Paddy Field 3d Model !FULL! Free Download
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Current estimates of China's ammonia (NH3) volatilization from paddy rice differ by more than twofold, mainly due to inappropriate application of chamber-based measurements and improper assumptions within process-based models. Here, we improved the Jayaweera-Mikkelsen (JM) model through multiplying the concentration of aqueous NH3 in ponded water by an activity coefficient that was determined based on high-frequency flux observations at Jingzhou station in Central China. We found that the improved JM model could reproduce the dynamics of observed NH3 flux (R2 = 0.83, n = 228, P < 0.001), while the original JM model without the consideration of activity of aqueous NH3 overstated NH3 flux by 54% during the periods of fertilization and pesticide application. The validity of the improved JM model was supported by a mass-balance-based indirect estimate at Jingzhou station and the independent flux observations from the other five stations across China. The NH3 volatilization losses that were further simulated by the improved JM model forced by actual wind speed were in general a half less than previous chamber-based estimates at six stations. Difference in wind speed between the inside and outside of the chamber and insufficient sampling frequency were identified as the primary and secondary causes for the overestimation in chamber-based estimations, respectively. Together, our findings suggest that an in-depth understanding of NH3 transfer process and its robust representation in models are critical for developing regional emission inventories and practical mitigation strategies of NH3.
A paddy field 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, Southeast Asia including Northeastern India, 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, Northeast India, Indonesia, Northern Iran, Japan, Laos, Malaysia, Myanmar, Nepal, North Korea, Pakistan, the Philippines, South Korea, Sri Lanka, Thailand, Taiwan, 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.
The word "paddy" is derived from the Malay 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]
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.[5][6]
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.[7][8][9][10][11] The second is in the middle Yangtze River, believed to be the homelands of the early Hmong-Mien speakers and associated with the Pengtoushan, Nanmuyuan, Liulinxi, Daxi, Qujialing, and Shijiahe cultures. 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.[8][9][11]
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.[18][19]
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.[9]
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.[9]
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.[26][27]
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.[36] 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.
Rice is grown in Northern Italy, especially in the valley of the Po River.[38] 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 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."
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.
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