Rice production in China

Rice production in China
Japonica plant Wheat
Uses	To make rice

Rice terraces in Yunnan, China

Rice production in China is the world's largest producer of rice, making up 30% of global rice production, making up an important part of the national economy. It produces the highest rice yields in Asia, at 6.5 metric tons per hectare (2.6 long tons per acre; 2.9 short tons per acre). Rice is produced throughout the nation and is believed to have been domesticated around the Yangtze River Valley and Yellow River from 7000 BC. The main variants of rice grown in China are indica and japonica subspecies, with ongoing developments in hybrid rice. Rice cultivation is labour-intensive, and is dependent on a variety of cropping and planting methods, as well as fertiliser and pesticides. Rice is highly prized by consumers as a food grain, making it a staple food for two-thirds of the nation.

History

Wild rice and its domestication

China is among the bulk of significant domestication centres and originating rice regions worldwide. The surrounding regions of the Yangtze River and the Yunnan-Guizhou highland of Southern China are the domestication centres with varying evidence derived from the belief that wild rice is primarily found in Southern China, where the Yangtze River is predominantly situated. China's Yunnan-Guizhou highland consists of more than 10,000 rice landraces, and the three wild rice species (O. Rufipogon, O. Officinalis, and O. Mereriana) commonly exist and is identified as the site of the highest genetic diversity.  Over time, these varieties evolved under environmental and cropping conditions into O. Sativa and the subspecies of japonica and indica consumed today. Additionally, as more rice phytoliths are detected in sites of Hemudu, Diaotonghuan, Xianrendong, and Shangshan – all parts surrounding the Yangtze River, it is these regions that are of the geographical domestication origin of wild rice in China.

According to archaeological records, rice was first domesticated in areas surrounding the Yangtze River Valley and the Yellow River around 7000 BC. These areas housed Neolithic sites like Hemudu (6800-5000 BC), Luojiajiao (5100-4000 BC), Caoxieshan (4200-3900 BC) and Songze (circa 4000 BC). Older rice remains have been found in Yuchanyan (13000-6000 BC), Xianrendong and Diaotonghuan (12000-9000 BC).

The domestication of rice was observed through the loss of colour and seed shattering, lower rates of seed dormancy and changes in seed shape. Cultivated forms of phuddi rice are of domestic origin, whilst indica rice appear to be of mixed origin, via domestication throughout South and Southeast Asia.

Paddy field in south-western in Yunnan

Wild rice in China is believed to have been harvested by individuals over millennia and then transitioned into domesticated rice. Early farmers employed fire, bones and wooden spades to clear marshes of reeds in order to establish rice paddy fields.

Rice cultivation

Rice has been cultivated in China for over 10000 years. The first record of rice has been linked to mythological texts such as Guan Zi from the Shen-Nong era, part of the Xia dynasty in the 21st century BC. In antiquity, japonica rice was named Jing or Keng, indica rice was named Xian or Hsien, whilst glutinous rice was named Nuodao.

As modern researchers uncover archaeological records of rice, it is revealed that rice was first cultivated within the middle of the Yangtze River in central China. Archaeological evidence in this finding drew upon collecting “samples of radiocarbon data on rice grains, husks, plant remains, and impressions of rice grain in pottery drawn from more than one hundred sites along the 6300-kilometre Yangtze River.”  The oldest sample collected comprised a median age of 11,000 years, found upon clustering in the middle of the Yangtze River in the provinces of Hubei and Hunan in central China.  In comparison, samples collected from the upstream and downstream regions are ordinarily younger, ranging from 4000 to 10,000 years.  Researchers uncovered this pattern, suggesting that rice cultivation originated in the middle of the Yangtze River and has since spread from there.

Planting techniques

Techniques such as turning soil into mud to prevent water loss, as well as seed transplantation have been traced back to China. Both techniques encouraged the domestication of phuddi and indica variants, and are still utilised in Chinese rice production today.

Rice variants

Wild rice

There are three species of wild rice in China, O. mereriana, O. officinalis and O. rufipogon. The last is the most common, spanning from Taiwan and across China. Wild rice is commonly found in marshlands, hills and low grasslands. Archaeological records note common variants of wild rice were planted in Central and Southern China in antiquity. Due to increased human activity over the years, there has been a 70% decrease of O. rufipogon across China compared to the 1950s.

Chinese cultivated varieties

Cultivated varieties are noted to have originated in areas near the Yangtze and Huai rivers. From these areas, wild, ancient varieties spread through environmental and cropping conditions. Over time, these varieties evolved and were domesticated into O. sativa subspecies japonica and indica.

Rice breeding

Hybrid rice breeding seeks to improve yield and adaptation in response to demand and environmental challenges and was introduced in the 1970s by Yuan Longping. In 1996, the Super Rice Project was spearheaded by the Ministry of Agriculture, combining japonica and indica subspecies. However, this breeding process is time-consuming and has affected the growth of the breeding program and available rice variants.

Subspecies throughout the regions

Japonica grains

Japonica

Japonica plants are small and have dark green leaves. Its grains are round and short and do not break easily. Due to its high levels of amylopectin, grains are moist and sticky when cooked. Japonica is found in cool and temperate climates.

Indica

Indica plants are tall and have light green leaves. Its grains can range from short to long, narrow and flat, and can break easily. Due to its lower levels of amylopectin, grains are flakier and drier than japonica variants.

Subspecies and their growing regions

• Japonica subspecies are predominant throughout Regions 2, 3, 5 and 6.
• Indica subspecies are predominant throughout Regions 1, 2, 3 and 4
• Hybrid variants of Indica are grown in Region 2.

Geographical setting

Growing regions

Region 1: Southern China

This region includes southern areas of Guizhou, Guandong, Guangxi and Fujian and Hainan provinces as well as Taiwan. This region is subtropical and predominantly grows indica rice.

Region 2: Central China

The largest region in terms of rice production, spanning from the Chengdu Plains in the west to the eastern coast, from the Huai River in the north to the Nanling Mountains in the south. It also includes parts or all of Hubei, Hunan, Jiangxi, Anhui, Zhejiang, Jiangsu provinces and suburbs of Chongqing and Shanghai. This region is subtropical and predominantly grows Indica, hybrid variants of indica and japonica rice.

Region 3: Southwestern plateau

Includes parts or all of Tibet, Sichuan, Qinghai, Yunnan, Guangxi, Hunan, Guizhou provinces as well as the Qingzang and Yungui Plateaus. This region is subtropical and predominantly grows japonica and indica rice.

Region 4: Northern China

Bordered by the Qinling Mountains, the Yellow River in the south, the Great Wall in the north, and bordered in the west by the Shaanxi Plains. It also includes the entirety of Beijing, Shandong and Tianjin, and parts of Anhui, Shaanxi, Jiangsu, Shanxi, Henan and Hebei provinces. This region is subtropical and predominantly grows indica rice.

Region 5: Northeastern China

Includes Jinlin and Heilongjiang, as well as Liaoning and Inner Mongolia. This region has the coldest climate out of all the growing regions, with temperatures averaging between 2 to 10 °C (36 to 50 °F). It predominantly grows indica rice

Region 6: Northwestern China

Includes Ningxia and Xinjiang, most of Inner Mongolia and Gansu, north-western sections of Liaoning as well as northern sections of Shaanxi, Qinghai and Hebei provinces. This is the driest out of all the regions and predominantly grows japonica rice.

Climate, growing periods and soils

Subtropical

This climate is characterised by humidity and warm monsoons, long periods of growth between 180 and 365 days, cumulative temperatures between 2900 and 800 °C, precipitation levels between 580 and 3,000 mm (23 and 118 in) and 700–3000 hours of sunshine. Soil types within these regions include brown, red and yellow soils as well as sedimentary and alluvial soils.

Cold

Crops are susceptible to frost damage. Its cumulative temperature ranges between 2000 and 3700 °C, 350-1100mm of precipitation and 2200–3100 hours of sunshine. Soils in this region are fertile, which include variants such as meadow, down, black clod and saline-alkaline soils.

Dry

Low rates (150 to 200 mm [5.9 to 7.9 in]) of precipitation and water shortages. Due to this, soils lack fertility and are situated near irrigated farms and rivers.

Growing seasons

Early rice crops grow primarily in provinces along the Yangtze River and in provinces in the south, it is planted in February to April and harvested in June and July. Intermediate and single-crop late rice grows in the southwest and along the Yangtze, it is planted in March to June and harvested in October and November. All three crop types contribute about 34 percent to China's total rice output. Double-crop late rice, planted after the early crop is reaped, is harvested in October to November and adds about 25 percent to total rice production. Rice grown in the north is planted from April to June and harvested from September to October, it contributes about 7 percent to total production. As the climate becomes warmer, it becomes possible for rice cultivation to advance further north.

Regional rates of rice production in China (2019)

Production

Farmer plowing rice paddy field with a water buffalo

Processes

Cropping systems

Cropping systems vary across China due to differences in climate in each growing region. Single rice cropping is predominant in the North, accounting for 17% of the country's total rice production. Double rice cropping is mainly utilised in the South, accounting for 34% of the country's production rate. Whilst annual rice-upland crop rotation systems are commonly used in Central regions such as Hubei, Sichuan, Anhui and Jiangsu provinces, as well as near the Yangtze River Valley. Rice-upland systems generate 49% of the nation's rice production.

Planting methods

Planting methods depend on the environmental and socioeconomic conditions of a growing region. Common methods of planting include manual, throwing, mechanical, direct seeding (manual and mechanic) and ratooning rice. Manual transplanting is declining in rural areas due to lack of skilled labour, it is common in areas with smaller land areas, high populations and higher rates of available labour. Direct-seeded rice (dry and wet seeding) has increased since the 1990s, taking up 10% of China's rice planting area in provinces such as Guandong and Xinjian.

Transplanting is China's most common and elaborative rice crop establishment and production method. Transplanting is often done to achieve higher yields and more minor weeding fields, whilst ensuring a uniform rice plant stand.  Transplanting is where rice seedlings grown in a nursery are harvested and transplanted into puddled and levelled rice fields 15 to 20 days after the seedling,  some even for an extended incubation period. These rice seedlings can either be transplanted manually or mechanically.

Manual transplanting is a traditional rice production method across China. Manual transplantation does not require costly machinery and is often performed in minor rice patch fields in labour surplus. Manual transplanting is often performed in rice patch fields with substandard levelling and varying water levels.  Seedlings by this method can be raised and adapted under any condition, whether wet, dry, or modified.  Given the adaptability flexibility of seedlings, manual transplanting tends to increase yields significantly in low fertility soils.

Mechanical transplantation of rice is transplanting young rice seedlings using a rice transplanter. As the name suggests, direct seeding is the process of sowing rice seeds directly into the rice fields, either mechanically or manually.  Both mechanical transplantation and direct seeding of rice are pioneering rice planting methods and are commonly used during the rice-wheat rotation system. The convenience of direct seeding and mechanical transplanting method can be manifested in the rice planting area of the Jiangsu Province in China, which comprises 2.249 million hectares of land, encapsulating 55.9% of fields that use these methods interchangeably.  These two methods increase yearly due to labour and time-saving reasons and quickly and cost-effectively provide area revegetation.

Throwing seedlings is an alternative planting method for rice production and is widespread due to savings on labour. This cultivation system provides another benefit of developing high-yield potential from reduced fertiliser inputs predominantly used over the past few decades in Southern China to raise yields, as was tested by scientists in Southern China rice patches along the Yangtze River. The method of the experiment is through an “appropriate increase in seedling density, and a concomitant decrease in Nitrogen fertiliser input” that led to “problems with lodging, quality declines, and environmental pollution”. By increasing the seedling density by 32%, Nitrogen application can reduce by 18%.  As a result, an increase in seedling density created considerable amounts of effective panicles and glumous flowers on rice wheat whilst compensating for the decreased yield of individual plants from fertiliser. Hence, the method and experiment provide sustainable agriculture means in Southern China.

Rice production in China is severely constrained by “excessive water consumption, labour shortage, large environmental footprint, and low economic profit” – this makes rice ratooning a favourable practice for production. From the former, rice ratooning is acquiring new crops from renewed tillers of the first crop, saving water consumption by taking advantage of the remaining water content from the first crop. From the latter, rice ratooning increases farmers’ profitability with sustainable efficiency and fewer reconstruction efforts on environmental damage and footprints than other rice planting methods. In addition, rice ratooning provides higher grain yield stemming from selecting cultivated high-yielding varieties and improving crop management over time. Hence, rice ratooning gradually became favourable and forms the majority of the rice production system across China.

Quality

There are differences and changes in the selection of rice varieties and cultivation techniques under various planting methods. Therefore, selecting good-quality rice is "necessary to promote the development of high-quality rice industry and enhance the rice industry's comprehensive strength in China."

Rice quality comes from processing, appearance, consumption, and essential nutritional quality. Therefore, the formation of rice quality stems from a range of aftermath processing factors and not only from the inherent characteristics of the different varieties of rice grains.  However, factors in the natural environment in rice production regions, such as soil conditions, weather conditions, techniques and methods used in cultivation, rice grains purifying conditions, and storage conditions, also influence quality.

Given the factors in the natural environment influencing quality, the focus of temperature and weather conditions have been predominantly studied by researchers in China from the China National Rice Research Institute. It has been demonstrated that the temperature during the grain-filling stage is crucial and affects the chalkiness quality of grains. Rice filled under high temperatures increases chalkiness, which is considered an undesirable feature due to the adverse effects on rice's appearance and milling quality.

Different rice planting methods in different regions across China with variances in times of dissemination, fertilization, and water resources also affect rice quality. This is because the methods used have variances in temperature and light resources during the final stage of rice growth. Moreover, researchers in the China National Rice Research Institute conducted studies in rice fields have found that an increase in potassium fertilizer used to improve root growth, plant vigour, lodging prevention, and enhance crop resistance to pests could reduce the chalkiness and improves rice quality, but have adverse effects on human consumption.

Changes to planting areas

There have been dramatic increases and decreases in arable land and production across China. Increases were found in Northeast provinces such as Jilin and Heilonjiang, whilst increasingly urbanised provinces such as Guandong and Fujian saw decreases. This is due to more farmers and their families looking for a stable occupation in urban areas. As well as challenges to production due to climate change and lower grain production due to over-usage of fertilisers and pesticides. Consequently, prominent rice production areas have shifted to the northeast.

Exports

International rates of rice exports (2019)

In 2019, China exported 4.56% of the world's rice with a value of US$1.13 billion. In 2020/2021, it is the sixth principal rice exporter in the world behind India, Vietnam, Thailand, Pakistan and the United States.

In the period of November 2020 and November 2021, China's Rice exports accounted for up to $75 million and imports that accounted for up to $202 million. It was a year that particularly resulted in a negative trade balance of $127 million.

In November 2021, the Rice were mainly exported to Turkey that accounted for $11.1 million, South Korean, accounting for $9.54 million, Vietnam, accounting for $7.49 million, Cameroon for $7.39 million, and Puerto Rico, making up of $7.1M.

Imports were mainly from Thailand of $44.4 million, Vietnam for $40.9 million, Pakistan for $34 million, India for $31.5 million, and Myanmar for $30 million.

Challenges

Climate change

Climate change has brought about increased frequencies of natural disasters such as floods and droughts. For rice crops, this does not generate grain growth, leading to decreased yields.  In 2003, crops in the province of Hubei experienced a 0.5-million-hectare loss due to rice crops experiencing heat stress. Grains remain empty in temperatures over 35 °C (95 °F). During the same period, Hubei lost 0.27 million hectares to low rates of rice grain production.

Overuse of fertilisers

China consumes 30% of the world's nitrogen fertilisers, 7% of this is employed for Chinese rice crops. Despite its excessive use, China's yield rates are comparably lower than other rice-growing nations who also utilise nitrogen fertilisers. Low amounts of fertiliser, around 20-30% is absorbed by a plant, whilst the remaining amount pollutes surrounding ecosystems leading to soil infertility.

Overuse of pesticides

Chinese rice farmers are known to spray their crops on a weekly basis to avoid damage by pests and diseases. Increased pesticide use has been linked to the overuse of nitrogen fertilisers and pesticides, which promotes changes in biodiversity and therefore increased pest outbreaks. Crop losses for pesticide-treated crops were double that of non-pesticide-treated crops. Farmers have been reported to experience negative health effects on their nervous, digestive and respiratory systems, leading to chronic diseases and deaths.

The future of Chinese rice production

Elite germaplasm, genetic diversity and the super rice breeding program

The creation of elite germaplasms such as the indica-japonica hybrid has encouraged for the research and development of new variants through studying elite genes and hybrid options. This, alongside the established super rice breeding program, researchers aim to produce high quality rice which is tolerant to drought and grain infertility.

Integrated rice cultivation systems

Further developments have been made with the assistance of agriculture systems and databases to manage fertilisation, irrigation, field management, disease and pest management, as well as predictions to estimate rice yields.

Lowering water-usage

Aerobic rice utilises low rates of water due to its ability to grow in high altitudes. Studies are investigating its high tolerance to drought and low irrigation, in order to develop variants for rice fields in Northern and Central China with inadequate irrigation.

Consumption

Nian gao

Due to the abundance of rice grown within China, it is considered as a staple food for two-thirds of the nation. Over 149 million metric tons were consumed in 2020/2021, with an average of 76.8 kilograms milled per person annually.  However, there has been a pattern of a decline in rice consumption, from 78 kilograms per person annually in 1995 to 76.3 kilograms in 2009.  

It is prepared and consumed in a range of forms, these include:

Cooked rice

Milled rice cooked with water by boiling, steaming and braising. Rice can be flavoured by adding vegetables, meat, fish and legumes. Rice porridge is a popular dish for individuals with health issues and children, as it is easy to digest.

Chinese white rice wine

Noodles and milled rice delicacies

Milled rice can be ground and processed into rice noodles, dumplings such as Tangyuan, Zongzi and Yuanxiao, glutinous rice cakes such as Nian gao, Maqiu, puddings, crackers, bread and fermented food. Ground rice can range in colour when made out of red, purple and brown types of rice.

Alcoholic beverages

Rice can be used as a base for alcoholic drinks such as rice wine like Jiafan and Nuerhong, both made out of japonica glutinous rice. Sweet rice wines are usually homemade and are made out of japonica or indica glutinous rice.

Rice bran

Rice bran is made out of the by-products of rice milling and is used as a cooking oil due to its high levels of oil, vitamin and protein.

References

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