Editing Organic farming (section)

=== Weed management ===

Organic [[weed]] management promotes weed suppression, rather than weed elimination, by enhancing crop competition and [[phytotoxic]] effects on weeds.<ref name="extension.iastate.edu">Kathleen Delate and Daksh Bhavsar. 2013. [http://www.extension.iastate.edu/Publications/PM1883.pdf Weed Management for Organic Farmers]. Iowa State University Extension Bulletin 1883.</ref> Organic farmers integrate cultural, biological, mechanical, physical and chemical tactics to manage weeds without synthetic [[herbicide]]s.

Organic standards require [[Crop rotation|rotation]] of annual crops,<ref>Staff, India's Conference on Trade and Development. [http://193.194.138.42/en/Sustainability-Claims-Portal/Discussion-Forum/Organic-Standards/ Organic Standards] {{Webarchive|url=https://web.archive.org/web/20150606214740/http://193.194.138.42/en/Sustainability-Claims-Portal/Discussion-Forum/Organic-Standards/ |date=6 June 2015 }}</ref> meaning that a single crop cannot be grown in the same location without a different, intervening crop. Organic crop rotations frequently include weed-suppressive [[cover crop]]s and crops with dissimilar life cycles to discourage weeds associated with a particular person.<ref name="extension.iastate.edu"/> Research is ongoing to develop organic methods to promote the growth of natural microorganisms that suppress the growth or germination of common weeds.<ref>{{cite journal | last1 = Kremer | first1 = Robert J. | last2 = Li | first2 = Jianmei | year = 2003 | title = Developing weed-suppressive soils through improved soil quality management | url = http://naldc.nal.usda.gov/download/11123/PDF | journal = Soil & Tillage Research | volume = 72 | issue = 2 | pages = 193–202 | doi = 10.1016/s0167-1987(03)00088-6 | bibcode = 2003STilR..72..193K | access-date = 3 February 2013 | archive-date = 3 March 2016 | archive-url = https://web.archive.org/web/20160303172306/http://naldc.nal.usda.gov/download/11123/PDF | url-status = dead }}</ref>

Other cultural practices used to enhance crop competitiveness and reduce weed pressure include selection of competitive crop varieties, high-density planting, tight row spacing, and late planting into warm soil to encourage rapid crop [[germination]].<ref name="extension.iastate.edu"/>

Mechanical and chemical weed control practices used on organic farms can be broadly grouped as:<ref name="extension.org">Mark Schonbeck, Virginia Association for Biological Farming. Last Updated: 23 March 2010. [http://www.extension.org/article/18532 An Organic Weed Control Toolbox] {{Webarchive|url=https://web.archive.org/web/20100828064035/http://www.extension.org/article/18532 |date=28 August 2010 }}.</ref>

* [[Tillage]] - Turning the soil between crops to incorporate crop residues and soil amendments; remove existing weed growth and prepare a seedbed for planting; turning soil after seeding to kill weeds, including [[cultivator|cultivation]] of row crops.
* Mowing and cutting - Removing top growth of weeds.
* Flame weeding and thermal weeding - Using heat to kill weeds.
* [[Mulch]]ing - Blocking weed emergence with organic materials, plastic films, or [[landscape fabric]].<ref>{{cite book|author=Szykitka, Walter|title=The Big Book of Self-Reliant Living: Advice and Information on Just About Everything You Need to Know to Live on Planet Earth|publisher=Globe-Pequot|year=2004|isbn=978-1-59228-043-8|page=343|url={{google books |plainurl=y |id=E0bb14gPCZsC|page=343}}}}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Some naturally sourced chemicals are allowed for herbicidal use. These include certain formulations of [[acetic acid]] (concentrated vinegar), [[corn gluten meal]], and [[essential oils]]. A few selective [[bioherbicide]]s based on fungal [[pathogen]]s have also been developed. At this time, however, organic herbicides and [[bioherbicide]]s play a minor role in the organic weed control toolbox.<ref name="extension.org"/>

Weeds can be controlled by grazing. For example, geese have been used successfully to weed a range of organic crops including cotton, strawberries, tobacco, and corn,<ref>Glenn Geiger and Harold Biellier. 1993. [http://extension.missouri.edu/publications/DisplayPub.aspx?P=G8922 Weeding With Geese] {{Webarchive|url=https://web.archive.org/web/20100923222023/http://extension.missouri.edu/publications/DisplayPub.aspx?P=G8922 |date=23 September 2010 }}. University of Missouri Extension Bulletin G8922.</ref> reviving the practice of keeping [[Cotton Patch Goose|cotton patch geese]], common in the southern U.S. before the 1950s. Similarly, some rice farmers introduce ducks and fish to wet [[paddy field]]s to eat both weeds and insects.<ref name="csmonitor.com">[http://www.csmonitor.com/2003/0220/p11s01-sten.html?s=widep How to feed the world] By Laurent Belsie (edition of 20 February 2003) The Christian Science Monitor</ref>