[1] It has also been introduced elsewhere since the colonial era, notably in northern Italy, the Camargue in France,[2] and in Spain, particularly in the Albufera de València wetlands in the Valencian Community, the Ebro Delta in Catalonia and the Guadalquivir wetlands in Andalusia, as well as along the eastern coast of Brazil, the Artibonite Valley in Haiti, Sacramento Valley in California, and West Lothian in Scotland among other places.
The first is in the lower Yangtze River, believed to be the homelands of the pre-Austronesians and possibly also the Kra-Dai, and associated with the Kuahuqiao, Hemudu, Majiabang, Songze, Liangzhu, and Maquiao cultures.
[7][8][9][10][11] The second is in the middle Yangtze River, believed to be the homelands of the early Hmong-Mien speakers and associated with the Pengtoushan, Nanmuyuan, Liulinxi, Daxi, Qujialing, and Shijiahe cultures.
The number of settlements among the Yangtze cultures and their sizes increased, leading some archeologists to characterize them as true states, with clearly advanced socio-political structures.
[18][20][21] The spread of japonica rice cultivation and paddy field agriculture to Southeast Asia started with the migrations of the Austronesian Dapenkeng culture into Taiwan between 3500 and 2000 BC.
[9] From about 2000 to 1500 BC, the Austronesian expansion began, with settlers from Taiwan moving south to migrate to Luzon in the Philippines, bringing rice cultivation technologies with them.
From Luzon, Austronesians rapidly colonized the rest of Maritime Southeast Asia, moving westwards to Borneo, the Malay Peninsula and Sumatra; and southwards to Sulawesi and Java.
The Austronesian Lapita culture also came into contact with the non-Austronesian (Papuan) early agriculturists of New Guinea and introduced wetland farming techniques to them.
[22] Rice and wet-field agriculture were also introduced to Madagascar, the Comoros, and the coast of East Africa around the 1st millennium AD by Austronesian settlers from the Greater Sunda Islands.
KUM has conducted excavations, that have revealed similarly dated paddy field features, at Yaeum-dong and Okhyeon, in modern-day Ulsan.
[26] The earliest Mumun features were usually located in low-lying narrow gullies, that were naturally swampy and fed by the local stream system.
[27][28] Mumun Period rice farmers used all of the elements that are present in today's paddy fields, such as terracing, bunds, canals, and small reservoirs.
We can grasp some paddy-field farming techniques of the Middle Mumun (c. 850–550 BC), from the well-preserved wooden tools excavated from archaeological rice fields at the Majeon-ni Site.
Most rice is grown south of the Huai River, in the Yangtze valley, the Zhu Jiang delta, and in Yunnan, Guizhou, and Sichuan provinces.
[33] Bruce Smith, an archaeologist at the Smithsonian Institution in Washington, D.C., who has written on the origins of agriculture, says that evidence has been mounting that the Yangtze was probably the site of the earliest rice cultivation.
One was the use of cast iron tools and beasts of burden to pull plows, and the other was the large-scale harnessing of rivers and development of water conservation projects.
During the Eastern Jin (317–420) and the Northern and Southern Dynasties (420–589), land-use became more intensive and efficient, rice was grown twice a year and cattle began to be used for plowing and fertilization.
Steep terrain on Bali resulted in complex irrigation systems, locally called subak, to manage water storage and drainage for rice terraces.
[citation needed] The acidic soil conditions common in Japan due to volcanic eruptions have made the paddy field the most productive farming method.
Paddy fields are represented by the kanji 田 (commonly read as ta or as den) that has had a strong influence on Japanese culture.
One of the oldest samples of writing in Japan is widely credited to the kanji 田 found on pottery at the archaeological site of Matsutaka in Mie Prefecture that dates to the late 2nd century.
[40] Arable land in small alluvial flats of most rural river valleys in South Korea are dedicated to paddy-field farming.
Criticized as being the cause of deforestation, tavy is still widely practiced by farmers in Madagascar, who find a good compromise between climate risks, availability of labour and food security.
By extension, the tanety, which literally means "hill," is also growing upland rice, carried out on the grassy slopes that have been deforested for the production of charcoal (139,337 ha).
[48] Rice fields in Vietnam (ruộng or cánh đồng in Vietnamese) are the predominant land use in the valley of the Red River and the Mekong Delta.
In Northwestern Vietnam, Thai people built their "valley culture" based on the cultivation of glutinous rice planted in upland fields, requiring terracing of the slopes.
The primary festival related to the agrarian cycle is "lễ hạ điền" (literally "descent into the fields") held as the start of the planting season in hope of a bountiful harvest.
Paddy fields so large as for "storks to fly with their wings out-stretched" ("đồng lúa thẳng cánh cò bay") can be heard as a common metaphor.
[50][51] Studies have shown that this can be significantly reduced while also boosting crop yield by draining the paddies to allow the soil to aerate to interrupt methane production.
[52] Studies have also shown the variability in assessment of methane emission using local, regional and global factors and calling for better inventorization based on micro level data.