Editing Weed control (section)

===Physical/mechanical methods===
{{See also|Mechanical weed control}}
==== Coverings ====
In a domestic gardens, methods of weed control include covering an area of ground with a material that creates an unsuitable environment for weed growth, known as a ''weed mat''. For example, several layers of wet [[newspaper]] prevent light from reaching plants beneath, which kills them.

In the case of black plastic, the [[greenhouse effect]] kills the plants. Although the black plastic sheet is effective at preventing weeds that it covers, it is difficult to achieve complete coverage. Eradicating persistent perennials may require the sheets to be left in place for at least two seasons.{{Citation needed|date=September 2022}}

Some plants are said to produce root exudates that suppress [[herb]]aceous weeds. ''[[Tagetes minuta]]'' is claimed to be effective against couch and ground elder,<ref>{{cite web|url=http://www.pfaf.org/user/Plant.aspx?LatinName=Tagetes+minuta|title=Tagetes minuta Muster-John-Henry PFAF Plant Database|work=pfaf.org}}</ref> whilst a border of [[comfrey]] is also said to act as a barrier against the invasion of some weeds including couch.
A {{convert|5|–|10|cm}} layer of [[Woodchips|wood chip]] [[mulch]] prevents some weeds from sprouting.

[[Gravel]] can serve as an inorganic mulch.

[[Irrigation]] is sometimes used as a weed control measure such as in the case of [[paddy fields]] to kill any plant other than the water-tolerant rice crop.

==== Manual removal ====
[[File:Weeding (499719425).jpg|thumb|Tools used for amateur weeding include spades and gloves]]
[[File:Weeding.jpg|thumb|Weeds are removed manually in large parts of India.]]

Many gardeners still remove weeds by manually pulling them out of the ground, making sure to include the roots that would otherwise allow some to re-sprout.

Hoeing off weed leaves and stems as soon as they appear can eventually weaken and kill perennials, although this will require persistence in the case of plants such as bindweed. Nettle infestations can be tackled by cutting back at least three times a year, repeated over a three-year period. Bramble can be dealt with in a similar way.

A highly successful, mostly manual, removal programme of weed control in natural bush land has been the control of [[sea spurge]] by [[Sea Spurge Remote Area Teams]] in [[Tasmania]].<ref>{{cite web |url=http://www.parks.tas.gov.au/file.aspx?base=41336 |title=EVALUATION REPORT DECEMBER 2015 - Wildcare SPRATS volunteer weed eradication project |publisher=Tasmanian Parks and Wildlife Service |access-date=19 June 2017}}</ref>

==== Tillage ====

[[File:00DI0874 - Flickr - USDAgov (1).jpg|thumb|Weed control through tilling with hoes, circa 1930-40s]]

[[Plough]]ing includes tilling of soil, intercultural ploughing and summer ploughing. Ploughing uproots weeds, causing them to die. Summer ploughing also helps in killing pests.

[[File:Dwarswieder.jpg|thumb|A mechanical weed control device]]

Mechanical tilling with various types of [[cultivator]]s can remove weeds around crop plants at various points in the growing process.

An [[Aquamog]], an [[aquatic weed harvester]], can be used to remove weeds covering a body of water.<ref>{{cite web |title=Aquamogs |date=21 June 2011 |url=http://aquamog.net/aquamogs/aquamogs/ |access-date=November 22, 2018}}</ref>

==== Thermal ====
[[File:Speicherkoog Kartoffelacker Abflammgerät Envo-Dan.jpg|thumb|Pesticide-free thermic weed control with a weed burner on a potato field in [[Dithmarschen]], Germany]]
Several thermal methods can control weeds.

{{visible anchor|Flame weeding}} uses a [[flame]] several centimetres/inches away from the weeds to singe them, giving them a sudden and severe heating.<ref name="Vougioukas-2019">{{cite journal | last=Vougioukas | first=Stavros G. | title=Agricultural Robotics | journal=[[Annual Review of Control, Robotics, and Autonomous Systems]] | publisher=[[Annual Reviews (publisher)|Annual Reviews]] | volume=2 | issue=1 | date=2019-05-03 | issn=2573-5144 | doi=10.1146/annurev-control-053018-023617 | pages=365–392| s2cid=242732172 | doi-access=free }}</ref> The goal of flame weeding is not necessarily burning the plant, but rather causing a lethal [[wilting]] by [[denaturation (biochemistry)|denaturing proteins]] in the weed. Similarly, hot air weeders can heat up the seeds to the point of destroying them.  Flame weeders can be combined with techniques such as stale seedbeds (preparing and watering the seedbed early, then killing the nascent crop of weeds that springs up from it, then sowing the crop seeds) and pre-emergence flaming (doing a flame pass against weed seedlings after the sowing of the crop seeds but before those seedlings emerge from the soil—a span of time that can be days or weeks).

Hot foam causes the cell walls to rupture, killing the plant. Weed burners heat up soil quickly and destroy superficial parts of the plants. Weed seeds are often heat resistant and even react with an increase of growth on dry heat.

Since the 19th century [[soil steam sterilization]] has been used to clean weeds completely from soil. Several research results confirm the high effectiveness of humid heat against weeds and its seeds.<ref>Research report of DLR Rheinlandpfalz, September 2010: [http://www.soil-steaming-steam-boiler-blog.com/wp-content/uploads/2010/10/steaming-research-results_dlr2010.pdf ''Weed control in seed cultures, especially arugula''] {{Webarchive|url=https://web.archive.org/web/20150924103450/http://www.soil-steaming-steam-boiler-blog.com/wp-content/uploads/2010/10/steaming-research-results_dlr2010.pdf |date=2015-09-24 }}, Author: Dr. Norbert Laun, Institute "Queckbrunnerhof", Schifferstadt (Germany). Viewed on 14. February 2011.</ref>

[[Soil solarization]] in some circumstances is very effective at eliminating weeds while maintaining grass. Planted grass tends to have a higher heat/humidity tolerance than unwanted weeds.{{citation needed|date=January 2021}}

==== Lasers ====
In [[precision agriculture]], novel [[agricultural robot]]s and machines can [[agricultural technology|use lasers]] for weed control, called "laserweeding".<ref name="interestingengineeringPapadopoulos">{{cite news |last1=Papadopoulos |first1=Loukia |title=This new farming robot uses lasers to kill 200,000 weeds per hour |url=https://interestingengineering.com/innovation/farming-robot-lasers-200000-weeds-per-hour |access-date=17 November 2022 |work=interestingengineering.com |date=21 October 2022}}</ref> Their benefits may include "healthier crops and [[soil conservation|soil]], decreased herbicide use, and reduced chemical and labor costs".<ref name="interestingengineeringPapadopoulos"/>

==== Seed targeting ====
In 1998, the Australian Herbicide Resistance Initiative debuted. gathered fifteen scientists and technical staff members to conduct field surveys, collect seeds, test for resistance and study the biochemical and genetic mechanisms of resistance. A collaboration with [[DuPont]] led to a mandatory herbicide labeling program, in which each mode of action is clearly identified by a letter of the alphabet.<ref name=s1408/>

The key innovation of the Australian Herbicide Resistance Initiative has been to focus on weed seeds. Ryegrass seeds last only a few years in soil, so if farmers can prevent new seeds from arriving, the number of sprouts will shrink each year. Until the new approach farmers were unintentionally helping the seeds. Their combines loosen ryegrass seeds from their stalks and spread them over the fields. In the mid-1980s, a few farmers hitched covered trailers, called "chaff carts", behind their combines to catch the chaff and weed seeds. The collected material is then burned.<ref name=s1408/>

An alternative is to concentrate the seeds into a half-meter-wide strip called a [[windrow]] and burn the windrows after the harvest, destroying the seeds. Since 2003, windrow burning has been adopted by about 70% of farmers in Western Australia.<ref name=s1408/>

Yet another approach is the Harrington Seed Destructor, which is an adaptation of a coal pulverizing cage mill that uses steel bars whirling at up to 1500 rpm. It keeps all the organic material in the field and does not involve combustion, but kills 95% of seeds.<ref name=s1408/>