97-398: Dioscorea alata – also called ube ( / ˈ uː b ɛ , - b eɪ / ), ubi , purple yam , or greater yam , among many other names – is a species of yam (a tuber ). The tubers are usually a vivid violet - purple to bright lavender in color (hence the common name), but some range in color from cream to plain white. It is sometimes confused with taro and
194-554: A noxious weed outside cultivated areas. Yams are cultivated for the consumption of their starchy tubers in many temperate and tropical regions, especially in West Africa, South America and the Caribbean , Asia, and Oceania . About 95% of yam crops are grown in Africa. A yam crop begins when whole seed tubers or tuber portions are planted into mounds or ridges, at the beginning of
291-411: A tuber . Some 870 species of yams are known, a few of which are widely grown for their edible tuber but others of which are toxic (such as D. communis ). Yam plants can grow up to 15 metres (49 feet) in length and 7.6 to 15.2 centimetres (3 to 6 inches) high. The tuber may grow into the soil up to 1.5 m (5 ft) deep. The plant disperses by seed . The edible tuber has a rough skin that
388-620: 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." In recent years, rice consumption in Japan has fallen and many rice farmers are increasingly elderly. The government has subsidized rice production since
485-464: A fresh-weight basis. Yams, with cassava , provide a much greater proportion of the protein intake in Africa, ranging from 5.9% in East and South Africa to about 15.9% in humid West Africa. As a relatively low-protein food, yam is not a good source of essential amino acids . Experts emphasize the need to supplement a yam-dominant diet with more protein-rich foods to support healthy growth in children. Yam
582-630: A good indicator of human movement. Some authors have proposed, without evidence, an origin in Mainland Southeast Asia , but it shows the greatest phenotypic variability in the Philippines and New Guinea . Based on archaeological evidence of early farming plots and plant remains in the Kuk Swamp site, authors have suggested that it was first domesticated in the highlands of New Guinea from around 10,000 BP and spread into Island Southeast Asia via
679-542: A great potential for increased production. D. hirtiflora subsp. pedicellata , lusala, busala or lwidi, is native to Tropical Africa . It is widely harvested and eaten in Southern Zambia where it grows in open forest areas. In Southern Zambia, it is an important addition to the March–September diets of almost all, and income of over half of rural households. Research on propagation of this subspecies to alleviate
776-753: A moister texture than sweet potatoes. Purple yams also have higher anthocyanin content than sweet potatoes. They can otherwise be used interchangeably in most recipes. Although available as a dietary supplement and used in folk medicine , there is no clinical evidence that D. alata has any therapeutic properties. Use of D. alata supplements may have adverse effects in people taking estrogens , anticoagulant drugs or during pregnancy and breast-feeding. Some people may have allergic reactions to use of D. alata supplements. D. alata has relatively high levels of oxalates (486–781 mg/100 g dry matter), which are associated with antinutritional effects and kidney stone formation. The color of purple varieties
873-496: 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
970-760: A practice that complicates harvesting in some cases. In forested areas, tubers grow in areas where other tree roots are present. Harvesting the tuber then involves the additional step of freeing them from other roots. This often causes tuber damage. Aerial tubers or bulbils are harvested by manual plucking from the vine. Yields may improve and cost of yam production be lower if mechanization were to be developed and adopted. However, current crop production practices and species used pose considerable hurdles to successful mechanization of yam production, particularly for small-scale rural farmers. Extensive changes in traditional cultivation practices, such as mixed cropping, may be required. Modification of current tuber harvesting equipment
1067-433: A preferred food and a culturally important food security crop in some sub-Saharan African countries. The following table shows the nutrient content of yam and major staple foods in a raw harvested form on a dry weight basis to account for their different water contents. Raw forms, however, are not edible and cannot be digested. These must be sprouted, or prepared and cooked for human consumption. In sprouted or cooked form,
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#17328517502381164-468: 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
1261-464: A single large tuber per year, generally weighing 5 to 10 kilograms (11 to 22 pounds). Yams suffer from relatively few pests and diseases. There is an anthracnose caused by Colletotrichum gloeosporioides which is widely distributed around the world's growing regions. Winch et al. , 1984 finds C. gloeosporioides afflicts a large number of Dioscorea spp. Despite the high labor requirements and production costs, consumer demand for yam
1358-409: A vessel of salt water, in cold or hot fresh water or in a stream. The bitter compounds in these yams are water-soluble alkaloids which, on ingestion, produce severe and distressing symptoms. Severe cases of alkaloid intoxication may prove fatal. Aerial or potato yams ( D. bulbifera ) have antinutritional factors. In Asia, detoxification methods, involving water extraction, fermentation, and roasting of
1455-561: 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
1552-438: Is an important dietary element for Nigerian and West African people. It contributes more than 200 calories per person per day for more than 150 million people in West Africa, and is an important source of income. Yam is an attractive crop in poor farms with limited resources. It is rich in starch, and can be prepared in many ways. It is available all year round, unlike other, unreliable, seasonal crops. These characteristics make yam
1649-483: 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
1746-590: Is considered the main rice growing province of the Philippines . 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. 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
1843-457: 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,
1940-587: Is difficult to peel but readily softened by cooking. The skins vary in color from dark brown to light pink. The majority, or meat, of the vegetable is composed of a much softer substance ranging in color from white or yellow to purple or pink in mature yams. The name "yam" appears to derive from Portuguese inhame or Canarian Spanish ñame , which derived from Fula , one of the West African languages during trade. However, in Portuguese, this name commonly refers to
2037-617: Is due to various anthocyanin pigments. The pigments are water-soluble, and have been proposed as possible food coloring agents. D. alata is sometimes grown in gardens for its ornamental value. Dioscorea alata is native to the Philippines, as well as surrounding areas ( Taiwan and the Ryukyu Islands of Japan ). It has escaped from its native growth area and into the wild in many other places, becoming naturalized in parts of southern and east-central China , Africa and Madagascar ,
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#17328517502382134-457: 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 ). 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
2231-564: Is grown in Northern Italy, especially in the valley of the Po River . 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. The acidic soil conditions common in Japan due to volcanic eruptions have made
2328-492: 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. The word "paddy" is derived from the Malay / Indonesian word padi , meaning "rice plant", which is itself derived from Proto-Austronesian *pajay ("rice in
2425-578: Is high in certain subregions of Africa, making yam cultivation quite profitable to certain farmers. Many cultivated species of Dioscorea yams are found throughout the humid tropics. The most economically important are discussed below. Non- Dioscorea tubers that were historically important in Africa include Plectranthus rotundifolius (the Hausa potato) and P. esculentus (the Livingstone potato); these two tuber crops have now been largely displaced by
2522-465: 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
2619-474: Is most common in Philippine cuisine (where it is known as ube or ubi ). It is widely applied for many Philippine desserts, such as ube cake , ube cheesecake and ube crinkles , as well as an ingredient or flavor for ice cream , milk , donuts , tarts , jam and other types of pastries . It is often eaten boiled, baked, or as a sweetened dessert called ube halayá ; the latter being a popular ingredient in
2716-547: Is native to China . The Chinese yam plant is somewhat smaller than the African, with the vines about 3 m (10 ft) long. It is tolerant to frost and can be grown in much cooler conditions than other yams. It is also grown in Korea and Japan . It was introduced to Europe in the 19th century, when the potato crop there was falling victim to disease, and is still grown in France for
2813-838: Is necessary given yam tuber architecture and its different physical properties. In 2020, world production of yams was 75 million metric tons (74,000,000 long tons; 83,000,000 short tons), led by Nigeria with 67% of the total (table). Unlike cassava , most varieties of edible, mature, cultivated yam do not contain toxic compounds. However, there are exceptions. Bitter compounds tend to accumulate in immature tuber tissues of white and yellow yams. These may be polyphenols or tannin -like compounds. Wild forms of bitter yams ( D. dumetorum ) do contain some toxins, such as dihydrodioscorine , that taste bitter, hence are referred to as bitter yam. Bitter yams are not normally eaten except at times of desperation in poor countries and in times of local food scarcity. They are usually detoxified by soaking in
2910-542: 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. Rice
3007-428: Is preferred by most people. However, it is popular in home vegetable gardens because it produces a crop after only four months of growth and continues producing for the life of the vine, as long as two years. Also, the bulbils are easy to harvest and cook. In 1905, the air potato was introduced to Florida and has since become an invasive species in much of the state. Its rapid growth crowds out native vegetation and it
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3104-616: Is referred to by many different names in these regions. In English alone, aside from purple yam, other common names include ten-months yam , water yam , white yam , winged yam , violet yam , Guyana arrowroot , or simply yam . Dioscorea alata is one of the most important staple crops in Austronesian cultures . It is one of various species of yams that were domesticated and cultivated independently within Island Southeast Asia and New Guinea for their starchy tubers , including
3201-477: Is said that they have also been used for criminal purposes. D. trifida , the cush-cush yam, is native to the Guyana region of South America and is the most important cultivated New World yam. Since they originated in tropical rainforest conditions, their growth cycle is less related to seasonal changes than other yams. Because of their relative ease of cultivation and their good flavor, they are considered to have
3298-485: Is second only to white yam. The tuber shape is generally cylindrical, but can vary. Tuber flesh is white and watery in texture. D. alata and D. esculenta (lesser yam) were important staple crops to the seafaring Austronesian cultures. They were carried along with the Austronesian migrations as canoe plants , from Island Southeast Asia to as far as Madagascar and Polynesia . D. polystachya , Chinese yam,
3395-606: 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. Rice appears to have been used by
3492-450: Is very difficult to remove since it can grow back from the tubers, and new vines can grow from the bulbils even after being cut down or burned. D. esculenta , the lesser yam, was one of the first yam species cultivated. It is native to Southeast Asia and is the third-most commonly cultivated species there, although it is cultivated very little in other parts of the world. Its vines seldom reach more than 3 m (10 ft) in length and
3589-1139: The Camargue in France , 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. Paddy cultivation should not be confused with cultivation of deepwater rice , which
3686-855: The Comoros , and the coast of East Africa around the 1st millennium AD by Austronesian settlers from the Greater Sunda Islands . 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 . 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
3783-526: 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
3880-565: The Lapita culture at around c. 4,000 BP , along with D. nummularia and D. bulbifera . In turn, D. esculenta is believed to have been introduced by the Lapita culture into New Guinea. There is also evidence of an agricultural revolution during this period brought by innovations from contact with Austronesians, including the development of wet cultivation . However, much older remains identified as being probably D. alata have also been recovered from
3977-611: The Malaysian 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 Malaysia's east coast region, in Kelantan and Terengganu . The central state of Selangor also has its fair share of paddy fields, especially in the districts of Kuala Selangor and Sabak Bernam . Before Malaysia became heavily reliant on its industrial output, people were mainly involved in agriculture, especially in
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4074-526: The Niah Caves of Borneo ( Late Pleistocene , <40,000 BP ) and the Ille Cave of Palawan (c. 11,000 BP ), along with remains of the toxic ubi gadong ( D. hispida ) which requires processing before it can be edible. Although it doesn't prove cultivation, it does show that humans already had the knowledge to exploit starchy plants and that D. alata were native to Island Southeast Asia. Furthermore, it opens
4171-598: The Pacific Islands and New Zealand . They were also carried by Austronesian voyagers into Madagascar and the Comoros . The center of origin of purple yam is in the Philippines , but archaeological evidence suggests that it was exploited in Island Southeast Asia and New Guinea before the Austronesian expansion . Purple yam is believed to be a true cultigen , only known from its cultivated forms. The vast majority of cultivars are sterile, which restricts its introduction into islands purely by human agency, making them
4268-541: 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. Rice did not survive
4365-579: 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. These developments were widely spread during
4462-830: The Western Hemisphere , and various islands in the Indian and Pacific oceans. It persists in the wild in Haiti, as well as the United States , in Louisiana , Georgia , Alabama , Puerto Rico , the U.S. Virgin Islands , and in Florida where it is considered an invasive species . Yam (vegetable) Yam is the common name for some plant species in the genus Dioscorea (family Dioscoreaceae ) that form edible tubers (some other species in
4559-405: The bulbils which grow at the base of its leaves are the more important food product. They are about the size of potatoes (hence the name "air potato"), weighing from 0.5 to 2.0 kg (1 lb 2 oz to 4 lb 7 oz). Some varieties can be eaten raw, while some require soaking or boiling for detoxification before eating. It is not grown much commercially since the flavor of other yams
4656-523: 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. Paddy fields can be found in most states on
4753-649: The taro plant ( Colocasia esculenta ) from the genus Colocasia , as opposed to Dioscorea . The main derivations borrow from verbs meaning "to eat". True yams have various common names across multiple world regions. In some places, other (unrelated) root vegetables are sometimes referred to as "yams", including: Yams are native to Africa, Asia, and the Americas. Three species were independently domesticated on those continents: D. rotundata (Africa), D. alata (Asia), and D. trifida (South America). Some yams are invasive plants , often considered
4850-504: The 1970s, and favors protectionist policies regarding cheaper imported rice. 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
4947-483: The Asian food market. The tubers are harvested after about 6 months of growth. Some are eaten right after harvesting and some are used as ingredients for other dishes, including noodles, and for traditional medicines. D. bulbifera , the air potato, is found in both Africa and Asia, with slight differences between those found in each place. It is a large vine, 6 m (20 ft) or more in length. It produces tubers, but
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#17328517502385044-586: 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 . Rice and wet-field agriculture were also introduced to Madagascar ,
5141-661: The Early Neolithic populations of Lijiacun and Yunchanyan in China. 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. 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
5238-623: 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 . 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
5335-581: The Middle Jeulmun pottery period (c. 3500–2000 BC) in the Korean Peninsula . 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
5432-603: 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 . Prime Javanese paddies yield roughly 6 metric tons of unmilled rice (2.5 metric tons of milled rice) per hectare . When irrigation
5529-503: The Okinawa sweet potato beniimo ( 紅芋 ) ( Ipomoea batatas cv. Ayamurasaki ), however D. alata is also grown in Okinawa. With its origins in the Asian and Oceanian tropics , D. alata has been known to humans since ancient times. Because it has become naturalized following its origins in Asia, specifically the Philippines , through tropical South America, and the southeastern U.S., D. alata
5626-618: The Okinawan purple "yam", which is a sweet potato ), greater yam, winged yam, water yam, and (ambiguously) white yam, was first cultivated in Southeast Asia. Although not grown in the same quantities as the African yams, it has the largest distribution worldwide of any cultivated yam, being grown in Asia, the Pacific islands, Africa, and the West Indies. Even in Africa, the popularity of water yam
5723-408: The Yangtze River in present-day China. 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 . The second
5820-402: 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. 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
5917-461: The Yangtze was probably the site of the earliest rice cultivation. 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. During
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#17328517502386014-425: 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. Famous rice paddies in China include the Longsheng Rice Terraces and the fields of Yuanyang County, Yunnan . India has the largest paddy output in the world and is also the largest exporter of rice in
6111-469: 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
6208-411: 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. 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
6305-419: 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 . It has also been introduced elsewhere since the colonial era, notably in northern Italy ,
6402-589: 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 . The spread of japonica rice cultivation and paddy field agriculture to Southeast Asia started with
6499-471: 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
6596-404: 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
6693-444: The field", "rice plant"). Cognates include Amis panay ; Tagalog pálay ; Kadazan Dusun paai ; Javanese pari ; and Chamorro faʻi , among others. 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
6790-405: The flesh is usually white and firm. Yellow yam has yellow flesh, caused by the presence of carotenoids. It looks similar to the white yam in outer appearance; its tuber skin is usually a bit firmer and less extensively grooved. The yellow yam has a longer period of vegetation and a shorter dormancy than white yam. The Kokoro variety is important in making dried yam chips. They are large plants;
6887-452: The fragile tubers; however, wood tools need frequent replacement. Yam harvesting is labor-intensive and physically demanding. Tuber harvesting involves standing, bending, squatting , and sometimes sitting on the ground depending on the size of mound, size of tuber, or depth of tuber penetration. Care must be taken to avoid damage to the tuber, because damaged tubers do not store well and spoil rapidly. Some farmers use staking and mixed cropping,
6984-447: The genus being toxic). Yams are perennial herbaceous vines native to Africa, Asia, and the Americas and cultivated for the consumption of their starchy tubers in many temperate and tropical regions. The tubers themselves, also called "yams", come in a variety of forms owing to numerous cultivars and related species. A monocot related to lilies and grasses, yams are vigorous herbaceous , perennially growing vines from
7081-605: The grated tuber, are used for bitter cultivars of this yam. The bitter compounds in yams also known locally as air potato include diosbulbin and possibly saponins , such as diosgenin . In Indonesia, an extract of air potato is used in the preparation of arrow poison. Raw yam has only moderate nutrient density , with appreciable content (10% or more of the Daily Value , DV) limited to potassium , vitamin B6 , manganese , thiamin , dietary fiber , and vitamin C (table). But raw yam has
7178-399: 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. The Hanja character for 'field', jeon ( Korean : 전 ; Hanja : 田 ),
7275-417: The highest potassium levels amongst the 10 major staple foods of the world ( see nutritional chart ). Yam supplies 118 calories per 100 grams. Yam generally has a lower glycemic index , about 54% of glucose per 150 gram serving, compared to potato products. The protein content and quality of roots and tubers is lower than other food staples, with the content of yam and potato being around 2% on
7372-504: The iced dessert called halo-halo . Purple yam desserts have more recently entered the United States through Philippine cuisine, under the Filipino name "ube". It is particularly popular due to the striking violet-purple color it gives to desserts. Purple yam is commonly confused with purple/violet varieties of sweet potatoes because of their similarities in color, taste, and culinary uses. However, like other yams, purple yam tends to have
7469-423: The introduction of cassava . D. rotundata , the white yam, and D. cayenensis , the yellow yam, are native to Africa. They are the most important cultivated yams. In the past, they were considered as two separate species, but most taxonomists now regard them as the same species. Over 200 varieties between them are cultivated. White yam tuber is roughly cylindrical in shape, the skin is smooth and brown, and
7566-404: The introduction of other crops, most notably the sweet potato . Purple yams have edible tubers which have a mildly sweet, earthy and nutty taste, reminiscent of sweet potatoes or taro . The violet cultivars, in particular, turn dishes distinctively vivid violet because of the high amount of anthocyanins . Purple yams are also valued for the starch that can be processed from them. Purple yam
7663-623: The land at various levels. 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
7760-558: 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. From about 2000 to 1500 BC, the Austronesian expansion began, with settlers from Taiwan moving south to migrate to Luzon in
7857-443: The next year. Yam crops face pressure from a range of insect pests and fungal and viral diseases, as well as nematodes . Their growth and dormant phases correspond respectively to the wet season and the dry season. For maximum yield, the yams require a humid tropical environment, with an annual rainfall over 1,500 millimetres (59 in) distributed uniformly throughout the growing season. White, yellow, and water yams typically produce
7954-419: 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
8051-619: The production of rice. It was for that reason, that people usually built their houses next to paddy fields. The very spicy chili pepper that is often eaten in Malaysia, the bird's eye chili , is locally called cili padi , literally "paddy chili". Some research pertaining to Rainfed lowland rice in Sarawak has been reported. Rice is grown in Myanmar primarily in three areas – the Irrawaddy Delta ,
8148-546: The question on whether D. alata is a true species or cultivated much older than believed. Purple yam remains an important crop in Southeast Asia, particularly in the Philippines where the vividly purple variety is widely used in various traditional and modern desserts. It also remains important in Melanesia , where it is also grown for ceremonial purposes tied to the size of the tubers at harvest time. Its importance in eastern Polynesia and New Zealand , however, has waned after
8245-505: The rainy season. The crop yield depends on how and where the sets are planted, sizes of mounds, interplant spacing, provision of stakes for the resultant plants, yam species, and tuber sizes desired at harvest. Small-scale farmers in West and Central Africa often intercrop yams with cereals and vegetables. The seed yams are perishable and bulky to transport. Farmers who do not buy new seed yams usually set aside up to 30% of their harvest for planting
8342-718: The regular use of iron tools, in the Three Kingdoms of Korea Period (c. AD 300/400-668). The first paddy fields in Japan date to the Early Yayoi period (300 BC – 250 AD). The Early Yayoi has been re-dated, 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. Although China's agricultural output
8439-524: The relative nutritional and antinutritional contents of each of these staples is remarkably different from that of raw form of these staples. raw yellow dent corn raw unenriched long-grain white rice raw hard red winter wheat raw potato with flesh and skin raw cassava raw green soybeans raw sweet potato raw sorghum raw yam raw plantains unofficial Paddy field A paddy field
8536-587: 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. In Nepal, rice (Nepali: धान, Dhaan) is grown in the Terai and hilly regions. It is mainly grown during the summer monsoon in Nepal . 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
8633-417: The round yam ( Dioscorea bulbifera ), ubi gadong ( Dioscorea hispida ), lesser yam ( Dioscorea esculenta ), Pacific yam ( Dioscorea nummularia ), fiveleaf yam ( Dioscorea pentaphylla ), and pencil yam ( Dioscorea transversa ). Among these, D. alata and D. esculenta were the only ones regularly cultivated and eaten, while the rest were usually considered as famine food due to their higher levels of
8730-603: The spread of rice cultivation throughout southern China. 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 . At Caoxieshan, a site of the Neolithic Majiabang culture , archaeologists excavated paddy fields. Some archaeologists claim that Caoxieshan may date to 4000–3000 BC. There is archaeological evidence that unhusked rice
8827-687: The threat from wild harvest has been successful. D. japonica – known as East Asian mountain yam, yamaimo, or Japanese mountain yam – is a type of yam (Dioscorea) native to Japan (including Ryukyu and Bonin Islands), Korea, China, Taiwan, and Assam. D. japonica is used for food. Jinenjo, also called the wild yam, is a related variety of Japanese yam that is used as an ingredient in soba noodles. Yams in West Africa are typically harvested by hand, using sticks, spades, or diggers. Wood-based tools are preferred to metallic tools as they are less likely to damage
8924-413: The toxin dioscorine which requires that they be prepared correctly before consumption. D. alata is also cultivated more than D. esculenta , largely because of its much larger tubers. D. alata and D. esculenta were the most suitable for long transport in Austronesian ships and were carried through all or most of the range of the Austronesian expansion . D. alata in particular were introduced into
9021-564: The tubers are fairly small in most varieties. The tubers are eaten baked, boiled, or fried much like potatoes. Because of the small size of the tubers, mechanical cultivation is possible, which along with its easy preparation and good flavor, could help the lesser yam to become more popular in the future. D. dumetorum , the bitter yam, is popular as a vegetable in parts of West Africa, in part because their cultivation requires less labor than other yams. The wild forms are very toxic and are sometimes used to poison animals when mixed with bait. It
9118-409: The vines can be as long as 10 to 12 m (33 to 39 ft). The tubers most often weigh about 2.5 to 5 kg (6 to 11 lb) each, but can weigh as much as 25 kg (55 lb). After 7 to 12 months' growth, the tubers are harvested. In Africa, most are pounded into a paste to make the traditional dish of "pounded yam", known as Iyan . D. alata , called purple yam (not to be confused with
9215-420: The world as of 2020. In India, West Bengal is the largest rice producing state. 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
9312-550: 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
9409-575: Was stored for the military and for burial with the deceased from the Neolithic period to the Han dynasty in China. 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
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