Editing Compost (section)

===Agriculture and gardening===
[[File:Compost steaming - detail 3.jpg|alt=Compost - detail|thumb|Compost used as fertilizer]]
On open ground for growing [[wheat]], [[Maize|corn]], [[soybean]]s, and similar crops, compost can be broadcast across the top of the soil using spreader trucks or spreaders pulled behind a tractor. It is expected that the spread layer is very thin (approximately {{cvt|6|mm}}) and worked into the soil prior to planting. Application rates of {{cvt|25|mm}} or more are not unusual when trying to rebuild poor soils or control erosion. Due to the extremely high cost of compost per unit of nutrients in the United States, on-farm use is relatively rare since rates over 4 tons/acre may not be affordable. This results from an over-emphasis on "recycling organic matter" than on "sustainable nutrients." In countries such as Germany, where compost distribution and spreading are partially subsidized in the original waste fees, compost is used more frequently on open ground on the premise of nutrient "sustainability".<ref>{{Cite web|url = http://www.landwirtschaft-mlr.baden-wuerttemberg.de/servlet/PB/show/1118971/Landinfo_Nachhaltige%20Kompostanwendung%20in%20der%20Landwirtschaft-%20Ergebnisse%20eines%20mehrj%E4hrigen%20DBU-Projektes%20aus%20Baden-W%FCrttemberg.pdf|title = Startseite|date = 7 April 2003|access-date = 23 July 2021|archive-date = 22 March 2021|archive-url = https://web.archive.org/web/20210322232906/https://www.landwirtschaft-bw.info/pb/,Lde/Startseite|url-status = dead}}</ref>

In [[plasticulture]], [[strawberries]], [[tomato]]es, [[Capsicum|pepper]]s, [[melon]]s, and other fruits and vegetables are grown under plastic to control temperature, retain moisture and control weeds. Compost may be banded (applied in strips along rows) and worked into the soil prior to bedding and planting, be applied at the same time the beds are constructed and plastic laid down, or used as a top dressing.

Many crops are not seeded directly in the field but are started in seed trays in a greenhouse. When the seedlings reach a certain stage of growth, they are [[Transplanting|transplanted]] in the field. Compost may be part of the mix used to grow the seedlings, but is not normally used as the only planting substrate. The particular crop and the seeds' sensitivity to nutrients, salts, etc. dictates the ratio of the blend, and maturity is important to insure that oxygen deprivation will not occur or that no lingering phyto-toxins remain.<ref>{{cite journal|last1=Aslam|first1=DN|last2=Vandergheynst|first2=JS|last3=Rumsey|first3=TR|year=2008|title=Development of models for predicting carbon mineralization and associated phytotoxicity in compost-amended soil|journal=Bioresour Technol|volume=99|issue=18|pages=8735–41|doi=10.1016/j.biortech.2008.04.074|pmid=18585031|bibcode=2008BiTec..99.8735A }}</ref>

Compost can be added to soil, [[coir]], or [[peat]], as a [[tilth]] improver, supplying humus and nutrients.<ref name=":6">{{Cite web|title=Benefits and Uses|url=http://web.extension.illinois.edu/homecompost/benefits.cfm|url-status=dead|archive-url=https://web.archive.org/web/20160219205407/http://web.extension.illinois.edu/homecompost/benefits.cfm|archive-date=19 February 2016|website=Composting for the Homeowner|publisher=University of Illinois}}</ref> It provides a rich growing medium as absorbent material. This material contains moisture and soluble minerals, which provide support and [[nutrient]]s. Although it is rarely used alone, plants can flourish from mixed [[soil]] that includes a mix of compost with other additives such as [[sand]], grit, bark chips, [[vermiculite]], [[perlite]], or [[clay]] granules to produce [[loam]]. Compost can be tilled directly into the soil or growing medium to boost the level of organic matter and the overall fertility of the soil. Compost that is ready to be used as an additive is dark brown or even black with an earthy smell.<ref name=":4" /><ref name=":6" />

Generally, direct seeding into a compost is not recommended due to the speed with which it may dry, the possible presence of [[phytotoxin]]s in immature compost that may inhibit germination,<ref>{{cite journal|last1=Morel|first1=P.|last2=Guillemain|first2=G.|year=2004|title=Assessment of the possible phytotoxicity of a substrate using an easy and representative biotest|journal=Acta Horticulturae|issue=644|pages=417–423|doi=10.17660/ActaHortic.2004.644.55}}</ref><ref>Itävaara et al. Compost maturity - problems associated with testing. in Proceedings of Composting. Innsbruck Austria 18-21.10.2000</ref><ref>{{cite journal|vauthors=Aslam DN, etal|year=2008|title=Development of models for predicting carbon mineralization and associated phytotoxicity in compost-amended soil.|journal=Bioresour Technol|volume=99|issue=18|pages=8735–8741|doi=10.1016/j.biortech.2008.04.074|pmid=18585031|bibcode=2008BiTec..99.8735A }}</ref> and the possible tie up of nitrogen by incompletely decomposed lignin.<ref name="compost.css.cornell.edu">{{cite web|title=The Effect of Lignin on Biodegradability - Cornell Composting|url=http://compost.css.cornell.edu/calc/lignin.html|url-status=live|archive-url=https://web.archive.org/web/20180927195626/http://compost.css.cornell.edu/calc/lignin.html|archive-date=27 September 2018|access-date=3 March 2009|work=cornell.edu}}</ref> It is very common to see blends of 20–30% compost used for transplanting [[seedlings]].

Compost can be used to increase plant immunity to diseases and pests.<ref>{{Cite journal|last1=Bahramisharif|first1=Amirhossein|last2=Rose|first2=Laura E.|year=2019|title=Efficacy of biological agents and compost on growth and resistance of tomatoes to late blight|journal=Planta|volume=249|issue=3|pages=799–813|doi=10.1007/s00425-018-3035-2|issn=1432-2048|pmid=30406411|doi-access=free|bibcode=2019Plant.249..799B }}</ref>

==== {{anchor|Compost tea}}Compost tea ====
Compost tea is made up of extracts of fermented water leached from composted materials.<ref name=":6" /><ref name="Sinha2">{{cite book|last1=Gómez-Brandón, M|title=Advances in Fertilizer Technology: Synthesis (Vol1)|last2=Vela, M|last3=Martinez Toledo, MV|last4=Insam, H|last5=Domínguez, J|date=2015|publisher=Stadium Press LLC|isbn=978-1-62699-044-9|editor1-last=Sinha, S|pages=300–318|chapter=12: Effects of Compost and Vermiculture Teas as Organic Fertilizers|editor2-last=Plant, KK|editor3-last=Bajpai, S}}</ref> Composts can be either aerated or non-aerated depending on its [[fermentation]] process.<ref name=":02">{{Cite journal |last1=St. Martin |first1=C. C.G. |last2=Brathwaite |first2=R. A.I. |date=2012 |title=Compost and compost tea: Principles and prospects as substrates and soil-borne disease management strategies in soil-less vegetable production |url=https://solvita.com/wp-content/uploads/2014/04/Compost-and-compost-tea-Principles_Martin-et-al_2012.pdf |journal=Biological Agriculture & Horticulture |volume=28 |issue=1 |pages=1–33 |doi=10.1080/01448765.2012.671516 |bibcode=2012BioAH..28....1S |issn=0144-8765 |s2cid=49226669}}</ref> Compost teas are generally produced from adding compost to water in a ratio of 1:4–1:10, occasionally stirring to release [[microbes]].<ref name=":02" />

There is debate about the benefits of aerating the mixture.<ref name="Sinha2" /> Non-aerated compost tea is cheaper and less labor-intensive, but there are conflicting studies regarding the risks of [[phytotoxicity]] and human pathogen regrowth.<ref name=":02" /> Aerated compost tea brews faster and generates more microbes, but has potential for human pathogen regrowth, particularly when one adds additional nutrients to the mixture.<ref name=":02" />

Field studies have shown the benefits of adding compost teas to crops due to organic matter input, increased nutrient availability, and increased microbial activity.<ref name=":6" /><ref name="Sinha2" /> They have also been shown to have a suppressive effect on plant pathogens<ref>{{cite book|last1=Santos, M|title=Natural products in plant pest management|last2=Dianez, F|last3=Carretero, F|publisher=CABI|year=2011|isbn=9781845936716|editor-last=Dubey, NK|location=Oxfordshire, UK Cambridge, MA|pages=242–262|chapter=12: Suppressive Effects of Compost Tea on Phytopathogens}}</ref> and soil-borne diseases.<ref name=":02" /> The efficacy is influenced by a number of factors, such as the preparation process, the type of source  the conditions of the brewing process, and the environment of the crops.<ref name=":02" /> Adding nutrients to compost tea can be beneficial for disease suppression, although it can trigger the regrowth of human pathogens like ''[[Escherichia coli|E. coli]]'' and ''[[Salmonella]].''<ref name=":02" />

==== Compost extract ====
Compost extracts are unfermented or non-brewed extracts of leached compost contents dissolved in any solvent.<ref name=":02" />

==== Commercial sale ====
Compost is sold as bagged potting mixes in garden centers and other outlets.<ref name="RHS">{{cite web|title=John Innes potting compost|url=https://www.rhs.org.uk/advice/profile?pid=952|url-status=live|archive-url=https://web.archive.org/web/20200814113532/https://www.rhs.org.uk/advice/profile?pid=952|archive-date=14 August 2020|access-date=7 August 2020|publisher=Royal Horticultural Society}}</ref><ref name=":6" /> This may include composted materials such as manure and peat but is also likely to contain loam, fertilizers, sand, grit, etc. Varieties include multi-purpose composts designed for most aspects of planting, [[John Innes compost|John Innes]] formulations,<ref name="RHS" /> grow bags, designed to have crops such as tomatoes directly planted into them. There are also a range of specialist composts available, e.g. for vegetables, orchids, houseplants, hanging baskets, roses, ericaceous plants, seedlings, potting on, etc.<ref>{{Cite web |title=Compost for Specialist Plants - Garden Advice - Westland Garden Health |url=https://www.gardenhealth.com/advice/soil-and-compost/compost-for-specialist-plants |access-date=2024-01-15 |website=Garden Health |language=en-GB}}</ref><ref>{{Cite web |title=How to choose the best compost for your plants |url=https://www.lovethegarden.com/uk-en/article/how-to-choose-the-best-compost-for-your-plants |access-date=2024-01-15 |website=Love The Garden |language=en-gb}}</ref>