil drainage]].<ref name="Deep Zone Tillage">[http://extension.umass.edu/vegetable/projects/deep-zone-tillage], [[University of Massachusetts Amherst]]. Vegetable Program. "Deep Zone Tillage", 2012.</ref> It is designed to only disrupt the soil in a narrow strip directly below the crop row. In comparison to no-till, which relies on the previous year's plant residue to protect the soil and aids in postponement of the warming of the soil and crop growth in Northern climates, zone tillage produces a strip approximately five inches wide that simultaneously breaks up plow pans, assists in warming the soil and helps to prepare a seedbed.<ref name="Penn State Extension">{{cite web |url=http://extension.psu.edu/on-farm/research/miller |title=Evaluation of Zone Tillage for Corn Production — On-Farm Research — Penn State Extension |access-date=2013-08-03 |url-status=dead |archive-url=https://web.archive.org/web/20130513074243/http://extension.psu.edu/on-farm/research/miller |archive-date=13 May 2013 }} [[Pennsylvania State University]]. "Evaluation of Zone Tillage for Corn Production", 2002.</ref> When combined with cover crops, zone tillage helps replace lost organic matter, slows the deterioration of the soil, improves soil drainage, increases soil water and nutrient holding capacity, and allows necessary soil organisms to survive.

It has been successfully used on farms in the Midwest and West of the US for over 40 years, and is currently used on more than 36% of the U.S. farmland.<ref name="Integrated Pest Management">{{cite web |url=http://www.hort.uconn.edu/ipm/veg/htms/dpzonetill.htm |title=UCONN IPM: Integrated Pest Management:Vegetables:Deep Zone Tillage |access-date=2013-08-03 |url-status=dead |archive-url=https://web.archive.org/web/20130522091343/http://www.hort.uconn.edu/ipm/veg/htms/dpzonetill.htm |archive-date=22 May 2013 }}, Boucher, J. [[University of Connecticut]]. "Soil Health and Deep-Zone Tillage", 2008.</ref> Some specific states where zone tillage is currently in practice are Pennsylvania, Connecticut, Minnesota, Indiana, Wisconsin, and Illinois.

Its use in the USA's Northern [[Corn Belt]] states lacks consistent yield results; however, there is still interest in deep tillage within agriculture.<ref name="Ag Answers">[http://www.agriculture.purdue.edu/AgAnswers/story.asp?storyID=1912], "Fall Zone Tillage Conserves Soil, Yields Well", 1999.</ref> In areas that are not well-drained, deep tillage may be used as an alternative to installing more expensive tile drainage.<ref name="Plant Management Network">[http://extension.umass.edu/vegetable/research-projects/deep-zone-tillage], DeJong-Hughes, J. Johnson, J. Plant Management Network. 2009.</ref>