Recent from talks
Nothing was collected or created yet.
Paddy field
View on Wikipedia




A paddy field (or paddy) is a flooded field of arable land used for growing semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in southern China, associated with pre-Austronesian and Hmong-Mien cultures. It was spread in prehistoric times by the expansion of Austronesian peoples to Island Southeast Asia, Madagascar, Melanesia, Micronesia, and Polynesia. The technology was also acquired by other cultures in mainland Asia for rice farming, spreading to East Asia, Mainland Southeast Asia, and South Asia.
Fields can be built into steep hillsides as terraces or adjacent to depressed or steeply sloped features such as rivers or marshes. They require a great deal of labor and materials to create and need large quantities of water for irrigation. Oxen and water buffalo, adapted for life in wetlands, are important working animals used extensively in paddy field farming.
Paddy field farming remains the dominant form of growing rice in modern times. It is practiced extensively in Bangladesh, Cambodia, China, India, Indonesia, northern Iran, Japan, Laos, Malaysia, Mongolia, Myanmar, Nepal, North Korea, Pakistan, the Philippines, South Korea, Sri Lanka, Taiwan, Thailand, and Vietnam.[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.[citation needed]
Paddy cultivation should not be confused with cultivation of deepwater rice, which is grown in flooded conditions with water more than 50 cm (20 in) deep for at least a month. Global paddies' emissions account for at least 10% of global methane emissions. Drip irrigation systems have been proposed as a possible environmental and commercial solution.
Etymology
[edit]The word "paddy" is derived from the Malay/Indonesian word padi, meaning "rice plant",[3] which is itself derived from Proto-Austronesian *pajay ("rice in the field", "rice plant"). Cognates include Amis panay; Tagalog pálay; Kadazan Dusun paai; Javanese pari; and Chamorro faʻi, among others.[4] In the original Malay language that English borrows, padi refers to both the rice plant and its unhusked grains, the fields are instead called sawah.[5]
History
[edit]Neolithic southern China
[edit]
(8500 to 1500 BC)
Genetic evidence shows that all forms of paddy rice, including both indica and japonica, spring from a domestication of the wild rice Oryza rufipogon by cultures associated with pre-Austronesian and Hmong-Mien-speakers. This occurred 13,500 to 8,200 years ago south of the Yangtze River in present-day China.[6][7]

There are two likely centers of domestication for rice as well as the development of the wet-field technology. 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.[8][9][10][11][12] 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. Both of these regions were heavily populated and had regular trade contacts with each other, as well as with early Austroasiatic speakers to the west, and early Kra-Dai speakers to the south, facilitating the spread of rice cultivation throughout southern China.[9][10][12]

The earliest paddy field found dates to 4330 BC, based on carbon dating of grains of rice and soil organic matter found at the Chaodun site in Kunshan.[13][14] At Caoxieshan, a site of the Neolithic Majiabang culture, archaeologists excavated paddy fields.[15] Some archaeologists claim that Caoxieshan may date to 4000–3000 BC.[16][17] There is archaeological evidence that unhusked rice was stored for the military and for burial with the deceased from the Neolithic period to the Han dynasty in China.[18]
By the late Neolithic (3500 to 2500 BC), population in the rice cultivating centers had increased rapidly, centered around the Qujialing-Shijiahe and Liangzhu cultures. There was also evidence of intensive rice cultivation in paddy fields as well as increasingly sophisticated material cultures in these two regions. 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. However, it is unknown if they had centralized control.[19][20]
In the terminal Neolithic (2500 to 2000 BC), Shijiahe shrank in size, and Liangzhu disappeared altogether. This is largely believed to be the result of the southward expansion of the early Sino-Tibetan Longshan culture. Fortifications like walls (as well as extensive moats in Liangzhu cities) are common features in settlements during this period, indicating widespread conflict. This period also coincides with the southward movement of rice-farming cultures to the Lingnan and Fujian regions, as well as the southward migrations of the Austronesian, Kra-Dai, and Austroasiatic-speaking peoples to Mainland Southeast Asia and Island Southeast Asia.[19][21][22]
Austronesian expansion
[edit]
(3500 BC to AD 1200)

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. The Nanguanli site in Taiwan, dated to ca. 2800 BC, has yielded numerous carbonized remains of both rice and millet in waterlogged conditions, indicating intensive wetland rice cultivation and dryland millet cultivation.[10]

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. By 500 BC, there is evidence of intensive wetland rice agriculture already established in Java and Bali, especially near very fertile volcanic islands.[10]
Rice did not survive the Austronesian voyages into Micronesia and Polynesia; however, wet-field agriculture was transferred to the cultivation of other crops, most notably for taro cultivation. 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. In turn, they assimilated their range of indigenous cultivated fruits and tubers before spreading further eastward to Island Melanesia and Polynesia.[10] In Hawaii, the conditions of available taro pondfields (loʻi) as worked by native Hawaiians later proved feasible for rice cultivation by Chinese and Japanese migrant farmers in the late 19th to early 20th century; rice plots were often enlarged by dismantling bunds (kuāuna) that bordered between smaller established loʻi.[23]
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.[24]
Korea
[edit]There are ten archaeologically excavated rice paddy fields in Korea. The two oldest are the Okhyun and Yaumdong sites, found in Ulsan, dating to the early Mumun pottery period.[25]
Paddy field farming goes back thousands of years in Korea. A pit-house at the Daecheon-ni site yielded carbonized rice grains and radiocarbon dates, indicating that rice cultivation in dry-fields may have begun as early as the Middle Jeulmun pottery period (c. 3500–2000 BC) in the Korean Peninsula.[26] Ancient paddy fields have been carefully unearthed in Korea by institutes such as Kyungnam University Museum (KUM) of Masan. They excavated paddy field features at the Geumcheon-ni Site near Miryang, South Gyeongsang Province. The paddy field feature was found next to a pit-house that is dated to the latter part of the Early Mumun pottery period (c. 1100–850 BC). KUM has conducted excavations, that have revealed similarly dated paddy field features, at Yaeum-dong and Okhyeon, in modern-day Ulsan.[27]
The earliest Mumun features were usually located in low-lying narrow gullies, that were naturally swampy and fed by the local stream system. Some Mumun paddy fields in flat areas were made of a series of squares and rectangles, separated by bunds approximately 10 cm in height, while terraced paddy fields consisted of long irregular shapes that followed natural contours of the land at various levels.[28][29]
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. However, iron tools for paddy-field farming were not introduced until sometime after 200 BC. The spatial scale of paddy-fields increased, with the regular use of iron tools, in the Three Kingdoms of Korea Period (c. AD 300/400-668).[citation needed]
Japan
[edit]The first paddy fields in Japan date to the Early Yayoi period (300 BC – 250 AD).[30] The Early Yayoi has been re-dated,[31] and based on studies of early Japanese paddy formations in Kyushu it appears that wet-field rice agriculture in Japan was directly adopted from the Lower Yangtze river basin in Eastern China.[citation needed]
Culture
[edit]| China | 208.1 |
| India | 206.7 |
| Bangladesh | 58.6 |
| Indonesia | 54.0 |
| Vietnam | 43.5 |
| Thailand | 33.1 |
| Myanmar | 25.7 |
| Philippines | 20.1 |
| Pakistan | 14.8 |
| Cambodia | 12.9 |
| Brazil | 10.3 |
| Japan | 10.1 |
| United States | 9.9 |
| Nigeria | 8.9 |
| Nepal | 5.7 |
| Egypt | 5.6 |
| Madagascar | 5.1 |
| South Korea | 4.9 |
| Sri Lanka | 4.5 |
| Laos | 3.8 |
| Source: Food and Agriculture Organization | |
China
[edit]
Although China's agricultural output is the largest in the world, only about 15% of its total land area can be cultivated. About 75% of the cultivated area is used for food crops. Rice is China's most important crop, raised on about 25% of the cultivated area. Most rice is grown south of the Huai River, in the Yangtze valley, the Zhu Jiang delta, and in Yunnan, Guizhou, and Sichuan provinces.[citation needed]
Rice appears to have been used by the Early Neolithic populations of Lijiacun and Yunchanyan in China.[33] Evidence of possible rice cultivation from ca. 11,500 BC has been found, however it is still questioned whether the rice was indeed being cultivated, or instead being gathered as wild rice.[34] 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.[35] In 1998, Crawford & Shen reported that the earliest of 14 AMS or radiocarbon dates on rice from at least nine Early to Middle Neolithic sites is no older than 7000 BC, that rice from the Hemudu and Luojiajiao sites indicates that rice domestication likely began before 5000 BC, but that most sites in China from which rice remains have been recovered are younger than 5000 BC.[33]

During the Spring and Autumn period (722–481 BC), two revolutionary improvements in farming technology took place. 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. Sunshu Ao of the 6th century BC and Ximen Bao of the 5th century BC are two of the earliest hydraulic engineers from China, and their works were focused upon improving irrigation systems.[36] These developments were widely spread during the ensuing Warring States period (403–221 BC), culminating in the enormous Du Jiang Yan Irrigation System engineered by Li Bing by 256 BC for the State of Qin in ancient Sichuan. 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.
By about 750, 75% of China's population lived north of the Yangtze, but by 1250, 75% of China's population lived south of it. Such large-scale internal migration was possible due to introduction of quick-ripening strains of rice from Vietnam suitable for multi-cropping.[37]
Famous rice paddies in China include the Longsheng Rice Terraces and the fields of Yuanyang County, Yunnan.[citation needed]
India
[edit]
India has the largest paddy output in the world and is also the largest exporter of rice in the world as of 2020. In India, West Bengal is the largest rice producing state.[38] Paddy fields are a common sight throughout India, both in the northern Gangetic Plains and the southern peninsular plateaus. Paddy is cultivated at least twice a year in most parts of India, the two seasons being known as Rabi and Kharif respectively. The former cultivation is dependent on irrigation, while the latter depends on the Monsoon. The paddy cultivation plays a major role in socio-cultural life of rural India. Many regional festivals celebrate the harvest, such as Onam, Bihu, Thai Pongal, Makar Sankranti, and Nabanna. The Kaveri delta region of Thanjavur is historically known as the rice bowl of Tamil Nadu, and Kuttanadu is called the rice bowl of Kerala. Gangavathi is known as the rice bowl of Karnataka.[citation needed]
Indonesia
[edit]
In the island of Java, prime paddies yield roughly 6 metric tons of unmilled rice (2.5 metric tons of milled rice) per hectare. When irrigation is available, rice farmers typically plant Green Revolution rice varieties allowing three growing seasons per year. Since fertilizer and pesticide are relatively expensive inputs, farmers typically plant seeds in a very small plot. Three weeks following germination, the 15-20 centimetre (6–8 in) stalks are picked and replanted at greater separation, in a backbreaking manual procedure.
Rice harvesting in Central Java is often performed not by owners or sharecroppers of paddies, but rather by itinerant middlemen, whose small firms specialize in the harvest, transport, milling, and distribution of rice.
The fertile volcanic soil of much of the Indonesian archipelago—particularly the islands of Java and Bali—has made rice a central dietary staple. Steep terrain on Bali resulted in complex irrigation systems, locally called subak, to manage water storage and drainage for rice terraces.[39]
Italy
[edit]
Rice is grown in Northern Italy, especially in the valley of the Po River.[40] The paddy fields are irrigated by fast-flowing streams descending from the Alps. In the 19th century and much of the 20th century, the paddy fields were farmed by the mondine, a subculture of seasonal rice paddy workers composed mostly of poor women.[citation needed]
Japan
[edit]
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. In fact, the character 田, which originally meant 'field' in general, is used in Japan exclusively to refer to paddy fields. 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.
Ta (田) is used as a part of many place names as well as in many family names. Most of these places are somehow related to the paddy field and, in many cases, are based on the history of a particular location. For example, where a river runs through a village, the place east of the river may be called Higashida (東田), literally "east paddy field." A place with a newly irrigated paddy field, especially those made during or after the Edo period, may be called Nitta or Shinden (both 新田), "new paddy field." In some places, lakes and marshes were likened to a paddy field and were named with ta, like Hakkōda (八甲田).
Today, many family names have ta as a component, a practice which can be largely attributed to a government edict in the early Meiji Period which required all citizens to have a family name. Many chose a name based on some geographical feature associated with their residence or occupation, and as nearly three-fourths of the population were farmers, many made family names using ta. Some common examples are Tanaka (田中), literally meaning "in the paddy field;" Nakata (中田), "middle paddy field;" Kawada (川田), "river paddy field;" and Furuta (古田), "old paddy field."[citation needed]
In recent years, rice consumption in Japan has fallen and many rice farmers are increasingly elderly. The government has subsidized rice production since the 1970s, and favors protectionist policies regarding cheaper imported rice.[41]
Korea
[edit]
Arable land in small alluvial flats of most rural river valleys in South Korea are dedicated to paddy-field farming. Farmers assess paddy fields for any necessary repairs in February. Fields may be rebuilt, and bund breaches are repaired. This work is carried out until mid-March, when warmer spring weather allows the farmer to buy or grow rice seedlings. They are transplanted (usually by rice transplanter) from the indoors into freshly flooded paddy fields in May. Farmers tend and weed their paddy fields through the summer until around the time of Chuseok, a traditional holiday held on 15 August of the Lunar Calendar (circa mid-September on the Solar Calendar). The harvest begins in October. Coordinating the harvest can be challenging because many Korean farmers have small paddy fields in a number of locations around their villages, and modern harvesting machines are sometimes shared between extended family members. Farmers usually dry the harvested grains in the sun before bringing them to market.[citation needed]
The Hanja character for 'field', jeon (Korean: 전; Hanja: 田), is found in some place names, especially small farming townships and villages. However, the specific Korean term for 'paddy' is a purely Korean word, "non" (Korean: 논).[citation needed]
Madagascar
[edit]
In Madagascar, the average annual consumption of rice is 130 kg per person, one of the largest in the world.
According to a 1999 study of UPDRS / FAO:
The majority of rice is related to irrigation (1,054,381 ha). The choice of methods conditioning performance is determined by the variety and quality control of water.
The tavy is traditionally the culture of flooded upland rice on burning of cleared natural rain forest (135,966 ha). 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).
Among the many varieties, rice of Madagascar includes: Vary lava - a translucent long and large grain rice, considered a luxury rice; Vary Makalioka - a translucent long and thin grain rice; Vary Rojofotsy - a half-long grain rice; and Vary mena, or red rice, exclusive to Madagascar.[citation needed]
Malaysia
[edit]
Paddy fields can be found in most states on the Malay Peninsula, with most of the fields being located in the northern states such as Kedah, Perlis, Perak, and Penang. Paddy fields can also be found on the east coast region including states of Kelantan and Terengganu, their growth relies on seasonal rainfall[42] from the northeast monsoon winds of the South China Sea. The state of Selangor on further south also has its fair share of paddy fields, especially in the districts of Kuala Selangor and Sabak Bernam.[citation needed]
Before the regions that formed Malaysia became heavily reliant on its industrial output, people were mainly involved in agriculture, especially in the production of rice. It was for that reason, that people usually built their houses next to paddy fields.[citation needed] Some research pertaining to Rainfed lowland rice in Sarawak has been reported.[1]
Myanmar
[edit]Rice is grown in Myanmar primarily in three areas – the Irrawaddy Delta, the area along and the delta of the Kaladan River, and the Central plains around Mandalay, though there has been an increase in rice farming in Shan State and Kachin State in recent years.[43] Up until the later 1960s, Myanmar was the main exporter of rice. Termed the rice basket of Southeast Asia, much of the rice grown in Myanmar does not rely on fertilizers and pesticides, thus, although "organic" in a sense, it has been unable to cope with population growth and other rice economies which utilized fertilizers.
Rice is now grown in all the three seasons of Myanmar, though primarily in the Monsoon season – from June to October. Rice grown in the delta areas relies heavily on the river water and sedimented minerals from the northern mountains, whilst the rice grown in the central regions require irrigation from the Irrawaddy River.
The fields are tilled when the first rains arrive – traditionally measured at 40 days after Thingyan, the Burmese New Year – around the beginning of June. In modern times, tractors are used, but traditionally, buffalos were employed. The rice plants are planted in nurseries and then transplanted by hand into the prepared fields. The rice is then harvested in late November – "when the rice bends with age". Most of the rice planting and harvesting is done by hand. The rice is then threshed and stored, ready for the mills.[citation needed]
Nepal
[edit]In Nepal, rice (Nepali: धान, Dhaan) is grown in the Terai and hilly regions. It is mainly grown during the summer monsoon in Nepal.[44]
Philippines
[edit]
Paddy fields are a common sight in the Philippines. Several vast paddy fields exist in the provinces of Ifugao, Nueva Ecija, Isabela, Cagayan, Bulacan, Quezon, and other provinces. Nueva Ecija is considered the main rice growing province of the Philippines.[citation needed]
The Banaue Rice Terraces are an example of paddy fields in the country. They are located in Banaue in Northern Luzon, Philippines and were built by the Ifugaos 2,000 years ago.[45] Streams and springs found in the mountains were tapped and channeled into irrigation canals that run downhill through the rice terraces. Other notable Philippine paddy fields are the Batad Rice Terraces, the Bangaan Rice Terraces, the Mayoyao Rice Terraces and the Hapao Rice Terraces.[46]
Located at Barangay Batad in Banaue, the Batad Rice Terraces are shaped like an amphitheatre, and can be reached by a 12-kilometer ride from Banaue Hotel and a 2-hour hike uphill through mountain trails. The Bangaan Rice Terraces portray the typical Ifugao community, where the livelihood activities are within the village and its surroundings. The Bangaan Rice Terraces are accessible by a one-hour ride from Poblacion, Banaue, then a 20-minute trek down to the village. It can be viewed best from the road to Mayoyao. The Mayoyao Rice Terraces are located at Mayoyao, 44 kilometers away from Poblacion, Banaue. The town of Mayoyao lies in the midst of these rice terraces. All dikes are tiered with flat stones. The Hapao Rice Terraces are within 55 kilometers from the capital town of Lagawe. Other Ifugao stone-walled rice terraces are located in the municipality of Hungduan.[46]
Sri Lanka
[edit]Sri Lankan paddy cultivation history dates back to more than 2000 years ago. The historical reports say that Sri Lanka is regarded as the "paddy store of the east" because it produced an excessive quantity of rice. Paddy cultivation can be found all over the island and a considerable amount of land is allocated for it. Both upcountry and low country wetlands use paddy cultivation. The majority of paddy land is in the dry zone, and it uses special irrigation systems for cultivation. The water storing tank called "Wewa" facilitates a supply of water to paddy lands in the cultivation period. Agriculture in Sri Lanka mainly depends on rice production.[47] Sri Lanka sometimes exports rice to its neighboring countries. Around 1.5 million hectares of land are cultivated in Sri Lanka for paddy in 2008/2009 maha: 64% of which is cultivated during the dry season and 35% cultivated during the wet season. Around 879,000 farmer families are engaged in paddy cultivation in Sri Lanka. They make up 20% of the country's population and 32% of the employment.[citation needed]
Thailand
[edit]
Rice production in Thailand represents a significant portion of the Thai economy. It uses over half of the farmable land area and labor force in Thailand.[48]
Thailand has a strong tradition of rice production. It has the fifth-largest amount of land used for rice cultivation in the world and is the world's largest exporter of rice.[49] Thailand has plans to further increase its land available for rice production, with a goal of adding 500,000 hectares to the 9.2 million hectares of rice-growing areas already cultivated.[50] The Thai Ministry of Agriculture expected rice production to yield around 30 million tons of rice for 2008.[51] The most produced strain of rice in Thailand is jasmine rice, which has a significantly lower yield rate than other types of rice, but also normally fetches more than double the price of other strains in a global market.[50]
Vietnam
[edit]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 the Red River Delta of northern Vietnam, control of seasonal river flooding is achieved by an extensive network of dykes which over the centuries total some 3000 km. In the Mekong Delta of southern Vietnam, there is an interlacing drainage and irrigation canal system that has become the symbol of this area. The canals additionally serve as transportation routes, allowing farmers to bring their produce to market. 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. Traditionally, the event was officiated with much pomp. The monarch carried out the ritual plowing of the first furrow while local dignitaries and farmers followed suit. Thổ địa (deities of the earth), thành hoàng làng (the village patron spirit), Thần Nông (god of agriculture), and thần lúa (god of rice plants) were all venerated with prayers and offerings.
In colloquial Vietnamese, wealth is frequently associated with the vastness of the individual's land holdings. 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. Wind-blown undulating rice plants across a paddy field in literary Vietnamese is termed figuratively "waves of rice plants" ("sóng lúa").[citation needed]
Ecology
[edit]Paddy fields are a major source of atmospheric methane which contributes to global warming, having been estimated to contribute in the range of 50 to 100 million tonnes of the gas per annum.[52][53] 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.[54] 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.[55]
Rice paddies are responsible for 10% of global methane emissions, roughly equal to the emissions of the aviation industry.[56] Drip irrigation systems developed by Netafim and N-Drip were introduced in several countries and according to The Times of Israel can reduce up to 85% of emissions.[57]
Gallery
[edit]See also
[edit]- Kuk Swamp
- Rice-fish system
- Upland rice – Rice grown in dry fields
References
[edit]- ^ a b Sang, Anisia Jati; Tay, Kai Meng; Lim, Chee Peng; Saeid, Nahavandi (2018). "Application of a Genetic-Fuzzy FMEA to Rainfed Lowland Rice Production in Sarawak: Environmental, Health, and Safety Perspectives". IEEE Access. 6: 74628–74647. Bibcode:2018IEEEA...674628S. doi:10.1109/ACCESS.2018.2883115. hdl:10536/DRO/DU:30118456.
- ^ "Riz de Camargue, Silo de Tourtoulen, Riz blanc de Camargue, Riz et céréales de Camargue". Riz-camargue.com. Archived from the original on 14 May 2013. Retrieved 25 April 2013.
- ^ "paddy". Merriam Webster. Retrieved 15 July 2007.
- ^ Blust, Robert; Trussel, Stephen. "*pajay — rice in the field; rice plant". Austronesian Comparative Dictionary. Retrieved 29 June 2019.
- ^ Elson, R. E. (2016). The End of the Peasantry in Southeast Asia: A Social and Economic History of Peasant Livelihood, 1800-1990s. Springer. p. xiv. ISBN 978-1-349-25457-6.
- ^ Molina, J.; Sikora, M.; Garud, N.; Flowers, J. M.; Rubinstein, S.; Reynolds, A.; Huang, P.; Jackson, S.; Schaal, B. A.; Bustamante, C. D.; Boyko, A. R.; Purugganan, M. D. (2011). "Molecular evidence for a single evolutionary origin of domesticated rice". Proceedings of the National Academy of Sciences. 108 (20): 8351–6. Bibcode:2011PNAS..108.8351M. doi:10.1073/pnas.1104686108. PMC 3101000. PMID 21536870.
- ^ Gross, B. L.; Zhao, Z. (2014). "Archaeological and genetic insights into the origins of domesticated rice". Proceedings of the National Academy of Sciences. 111 (17): 6190–7. Bibcode:2014PNAS..111.6190G. doi:10.1073/pnas.1308942110. PMC 4035933. PMID 24753573.
- ^ Zhang, Jianping; Lu, Houyuan; Gu, Wanfa; Wu, Naiqin; Zhou, Kunshu; Hu, Yayi; Xin, Yingjun; Wang, Can; Kashkush, Khalil (17 December 2012). "Early Mixed Farming of Millet and Rice 7800 Years Ago in the Middle Yellow River Region, China". PLOS ONE. 7 (12) e52146. Bibcode:2012PLoSO...752146Z. doi:10.1371/journal.pone.0052146. PMC 3524165. PMID 23284907.
- ^ a b c He, Keyang; Lu, Houyuan; Zhang, Jianping; Wang, Can; Huan, Xiujia (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China". The Holocene. 27 (12): 1885–1898. Bibcode:2017Holoc..27.1885H. doi:10.1177/0959683617708455. S2CID 133660098.
- ^ a b c d e f Bellwood, Peter (9 December 2011). "The Checkered Prehistory of Rice Movement Southwards as a Domesticated Cereal—from the Yangzi to the Equator" (PDF). Rice. 4 (3–4): 93–103. Bibcode:2011Rice....4...93B. doi:10.1007/s12284-011-9068-9. S2CID 44675525.
- ^ Hsieh, Jaw-shu; Hsing, Yue-ie Caroline; Hsu, Tze-fu; Li, Paul Jen-kuei; Li, Kuang-ti; Tsang, Cheng-hwa (24 December 2011). "Studies on Ancient Rice—Where Botanists, Agronomists, Archeologists, Linguists, and Ethnologists Meet". Rice. 4 (3–4): 178–183. Bibcode:2011Rice....4..178H. doi:10.1007/s12284-011-9075-x.
- ^ a b Li, Hui; Huang, Ying; Mustavich, Laura F.; Zhang, Fan; Tan, Jing-Ze; Wang, ling-E; Qian, Ji; Gao, Meng-He; Jin, Li (2007). "Y chromosomes of prehistoric people along the Yangtze River" (PDF). Human Genetics. 122 (3–4): 383–388. doi:10.1007/s00439-007-0407-2. PMID 17657509. S2CID 2533393. Archived from the original (PDF) on 14 December 2013.
- ^ Cao, Zhihong; Fu, Jianrong; Zou, Ping; Huang, Jing Fa; Lu, Hong; Weng, Jieping; Ding, Jinlong (August 2010). "Origin and chronosequence of paddy soils in China". Proceedings of the 19th World Congress of Soil Science: 39–42. Retrieved 8 February 2013.
- ^ Bellwood, Peter (1997). "Prehistory of the Indo-Malaysian Archipelago". Prehistory of the Indo-Malaysian Archipelago: Revised Edition. Honolulu: University of Hawaiʻi Press. pp. 205–211. ISBN 0-8248-1883-0. JSTOR j.ctt24hf81.
- ^ Fujiwara, H. (ed.). Search for the Origin of Rice Cultivation: The Ancient Rice Cultivation in Paddy Fields at the Cao Xie Shan Site in China. Miyazaki: Society for Scientific Studies on Cultural Property, 1996. (In Japanese and Chinese)
- ^ Fujiwara 1996
- ^ Tsude, Hiroshi. Yayoi Farmers Reconsidered: New Perspectives on Agricultural Development in East Asia. Bulletin of the Indo-Pacific Prehistory Association 21(5):53–59, 2001.
- ^ "Expansion of Chinese Paddy Rice to the Yunnan-Guizhou Plateau". Archived from the original on 27 September 2007. Retrieved 6 August 2007.
- ^ a b Zhang, Chi; Hung, Hsiao-Chun (2008). "The Neolithic of Southern China – Origin, Development, and Dispersal" (PDF). Asian Perspectives. 47 (2).
- ^ Zhang, Chi (2013). "The Qujialing–Shijiahe culture in the middle Yangzi River valley". In Underhill, Anne P. (ed.). A Companion to Chinese Archaeology. John Wiley & Sons. pp. 510–534. ISBN 978-1-118-32578-0.
- ^ Liu, Li; Chen, Xingcan (2012). The Archaeology of China: From the Late Paleolithic to the Early Bronze Age. Cambridge University Press. ISBN 978-0-521-64310-8.
- ^ Major, John S.; Cook, Constance A. (2016). Ancient China: A History. Taylor & Francis. ISBN 978-1-317-50366-8.
- ^ Jones, Benjamin D.; Ladefoged, Thegn N.; Asner, Gregory (March 2015). "Tracing the resilience and revitalisation of historic taro production in Waipi'o Valley, Hawaiʻi". Journal of the Polynesian Society. 124 (1): 99–100. doi:10.15286/jps.124.1.83-109.
- ^ Beaujard, Philippe (August 2011). "The first migrants to Madagascar and their introduction of plants: linguistic and ethnological evidence" (PDF). Azania: Archaeological Research in Africa. 46 (2): 169–189. doi:10.1080/0067270X.2011.580142. S2CID 55763047.
- ^ Crawford, Gary W. and Gyoung-Ah Lee. Agricultural Origins in the Korean Peninsula. Antiquity 77(295):87–95, 2003.
- ^ Crawford and Lee 2003
- ^ Bale, Martin T. Archaeology of Early Agriculture in Korea: An Update on Recent Developments. Bulletin of the Indo-Pacific Prehistory Association 21(5):77–84, 2001.
- ^ Bale 2001
- ^ Kwak, Jong-chul. Urinara-eui Seonsa – Godae Non Bat Yugu [Dry- and Wet-field Agricultural Features of the Korean Prehistoric].In Hanguk Nonggyeong Munhwa-eui Hyeongseong [The Formation of Agrarian Societies in Korea]: 21–73. Papers of the 25th National Meetings of the Korean Archaeological Society, Busan, 2001
- ^ Barnes, Gina L. Paddy Soils Now and Then. World Archaeology 22(1):1–17, 1990.
- ^ Shōda, Shinya (2007). "A Comment on the Yayoi Period Dating Controversy". Bulletin of the Society for East Asian Archaeology. 1. Archived from the original on 1 August 2019. Retrieved 9 March 2021.
- ^ "Countries by commodity (Rice)". FAOSTAT. Retrieved 14 August 2025.
- ^ a b Crawford and Shen 1998
- ^ Harrington, Spencer P.M. (11 June 1997). "Earliest Rice". Archaeology. Archaeological Institute of America.
Rice cultivation began in China ca. 11,500 years ago, some 3,500 years earlier than previously believed
- ^ Normile, Dennis (1997). "Yangtze seen as earliest rice site". Science. 275 (5298): 309–310. doi:10.1126/science.275.5298.309. S2CID 140691699.
- ^ Needham, Joseph (1986). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 3, Civil Engineering and Nautics. Taipei: Caves Books Ltd. Page 271.
- ^ Angus, Maddison (21 September 2006). The World Economy, Angus Maddison, p.20, ISBN 92-64-02261-9. OECD. ISBN 978-92-64-02261-4. Retrieved 25 April 2013.
- ^ "Top 10 Rice Producing States of India, Indian States with Highest Rice Production". Mapsofindia.com. 17 January 2012. Retrieved 25 April 2013.
- ^ "Lansing and Miller" (PDF). Archived from the original (PDF) on 27 March 2009. Retrieved 25 April 2013.
- ^ "Channel 4 notes for schools". Channel4.com. Retrieved 25 April 2013.
- ^ "Economist.com". The Economist. 17 December 2009. Retrieved 25 April 2013.
- ^ Elson 2016, p. 92.
- ^ "Increasing rice production in Myanmar". Archived from the original on 25 September 2015. Retrieved 4 May 2015.
- ^ "New Agriculturist: Country profile - Nepal". www.new-ag.info.
- ^ UNESCO World Heritage Centre. "Rice Terraces of the Philippine Cordilleras – UNESCO World Heritage Centre". Whc.unesco.org. Retrieved 5 May 2015.
- ^ a b "Error". Retrieved 1 April 2011.
- ^ "Rice Knowledge for Sri Lanka - IRRI Rice Knowledge Bank". www.knowledgebank.irri.org.
- ^ Country Profile: Thailand. lcweb2.loc.gov 7 (July 2007).
- ^ Thailand backs away from rice cartel plan." The International Herald Tribune 7 May 2008: 12. 2 February 2009, lexisnexis.com
- ^ a b "Rice strain is cause of comparatively low productivity." The Nation (Thailand) 16 April 2008. 2 February 2009, lexisnexis.com
- ^ Nirmal, Ghost. "Thailand to set aside more land for farming; It plans to increase rice production and stop conversion of agricultural land." The Straits Times (Singapore) 24 April 2008.
- ^ "Methane Sources – Rice Paddies". Retrieved 15 July 2007.
- ^ "Scientists blame global warming on rice". Sptimes.com. 2 May 2007. Retrieved 25 April 2013.
- ^ "Shifts in rice farming practices in China reduce greenhouse gas methane". Goddard Space Flight Center. Archived from the original on 11 January 2003. Retrieved 19 December 2002.
- ^ Mishra S. N., Mitra S., Rangan L, Dutta S., and Pooja. (2012). Exploration of 'hot-spots' of methane and nitrous oxide emission from the agriculture fields of Assam, India. Agriculture and Food Security. 1/16. doi:10.1186/2048-7010-1-16.
- ^ Surkes, Sue (10 May 2021). "Israel's drip irrigation pioneers aim to do away with flooded rice fields".
- ^ Wrobel, Sharon (21 June 2023). "Agritech firm N-Drip raises $44 million in Liechtenstein-led funding round". Times of Israel.
Bibliography
[edit]- Bale, Martin T. Archaeology of Early Agriculture in Korea: An Update on Recent Developments. Bulletin of the Indo-Pacific Prehistory Association 21(5):77–84, 2001.
- Barnes, Gina L. Paddy Soils Now and Then. World Archaeology 22(1):1–17, 1990.
- Crawford, Gary W. and Gyoung-Ah Lee. Agricultural Origins in the Korean Peninsula. Antiquity 77(295):87–95, 2003.
- Kwak, Jong-chul. Urinara-eui Seonsa – Godae Non Bat Yugu [Dry- and Wet-field Agricultural Features of the Korean Prehistoric].In Hanguk Nonggyeong Munhwa-eui Hyeongseong [The Formation of Agrarian Societies in Korea]: 21–73. Papers of the 25th National Meetings of the Korean Archaeological Society, Busan, 2001.
External links
[edit]Paddy field
View on GrokipediaA paddy field is a flooded parcel of arable land, typically enclosed by earthen bunds, used primarily for cultivating semiaquatic crops such as rice (Oryza sativa), where shallow standing water is maintained during the growing season to suppress weeds, facilitate nutrient uptake, and mimic the plant's natural wetland habitat.[1][2] This method of wetland agriculture originated in East Asia, with archaeological evidence of organized paddy fields dating to around 4000 BC in China's lower Yangtze River valley, marking the transition from dryland millet farming to intensive irrigated rice production that supported population growth and societal complexity.[3] Paddy fields remain central to global rice output, which exceeds 700 million metric tons annually and sustains over half the world's population as a dietary staple, though they also contribute significantly to anthropogenic methane emissions due to anaerobic conditions in flooded soils.[4][5] Cultivation typically involves preparing bunded fields, sowing seeds in nurseries or directly, transplanting seedlings into flooded plots, and managing water levels through irrigation systems, with variations like terracing in upland areas to expand cultivable land on slopes.[6][7] While predominantly associated with Asia—where China and India produce over half of the world's paddy rice—these fields have spread globally via historical migrations and trade, influencing landscapes, economies, and cultures from ancient river valleys to modern export-oriented farms.[8]
Definition and Terminology
Etymology
The English term "paddy" derives from the Malay word padi, signifying the rice plant or unmilled rice in the husk.[9][10] This borrowing occurred during early European contact with Southeast Asian trade routes, with the first recorded English usage appearing around 1623 to denote unmilled rice.[11] The word padi itself traces to Proto-Austronesian roots associated with rice cultivation, reflecting the crop's central role in Austronesian-speaking societies.[9] In agricultural contexts, "paddy" extended to describe the flooded fields optimized for Oryza sativa (Asian rice) under wet cultivation, distinguishing them from dryland systems.[9] The compound "paddy field" emerged in the mid-18th century, with its earliest documented instance in 1763, coinciding with growing European interest in Asian rice farming techniques.[12] This terminology underscores the method's reliance on seasonal inundation for weed suppression and nutrient retention, a practice integral to intensive rice production in monsoon-dependent regions. Regional variants, such as the Tagalog palay (a doublet of padi), highlight parallel linguistic evolutions in rice-centric cultures.[13]Physical and functional characteristics
Paddy fields consist of leveled land plots bounded by earthen embankments known as bunds, which retain shallow standing water for rice production. These bunds, constructed from compacted soil, typically rise 20-50 cm above the field level to minimize seepage and enable subdivision of larger areas into individual units of varying sizes, often 0.1 to 1 hectare depending on local topography and farming practices. The soil surface is puddled—plowed and flooded to create a compact, impermeable layer—that reduces water percolation and maintains saturation. In undulating terrains, fields are terraced, with bunds doubling as retaining walls to stabilize slopes and channel water downslope across multiple levels.[14][15] Functionally, paddy fields operate as managed wetlands where continuous flooding, usually 5-10 cm deep during vegetative and reproductive stages, induces anaerobic conditions in the soil. Rice plants, adapted via aerenchyma tissue that transports oxygen from shoots to roots, tolerate these low-oxygen environments, whereas many competing weeds and pathogens struggle, achieving effective natural suppression without heavy reliance on herbicides. This water regime also enhances nutrient dynamics by promoting reductive processes that solubilize bound phosphorus and iron, increasing availability to rice roots, while the overlying water buffers against extreme temperatures and cuts evaporative losses relative to dryland cropping.[16][17][17] Towards maturity, fields are drained to restore aerobic conditions, facilitating carbohydrate translocation to grains and easing harvest by firming the soil. This cyclic flooding-draining supports high yields through sustained moisture for tillering and panicle development, though it demands precise water control via gates and channels to avert excesses that could cause lodging or nutrient leaching. Overall, the design optimizes rice's semi-aquatic physiology, enabling double or triple cropping in suitable climates.[15][18]Historical Development
Origins in Neolithic East Asia
The origins of paddy fields trace to the Neolithic domestication and early cultivation of rice (Oryza sativa japonica) in the Lower Yangtze River basin of eastern China, where wet-field agriculture emerged as a response to the ecological preferences of wild rice species that thrived in marshy, seasonally flooded environments. Archaeological evidence indicates that initial rice management began around 10,000 years before present (BP), approximately 8000 BCE, during the Shangshan culture (ca. 11,000–8,400 BP), marked by the collection and possible early tending of wild rice stands rather than fully domesticated crops. Phytolith analyses from Shangshan sites reveal rice husks in pottery residues, suggesting processing of grains with reduced shattering—a key domestication trait—though fields were likely unmanaged wetlands at this stage.[19][20][21] By approximately 7000 BP (ca. 5000 BCE), sites such as Kuahuqiao provide the earliest direct evidence of intentional wet rice cultivation, involving human modifications to coastal swamps through fire clearance and flood management to create proto-paddy environments suitable for rice growth. Use-wear patterns on flaked stone tools from Lower Yangtze Neolithic sites (10,000–7000 BP) confirm harvesting practices adapted to dense, wet rice stands, with sickle-like implements for cutting stalks in flooded conditions, indicating a shift from opportunistic gathering to systematic field exploitation. These developments coincided with the Holocene climatic optimum, which expanded wetland habitats, facilitating the transition from dryland millet farming in northern China to irrigated rice systems in the humid south.[22][23] Paddy field construction, characterized by bunded plots to retain water, likely formalized around 6000–5000 BP in the Yangtze delta, as evidenced by sedimentary records of anthropogenic field features and increased rice domestication markers like larger grains and non-shattering rachises at sites including Hemudu and Tianluoshan. This wet-rice innovation boosted productivity over dry farming, enabling population growth and cultural complexity in Neolithic societies, though early paddies were small-scale and integrated with foraging economies. Genetic studies corroborate a single domestication event for japonica rice in this region, distinct from later indica varieties, underscoring the Yangtze's role as the primary cradle for paddy agriculture.[24][25]Spread across Asia
From its origins in the Yangtze River valley of China, where domesticated rice and early paddy fields emerged around 4000 BCE, rice cultivation spread northward and eastward along coastal and riverine routes.[3] Archaeological evidence indicates paddy field systems appeared in Shandong province by 2500 BCE, followed by South Korea around 1000 BCE, and Japan during the Yayoi period starting circa 300 BCE.[26] This dissemination was facilitated by wet-rice farming technologies adapted to temperate climates, enabling population growth and cultural shifts in these regions.[27] Southward expansion into mainland Southeast Asia accelerated in the late third millennium BCE, coinciding with migrations of Austroasiatic-speaking peoples and the development of intensified wet-rice systems.[28] Phytolith and grain remains from sites in Thailand and Vietnam confirm domesticated rice presence by 2000 BCE, with paddy fields supporting early complex societies.[29] Coastal environmental changes during the Late Holocene, including sediment deposition and salinity shifts, further enabled rapid paddy field proliferation along Asia's shorelines between 3000 and 2000 years ago.[30][31] Westward dispersal reached South Asia by approximately 2200 BCE, with archaeological finds of rice grains in the Ganges valley and Indus settlements indicating transfer via overland routes through the Himalayan foothills or maritime paths.[28][32] In northern India, evidence from Lahuradewa shows continuous rice exploitation from wild gathering to cultivation around 6000 BCE, though full domestication and paddy systems likely incorporated East Asian indica-japonica hybrids later.[33] This spread intertwined with millet farming in mixed systems, influencing linguistic and cultural patterns across language family homelands.[34] By the first millennium BCE, rice had become integral to agrarian economies from the Indian subcontinent to island Southeast Asia, underpinning urban centers and trade networks.[35]Global dissemination and adaptations
The practice of wet rice cultivation disseminated beyond mainland Asia primarily through the migrations of Austronesian peoples, who carried rice agriculture to Island Southeast Asia, the Pacific Islands, and Madagascar between approximately 3000 BCE and 1000 CE. Archaeological evidence indicates rice remains in sites across these regions, adapting to island environments with rainfed systems on volcanic soils and terraced fields in hilly terrains. In the Pacific, rice was cultivated pre-colonially on Guam and other Micronesian islands, though it competed with tuber crops like taro in many areas.[34] In Madagascar, Austronesian settlers introduced Asian rice (Oryza sativa) around 1000–500 BCE, integrating it into highland terraced paddies and lowland irrigated fields suited to the island's tropical climate. Local adaptations included shifting cultivation in deforested areas and later innovations like the System of Rice Intensification (SRI), developed in the 1980s, which optimizes spacing, water use, and soil aeration to boost yields without chemicals. By the 20th century, rice became Madagascar's staple, with production reaching over 4 million tons annually by 2020, though challenged by cyclones and soil degradation.[36] Rice reached the Americas during the colonial era, with Spanish explorers introducing O. sativa to Mexico in the 1520s and Portuguese to Brazil shortly after. Commercial paddy cultivation flourished in the English colonies of South Carolina from the late 17th century, where enslaved Africans contributed knowledge of Oryza glaberrima (African rice) and tidal irrigation techniques. Adaptations involved constructing dikes and trunks to harness coastal tides for flooding fields, enabling high yields in swampy lowlands; by 1770, South Carolina exported over 70,000 tons annually, supporting plantation economies until boll weevil and floods diminished it in the early 20th century.[37][38][39] In Europe, rice paddy systems emerged in the Iberian Peninsula under Moorish rule from the 8th century, spreading to Italy's Po Valley and Spain's Valencia region by the 15th century with Arab-influenced irrigation networks. Adaptations focused on Mediterranean climates, using river diversions and short-season varieties for double-cropping, though limited by cooler temperatures compared to Asian origins; modern European production, concentrated in Italy (over 1.4 million tons in 2020), employs mechanized flooding in reclaimed wetlands. African and Latin American adaptations similarly incorporated local ecologies, such as rainfed uplands in West Africa and flood-prone deltas in Brazil, blending Asian genetics with indigenous practices for resilience.[40]Agronomic Practices
Irrigation and water management
Paddy fields rely on flood or basin irrigation, where fields are leveled and enclosed by compacted bunds to retain standing water, typically 2-5 cm deep during the vegetative stage, to suppress weeds, control pests, and facilitate nutrient uptake under anaerobic conditions.[41] This method suits rice's physiological adaptation to submergence via aerenchyma tissues that transport oxygen to roots.[42] Water sources include rainfall in rainfed systems, rivers, reservoirs, and canals in irrigated setups, with field-to-field distribution via secondary channels to enable farmer-level control.[43] Traditional continuous flooding maintains ponded water from transplanting to near-maturity, but demands high volumes—global rice production consumes about 30-40% of irrigated freshwater, equating to 2,500-5,000 liters per kilogram of milled rice depending on soil and climate.[44] Inefficient percolation and seepage through bunds exacerbate losses, prompting practices like laser leveling to minimize uneven water distribution and reduce usage by up to 20%.[45] Historical systems, such as Bali's subak, integrate communal canals and weirs for equitable allocation across terraced fields.[46] To address water scarcity, alternate wetting and drying (AWD), developed by the International Rice Research Institute (IRRI), involves reflooding only when soil moisture drops 15 cm below the surface, monitored via perforated tubes, saving 15-30% irrigation water without yield penalties in many trials.[47] AWD also cuts methane emissions by 48% by limiting anaerobic periods.[48] Other innovations include subsurface drip irrigation, which delivers water directly to roots, potentially halving evaporation and percolation compared to surface flooding, though adoption lags due to infrastructure costs.[49] In water-stressed regions like southern China, optimized regimes have saved 7.7-9.5% water while boosting yields by 1.6-4.7%.[50] Challenges persist from over-irrigation causing soil salinization and aquifer depletion, particularly in intensive Asian systems where rice uses 25 times the scientifically optimal water in some areas. Effective management thus balances rice's flood tolerance with efficiency metrics, targeting water use efficiency above 0.5 kg rice per cubic meter through precise scheduling and infrastructure.[51]Soil preparation and nutrient management
Soil preparation for paddy fields begins with primary tillage, typically involving plowing to a depth of 15-20 cm using animal-drawn or tractor-mounted implements to break up compacted soil, incorporate crop residues, and control weeds after harvest.[52] This is followed by harrowing to pulverize clods and create a finer tilth, repeated 2-3 times in dry or moist conditions to achieve uniform soil structure.[53] Wet preparation, dominant in lowland systems, introduces flooding to 5-10 cm depth before secondary harrowing, transforming the process into puddling—churning saturated soil with rotary tillers or harrows to disperse clay particles and form a compacted, impermeable plow pan at 10-15 cm depth.[52] Puddling reduces percolation losses by up to 70% in clay-rich soils (9-64% clay content), enhancing water retention essential for anaerobic rice growth, but repeated application degrades soil structure, increasing bulk density, restricting root penetration in subsequent dryland crops, and forming large clods in fine-textured soils over multiple seasons.[54] Final leveling ensures even water distribution, minimizing uneven crop stands and optimizing flood depth control.[55] Nutrient management in paddy fields prioritizes nitrogen (N), phosphorus (P), and potassium (K), with rice requiring 100-150 kg N/ha, 30-60 kg P₂O₅/ha, and 30-60 kg K₂O/ha depending on soil fertility, yield targets (4-8 t/ha), and indigenous supply assessed via soil tests.[56][57] Flooded conditions alter nutrient dynamics: high iron and manganese availability supports growth, but phosphorus fixation into insoluble forms necessitates basal applications incorporated during puddling, while excess N promotes vegetative growth at the expense of grain fill if not split (e.g., 40% basal, 30% tillering, 30% panicle initiation).[58] Urea, the primary N source, suffers 20-40% volatilization losses in flooded soils unless deep-placed (5-10 cm) or applied during low-water periods; site-specific nutrient management (SSNM) principles, balancing yield goals with soil and plant diagnostics, can reduce N inputs by 10-20% while maintaining yields by accounting for residual nutrients from prior crops or organic amendments like green manures.[59] Organic inputs, such as 5-10 t/ha farmyard manure, enhance microbial activity and micronutrient supply (Zn, Fe) but decompose slowly under anaerobiosis, requiring integration with inorganic fertilizers for timely availability.[58] Over-application risks environmental leaching, with P thresholds above 74 kg P₂O₅/ha linked to runoff in high-rainfall areas, underscoring soil testing (e.g., Olsen P levels >20 ppm indicating sufficiency) to avoid excesses.[60] Long-term puddling exacerbates nutrient stratification, confining P and K to surface layers and necessitating targeted deep incorporation for root access.[61]Planting, growth, and harvesting techniques
In paddy fields, rice establishment primarily occurs through transplanting or direct seeding. Transplanting entails raising seedlings in nurseries for 15–21 days before transferring them to the puddled main field, using approximately 40 kg of seed per hectare with 2–3 seedlings per hill.[62] This labor-intensive process, requiring 25–30 person-days per hectare, enhances weed suppression through established plant vigor and precise spacing, such as 20 × 20 cm in straight rows, which can boost yields by 25–40%.[63] Direct seeding involves broadcasting or drilling pregerminated seeds directly into the field at 60–80 kg per hectare, offering labor savings and faster maturity but heightening risks from weeds and pests, necessitating synchronized planting with adjacent fields and early snail control.[62] The choice between methods depends on local resources, soil conditions, and labor availability, with transplanting predominant in irrigated Asian paddies for its agronomic advantages.[62] Rice growth proceeds in three phases: vegetative, reproductive, and ripening. The vegetative phase, spanning 45–65 days from establishment to panicle initiation (e.g., 45 days for IR64 variety), focuses on tillering, root development, and biomass accumulation under flooded conditions to optimize nutrient uptake and weed control.[64] The reproductive phase lasts about 35 days, involving panicle exertion and flowering, where water stability prevents spikelet sterility.[64] Ripening, approximately 30 days, entails grain filling and maturation, with management emphasizing minimal stress for full kernel development.[64]
Harvesting commences at physiological maturity, when grain moisture is 20–25% to curtail losses from shattering or delayed operations. Manual methods employ sickles for reaping panicles or straw, followed by threshing via beating or treading to extract grains, and winnowing for cleaning, suitable for smallholder systems.[65] Mechanical combines integrate cutting, threshing, and separation for efficiency in larger operations, though they demand field accessibility. Post-harvest handling includes hauling, drying to 14% moisture via sun exposure or artificial means to avert spoilage, and storage preparation.[65]
Environmental Impacts
Ecosystem services and biodiversity
Paddy fields function as artificial wetlands, delivering multiple ecosystem services beyond primary crop production. These include regulating services such as flood mitigation through water retention and detention, where inundated fields absorb excess rainfall and reduce downstream flooding risks; studies in Japan quantify this capacity at up to 100-200 mm of water storage per hectare during peak seasons.[66] Groundwater recharge is another key service, with percolated irrigation water replenishing aquifers, estimated to contribute 20-50% of annual recharge in intensive rice-growing regions like the Indo-Gangetic Plain.[67] Soil conservation occurs via rice root systems that stabilize slopes and minimize erosion, particularly in terraced systems, preventing nutrient loss and landslide initiation in hilly terrains.[68] Habitat provisioning supports diverse taxa, acting as refugia for aquatic and semi-aquatic species during flooded phases. Paddy fields harbor fish populations through integrated aquaculture, yielding secondary protein sources while enhancing nutrient cycling via fish excretion; in Southeast Asia, such systems boost fish yields by 200-500 kg per hectare annually.[69] Natural pest regulation emerges from predator-prey dynamics, with birds, amphibians, and insects controlling rice pests; for instance, dragonflies and frogs consume up to 30% of insect pests in unmanaged fields.[70] Carbon sequestration in soils, though offset by methane emissions elsewhere, accumulates organic matter at rates of 0.5-1.5 tons of carbon per hectare yearly under continuous flooding.[71] Biodiversity in paddy fields rivals that of natural wetlands in certain metrics, sustaining high abundances of macroinvertebrates, birds, and amphibians despite agricultural intensification. In eastern Taiwan, organic paddies exhibit arthropod diversity indices 1.5-2 times higher than conventional ones, serving as indicators of agrobiodiversity.[72] Bird communities thrive, with Japanese surveys recording 55 species and abundances of 176 individuals per kilometer transect, often exceeding forest understories for water-dependent species.[73] Amphibian restoration in Chinese paddies has increased populations by factors of 3-5 following habitat enhancements like refuge ponds.[74] However, field abandonment reduces species richness by 28-44% for plants and invertebrates, underscoring the dynamic habitat value of maintained paddies over fallow land.[75] These services hinge on traditional management practices, with biodiversity hotspots in diversified systems integrating fish, ducks, and wild refuges; meta-analyses confirm that agrochemical reduction elevates overall biotic richness without yield penalties in low-input contexts.[76] In water-scarce adaptations, paddies in storage zones can supplant lost wetland functions, hosting endemic species while regulating hydrology.[77] Empirical data from multi-site evaluations in China rank habitat and regulating services as contributing 40-60% of total ecosystem value in typical paddies, rivaling provisioning in sustainability assessments.[78]Negative effects on climate and resources
Paddy fields contribute substantially to global greenhouse gas emissions, primarily through methane (CH4) production under anaerobic conditions in flooded soils, where organic matter decomposition by methanogenic archaea generates approximately 25-37 Tg of CH4 annually, representing 6-12% of total anthropogenic methane emissions.[79] [80] [81] This process is exacerbated by practices such as continuous flooding and incorporation of rice residues, which provide substrates for microbial CH4 formation.[82] Rice cultivation also emits nitrous oxide (N2O), mainly from nitrogen fertilizer application and soil nitrification-denitrification, accounting for about 11% of agricultural N2O emissions globally; intermittent drainage in paddies can amplify N2O release by up to 45 times compared to continuous flooding. [83] These emissions intensify climate forcing, as CH4 has a global warming potential 28-34 times that of CO2 over 100 years, while N2O is over 260 times more potent.[81] In aggregate, rice systems contribute 22% of agricultural CH4 and 11% of N2O, with total GHG footprints varying by management but often exceeding 1-4 tons of CO2-equivalent per hectare per season in intensive Asian production. [84] On resources, paddy rice demands intensive water inputs, consuming roughly 40% of global irrigation water despite occupying only 10-15% of harvested cropland, with an average water footprint of 1,325 m3 per ton of paddy rice produced (48% green water from rain, 44% blue from irrigation, 8% grey from pollution dilution).[85] [86] This high usage strains aquifers and rivers in water-scarce regions like South Asia and China, where over-pumping for flood irrigation has depleted groundwater levels by meters per decade in some basins and contributed to salinization in coastal deltas.[87] Soil resources face degradation from puddling, a preparatory practice that compacts subsoils, reduces permeability, and impairs drainage, leading to long-term declines in soil structure, organic matter, and fertility; repeated cycles accelerate acidification (pH drops of 0.5-1 unit over years) and nutrient imbalances, particularly in intensive rotations.[88] Fertilizer overuse in paddies further promotes eutrophication via runoff, indirectly taxing downstream water quality as a resource, while monoculture dominance limits soil microbial diversity essential for sustained productivity.[89]Mitigation strategies and sustainable innovations
Techniques such as alternate wetting and drying (AWD) or intermittent aeration can reduce methane emissions from rice paddies by 20-50% by periodically drying the fields to introduce oxygen and suppress anaerobic methane production.[90][91] AWD irrigation, which involves periodically drying paddy fields to a specific soil moisture level before re-flooding, reduces methane emissions by 30-50% compared to continuous flooding while saving 20-30% of irrigation water and maintaining or slightly increasing yields in many field trials. This technique disrupts anaerobic conditions favoring methanogenic bacteria, with eddy covariance measurements confirming emission cuts without yield penalties in direct-seeded systems.[92] AWD's efficacy has been demonstrated across Asia, including in China and India, where it also lowers nitrous oxide emissions under optimized nitrogen use.[93] The System of Rice Intensification (SRI) promotes wider plant spacing, younger seedlings, intermittent irrigation akin to AWD, and organic soil amendments to foster robust root systems and microbial activity, yielding 20-100% higher outputs with 30-50% less water and up to 90% reduced seed rates.[94] SRI enhances soil organic matter and biodiversity, indirectly curbing methane through aerobic soil phases and improved nutrient efficiency, with adoption in over 50 countries showing resilience to drought and pests.[95] Field studies indicate SRI lowers greenhouse gas intensity per unit yield by promoting vigorous tillering and reducing chemical inputs.[96] Biochar incorporation from rice straw reduces methane emissions by up to 86% in paddy soils by enhancing aeration and microbial oxidation, as evidenced in two-year trials in eastern China, while improving soil carbon sequestration and fertility.[97] Complementary straw management, such as off-season incorporation or conversion to biochar, avoids excess organic inputs that boost anaerobic decomposition.[98] Precision nutrient application, including site-specific fertilizer dosing, minimizes nitrous oxide releases and excess nitrogen fueling methane production.[99] Innovations from institutions like the International Rice Research Institute (IRRI) include low-methane rice cultivars and direct-seeding methods, which cut tillage-related emissions and water needs, integrated within standards like the Sustainable Rice Platform for scalable adoption.[100] Bacterial inoculants, such as Azoarcus strains on seeds, suppress methanogenesis by 17-24%, offering a biological adjunct to cultural practices.[101] These strategies collectively address rice's contribution to 48% of cropland methane, prioritizing empirical field data over modeled projections for verifiable reductions.Socioeconomic Importance
Role in global food security and economy
Paddy fields underpin global food security by producing rice, the primary staple for over half the world's population, exceeding 3.5 billion people, with Asia accounting for the vast majority of consumption.[102][103] Rice provides approximately 20% of global caloric intake and up to 80% of daily calories for many in rice-dependent regions like South and Southeast Asia.[104] Disruptions in paddy production, such as those from weather variability, directly threaten nutritional stability in low-income households, where rice constitutes a core buffer against hunger.[105] Global rice production reached 523.73 million metric tons (milled equivalent) in the 2023/2024 marketing year, with projections for continued growth driven by yield improvements in Asia, where 90% of output occurs.[8] China and India dominate, producing over 40% of the total, followed by Indonesia, Bangladesh, and Vietnam.[106] This output supports domestic needs in populous nations while enabling exports that stabilize food supplies in import-reliant countries across Africa and Latin America.[102] However, production growth lags behind demand forecasts, necessitating a 15-20% increase by mid-century to avert shortages amid population pressures.[107] Economically, paddy cultivation sustains rural livelihoods for hundreds of millions, particularly in developing economies where it generates significant employment and contributes substantially to agricultural GDP—up to 20-30% in countries like Vietnam and Thailand.[108] The global rice trade, valued at tens of billions annually, features key exporters like India, Thailand, and Vietnam supplying 30-40% of traded volumes, bolstering foreign exchange reserves and food aid programs.[102] In aggregate, rice supports poverty alleviation by linking smallholder farmers to markets, though inefficiencies in water use and low mechanization constrain productivity gains essential for long-term economic resilience.[105]Labor, productivity, and technological shifts
Paddy rice cultivation has historically demanded intensive manual labor, especially in Asia, which accounts for over 90% of global production. Key tasks such as seedling transplanting, hand-weeding, and sickle-based harvesting require substantial human input, often peaking seasonally and engaging rural households extensively.[109] In regions like Central Java, Indonesia, labor productivity in lowland paddy systems averages 1.5 quintals per human working day, reflecting the efficiency limits of manual methods.[110] The Green Revolution, commencing in the 1960s, marked a pivotal technological shift through high-yielding varieties (HYVs), chemical fertilizers, and improved irrigation, which substantially elevated productivity. In Asia, average rice yields rose from approximately 2 metric tons per hectare in the early 1960s to over 4 metric tons per hectare by the 1990s, driven primarily by HYV adoption and input intensification.[111] For instance, the IR8 variety tested in the Philippines achieved yields up to 9.4 metric tons per hectare, far exceeding traditional averages of about 1 metric ton per hectare.[112] These gains stemmed from genetic improvements enabling denser planting and better fertilizer responsiveness, though sustained yield increases have moderated since the 1980s due to diminishing returns and biophysical constraints.[113] Mechanization has progressively substituted labor, enhancing productivity amid rural depopulation and wage rises in Asia. Adoption of walking transplanters and combine harvesters has reduced planting time by up to 90% and harvesting costs by 60%, while boosting labor productivity by more than 40% and cutting overall production expenses by 20%.[114][115] In countries like China and Vietnam, widespread mechanization since the 2000s has increased timeliness of operations, minimizing crop losses and enabling double-cropping, with regional yields now averaging 6 metric tons per hectare.[116] However, smallholder dominance—average farm sizes under 1 hectare in many areas—limits full mechanization, prompting innovations like custom-hire services and smaller-scale equipment.[117] Recent advancements, including precision tools like GPS-guided machinery and drone-based monitoring, further optimize input use and yields, though their impact remains concentrated in higher-income Asian producers. By 2021, Asia's rice yield per hectare reached 6.07 metric tons, underscoring ongoing productivity gains from integrated technological adoption despite challenges like soil degradation.[118] These shifts have alleviated labor burdens but necessitate policy support for equitable access to maintain socioeconomic viability in paddy systems.[119]Cultural and social dimensions
Paddy fields hold profound cultural symbolism across rice-dependent societies, representing fertility, prosperity, and communal sustenance. In many Asian traditions, rice harvested from paddies is integral to rituals honoring ancestors and deities, with offerings ensuring bountiful yields and social harmony. For instance, in Balinese Hinduism, the subak irrigation system integrates paddy cultivation with spiritual practices, guided by water temple priests who synchronize planting cycles with temple ceremonies to maintain ecological and cosmic balance under the Tri Hita Karana philosophy of harmony between humans, nature, and the divine.[120] This system, dating to the 9th century, organizes farmers into democratic assemblies for equitable water distribution, embedding social governance in agricultural routines.[121] Festivals tied to paddy cycles reinforce these cultural ties, blending labor with celebration. Nepal's Ropain Diwas on June 29 features ritual planting accompanied by folk songs and community feasts, invoking deities for rain and growth.[122] In India, Pongal in Tamil Nadu (January 14–17) involves boiling fresh paddy in milk as an offering to the sun god, symbolizing gratitude for the harvest.[123] Japan's Otaue festival at Sumiyoshi Taisha Shrine on June 14 reenacts ancient planting with dances, songs, and oxen-drawn plows, preserving Shinto rites for rice deity Inari.[124] Such events, observed annually, foster intergenerational transmission of knowledge and reinforce paddy fields as sacred landscapes rather than mere economic assets.[125] Socially, wet-rice paddy systems demand intensive, coordinated labor, shaping collectivist norms distinct from less labor-dependent crops like wheat. Empirical studies in China reveal that historical rice-farming regions exhibit tighter social reciprocity and interdependence, with labor needs twice those of dryland farming promoting village-level mutual aid to avert crop failure.[126] Quasi-experimental evidence from Vietnam confirms rice cultivators display greater loyalty to kin over strangers and relational thinking compared to non-rice groups, attributing this to shared irrigation dependencies requiring trust and cooperation.[127] In Southeast Asia, rice's centrality extends to village identity, where paddy work builds relational networks and resilience through familial commitments, though modernization erodes these ties.[128][129] Gender dynamics in paddy farming highlight women's disproportionate involvement amid unequal control. Across Asia and Africa, women supply 50–90% of labor for transplanting, weeding, and post-harvest processing, tasks suited to their availability during peak seasons, yet men often dominate land ownership, input decisions, and mechanization benefits.[130][131] In south-western Nigeria, this yields a 29% productivity gap favoring men due to women's limited access to credit and extension services.[131] While rice's labor intensity elevates female participation, it reinforces traditional divisions without necessarily advancing equity, as cultural norms normalize women's fieldwork without commensurate authority.[132] These patterns underscore paddy fields' role in perpetuating gendered social structures tied to subsistence imperatives.[133]Challenges and Debates
Climate change vulnerabilities
Paddy fields, reliant on consistent water regimes and moderate temperatures for rice cultivation, face heightened vulnerabilities from climate change, including elevated temperatures, altered precipitation patterns, and sea-level rise. Empirical studies indicate that global rice yields could decline by up to 40% by the end of the century under high-emission scenarios, driven primarily by heat stress and water variability rather than CO2 fertilization benefits.[134][135] Heat stress during critical growth stages, such as flowering and grain filling, disrupts pollen viability and spikelet fertility, with rice exhibiting a seed-set threshold at approximately 37.2°C.[136] For instance, temperatures exceeding 35°C for more than three days at flowering inhibit anther dehiscence and pollen shedding, leading to sterility rates that can reduce yields by 10% per 1°C rise in average growing-season temperature.[137][138] Water-related extremes exacerbate these risks, as paddy systems demand precise flooding for weed control and nutrient uptake. Droughts during vegetative or reproductive phases limit irrigation needs but cause stomatal closure and reduced photosynthesis, with regional analyses showing minimal short-term yield buffering from residual soil moisture in Asia's major rice belts.[139] Conversely, intensified flooding from erratic monsoons or cyclones submerges fields, delaying planting and promoting anaerobic conditions that favor pests and diseases; in lowland systems, such events have been linked to yield losses of up to 20-30% in affected areas like Vietnam's Mekong Delta.[140][141] Coastal paddies, comprising about 20% of global rice land, are particularly susceptible to sea-level rise-induced salinization, where saltwater intrusion elevates soil salinity beyond rice's tolerance (typically 3-4 dS/m). Projections for regions like the Ebro Delta forecast a tripling of salinity by 2100 under worst-case scenarios, slashing production from 61% to 34% of current levels.[142] In Bangladesh's coastal zones, median annual salinity increases of 1-2 dS/m per decade already threaten 10-15% of arable land, compounding freshwater scarcity and forcing shifts to salt-tolerant varieties with lower productivity.[143] These vulnerabilities are regionally variable, with tropical Asia—producing 90% of the world's rice—projected to see the sharpest declines absent adaptive measures.[144][145]Land use conflicts and conversions
Rapid urbanization and industrialization in Asia's major rice-producing regions have driven significant conversions of paddy fields to non-agricultural uses, creating tensions between short-term economic gains and long-term food security. In densely populated countries like China, India, and Indonesia, where paddy fields constitute a large share of arable land, developers prioritize urban expansion and infrastructure, often acquiring farmland at below-market rates, leading to farmer displacement and reduced rice output capacity. For instance, China's "red line" policy mandates preserving at least 120 million hectares of arable land to sustain domestic food needs, yet conversions persist due to local government incentives for GDP growth through construction.[146][147] Between 1990 and 2020, paddy field conversions in China were concentrated in low-elevation areas suitable for development, contributing to overall farmland shrinkage since the 1950s.[148][149] In Indonesia, paddy land losses exemplify the scale of conversions, with an average annual reduction rate of -5.67% across provinces, and approximately 1.22 million hectares of rice fields converted overall, largely to urban and industrial zones.[150][151] A geospatial analysis in one Indonesian region revealed that urban expansion replaced 23% of paddy fields between 1989 and 2021, exacerbating production vulnerabilities in areas already strained by population growth.[152] Similar patterns in Southeast Asia project cropland declines exceeding 10% in countries like Indonesia, Malaysia, the Philippines, and Vietnam without intervention, as infrastructure and real estate encroach on flood-prone but fertile paddy terrains.[153] Land use conflicts often manifest as protests by farmers opposing coerced acquisitions that prioritize industrial projects over agricultural viability. In India, rice and sugarcane cultivators have mobilized against state-led land grabs for factories and highways, as seen in 2010 demonstrations where farmers rejected inadequate compensation for fertile fields, arguing it undermined their livelihoods and national grain supplies.[154] Ongoing disputes in states like Karnataka and Punjab highlight how such conversions fuel distress sales and stagnate rice yields, with protesters demanding fair valuation and alternatives to sacrificing prime paddy land.[155][156] In China, while centralized policies aim to balance development with the red line, local implementations have sparked grievances over opaque reallocations, though state control limits widespread unrest compared to democratic India. These conflicts underscore causal trade-offs: conversions boost immediate employment and revenue but erode the irrigated, high-yield paddy systems essential for feeding billions, with empirical data showing correlated drops in regional rice self-sufficiency.[157]Controversies over traditional vs. modern methods
Modern rice cultivation methods, introduced widely through the Green Revolution from the 1960s onward, emphasize high-yielding varieties, synthetic fertilizers, pesticides, and mechanization to achieve substantially higher productivity than traditional practices. Global average rice yields rose from approximately 2 tons per hectare in 1961 to 4.7 tons per hectare by 2020, driven by these innovations that enabled surplus production to support population growth in Asia. However, critics argue that such intensive approaches accelerate environmental degradation, including eutrophication from fertilizer runoff and groundwater depletion due to expanded irrigated areas covering 55% of global rice production by 2019.[158] Traditional paddy farming, characterized by labor-intensive transplanting, flood irrigation with indigenous varieties, and reliance on organic manures, maintains lower input costs and potentially higher resilience to local pests but yields only 2-3 tons per hectare on average, insufficient for food security in densely populated regions.[159] These methods, while preserving soil microbial diversity and reducing chemical pollution, contribute significantly to methane emissions—rice paddies account for 10-12% of global anthropogenic methane, primarily from anaerobic conditions in flooded fields common to both systems yet unmanaged in traditional setups.[160] Debates intensify over whether traditional practices inherently promote sustainability, as empirical studies show they often lead to field expansion into marginal lands, exacerbating deforestation and biodiversity loss when yields fail to meet demand.[161] The System of Rice Intensification (SRI), promoted since the 1980s as an intermediate approach, claims 20-50% yield increases with 25-50% less water and fewer seeds through wider spacing, intermittent irrigation, and organic amendments, challenging the necessity of chemical-intensive modern methods.[162] Yet, SRI faces controversy over inconsistent results across trials, with some peer-reviewed assessments attributing gains to better management rather than inherent superiority, and limited uptake due to higher initial labor demands that deter smallholders accustomed to mechanized alternatives.[163] Mechanization in modern harvesting reduces grain losses from 10-15% in manual traditional methods to under 2%, but displaces rural labor, contributing to social unrest and migration in countries like India where small farms predominate.[164][165] Economically, modern methods' dependency on subsidized inputs fosters vulnerability to price volatility, as seen in fertilizer crises inflating costs by 200% in 2022 for Asian farmers, while traditional systems offer stability but constrain scalability and market competitiveness.[159] Proponents of traditional revival, often from agroecological perspectives, cite reduced health risks from pesticide exposure—linked to 385 million annual cases of acute poisoning globally—but overlook productivity gaps that perpetuate poverty cycles in rice-dependent economies.[166] Overall, these controversies underscore a causal tension between short-term yield imperatives and long-term ecological viability, with no consensus on optimal paths amid varying regional contexts.[163]References
- https://en.wiktionary.org/wiki/paddy