Editing Rice (section)

== Agronomy ==

=== Growing ===

Like all crops, rice depends for its growth on both biotic and abiotic environmental factors. The principal biotic factors are crop variety, [[Pest (organism)|pests]], and [[plant disease]]s. Abiotic factors include the soil type, whether lowland or upland, amount of rain or irrigation water, temperature, [[Photoperiodism|day length]], and intensity of sunlight.<ref name="Verheye 2010">{{cite book |last=Beighley |first=Donn H. |title=Soils, Plant Growth and Crop Production Volume II |chapter=Growth and Production of Rice |editor-last=Verheye |editor-first=Willy H. |date=2010 |publisher=[[EOLSS]] Publishers |isbn=978-1-84826-368-0 |url=https://www.eolss.net/ebooklib/bookinfo/soils-plant-growth-crop-production.aspx |page=49 |archive-date=May 11, 2021 |access-date=November 28, 2020 |archive-url=https://web.archive.org/web/20210511044506/https://www.eolss.net/ebooklib/bookinfo/soils-plant-growth-crop-production.aspx |url-status=live }}</ref>

Rice grains can be planted directly into the field where they will grow, or seedlings can be grown in a seedbed and transplanted into the field. Direct seeding needs some 60 to 80&nbsp;kg of grain per hectare, while transplanting needs less, around 40&nbsp;kg per hectare, but requires far more labour.<ref name="IRRI planting">{{cite web |url=http://www.knowledgebank.irri.org/step-by-step-production/growth/planting |title=How to plant rice |publisher=[[International Rice Research Institute]] |access-date=December 29, 2023 }}</ref> Most rice in Asia is transplanted by hand. Mechanical transplanting takes less time but requires a carefully-prepared field and seedlings raised on mats or in trays to fit the machine.<ref name="IRRI transplanting">{{cite web |url=http://www.knowledgebank.irri.org/step-by-step-production/growth/planting/transplanting |title=Transplanting |publisher=[[International Rice Research Institute]] |access-date=December 29, 2023 }}</ref> Rice does not thrive if continuously submerged.<ref name="Cornell 2011">{{cite web |last=Uphoff |first=Norman |url=http://ciifad.cornell.edu/sri/extmats/philmanual.pdf |title=More rice with less water through SRI - the System of Rice Intensification |publisher=[[Cornell University]] |archive-url=https://web.archive.org/web/20111226111455/https://ciifad.cornell.edu/sri/extmats/philmanual.pdf |archive-date=December 26, 2011 |access-date=May 13, 2012 }}</ref> Rice can be grown in different environments, depending upon water availability. The usual arrangement is for lowland fields to be surrounded by [[Bunding|bunds]] and flooded to a depth of a few centimetres until around a week before harvest time; this requires a large amount of water. The "alternate wetting and drying" technique uses less water. One form of this is to flood the field to a depth of 5&nbsp;cm (2&nbsp;in), then to let the water level drop to 15&nbsp;cm (6&nbsp;in) below surface level, as measured by looking into a perforated field water tube sunk into the soil, and then repeating the cycle.<ref name="IRRI water mgmt">{{cite web |url=http://www.knowledgebank.irri.org/step-by-step-production/growth/water-management |title=Water Management |publisher=[[International Rice Research Institute]] |access-date=November 4, 2023 |archive-date=November 4, 2023 |archive-url=https://web.archive.org/web/20231104113412/http://www.knowledgebank.irri.org/step-by-step-production/growth/water-management |url-status=live }}</ref> [[Deepwater rice]] varieties tolerate flooding to a depth of over 50 centimetres for at least a month.<ref>{{cite book |last=Catling |first=David |chapter=Deepwater Rice Cultures in the Ganges-Brahmaputra Basin |title=Rice in Deep Water |publisher=[[International Rice Research Institute]] |year=1992 |chapter-url=https://books.google.com/books?id=N5JxwKx1RAgC&pg=PA230 |isbn=978-971-22-0005-2 |page=2}}</ref> [[Upland rice]] is grown without flooding, in hilly or mountainous regions; it is [[rainfed]] like wheat or maize.<ref>{{cite book |last1=Gupta |first1=Phool Chand |last2=O'Toole |first2=J. C. O'Toole |year=1986 |title=Upland Rice: A Global Perspective |publisher=[[International Rice Research Institute]] |isbn=978-971-10-4172-4}}</ref>

{{multiple image |align=center |caption_align=center |total_width=840 |image_gap=10 |image_style=border:none;
|image1=Kerbau Jawa.jpg |caption1=Ploughing a rice terrace with [[Domestic buffalo|water buffaloes]] in [[Java]]
|image2=Cambodian farmers planting rice.jpg |caption2=Farmers planting rice by hand in [[Cambodia]]
|image3=Rice-planting-machine 2,katori-city,japan.JPG |caption3=Mechanised rice planting in Japan
|image4=Pana Banaue Rice Terraces (Cropped).jpg |caption4=Ancient mountainside [[Banaue Rice Terraces|rice terraces at Banaue]], Philippines
}}

=== Harvesting ===

Across Asia, unmilled rice or "paddy" (Indonesian and Malay {{lang|id|padi}}), was traditionally the product of [[smallholder]] agriculture, with manual [[harvest]]ing. Larger farms make use of machines such as [[combine harvester]]s to reduce the input of labour.<ref name="IRRI Harvesting systems">{{cite web |title=Harvesting systems |url=http://www.knowledgebank.irri.org/step-by-step-production/postharvest/harvesting/harvesting-systems |publisher=[[International Rice Research Institute]] |access-date=January 3, 2024 |archive-date=January 3, 2024 |archive-url=https://web.archive.org/web/20240103095241/http://www.knowledgebank.irri.org/step-by-step-production/postharvest/harvesting/harvesting-systems |url-status=live }}</ref> The grain is ready to harvest when the moisture content is 20–25%. Harvesting involves [[reaping]], stacking the cut stalks, [[threshing]] to separate the grain, and cleaning by [[winnowing]] or [[sieve|screening]].<ref name="IRRI Harvesting">{{cite web |title=Harvesting |url=http://www.knowledgebank.irri.org/step-by-step-production/postharvest/harvesting#guidelines-on-proper-harvesting |publisher=[[International Rice Research Institute]] |access-date=December 6, 2023 |archive-date=December 6, 2023 |archive-url=https://web.archive.org/web/20231206070736/http://knowledgebank.irri.org/step-by-step-production/postharvest/harvesting#guidelines-on-proper-harvesting |url-status=live }}</ref> The rice grain is dried as soon as possible to bring the moisture content down to a level that is safe from mould fungi. Traditional drying relies on the heat of the sun, with the grain spread out on mats or on pavements.<ref name="IRRI Drying">{{cite web |title=Drying |url=http://www.knowledgebank.irri.org/step-by-step-production/postharvest/drying |publisher=[[International Rice Research Institute]] |access-date=December 6, 2023}}</ref>

{{multiple image |align=center |caption_align=center |total_width=840 |image_gap=10 |image_style=border:none; 
|image1=Rice-combine-harvester, Katori-city, Japan.jpg |caption1=Rice [[combine harvester]] in [[Chiba Prefecture]], Japan 
|image2=Rice farmers Mae Wang Chiang Mai Province.jpg |caption2=After the harvest, rice straw is gathered in the traditional way from small paddy fields in [[Mae Wang]], Thailand
|image3=NP India burning 48 (6315309342).jpg |caption3=Burning of rice residues to prepare the land for [[wheat]] planting in [[Sangrur]], India
|image4=Nellu.JPG |caption4=Drying rice in [[Peravoor]], India
}}