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Millennia of Silk Road exchanges shaped Chinese diet

WANG SIMING,LIU QIZHEN | 2017-07-12 | Hits:
(Chinese Social Sciences Today)


Zhang Qian, a Chinese official and diplomat in the Western Han Dynasty, was regarded as the pioneer of the ancient Silk Road and he traveled to the West Regions twice in his lifetime, bringing back dozens of new species of plants to the Han regime, which greatly enriched the Chinese agricultural system.

From ancient times until the Age of Exploration in the mid-15th century, the Silk Road and its sea-based counterpart served as China’s main channels for foreign exchange. One of the most important was agricultural exchange. While ancient China exported agricultural species, production technology and concepts of agronomy, it also incorporated foreign crops to enrich its own agricultural system.

A variety of foreign cultivars were introduced and successfully localized, increasing the diversity of crops and injecting momentum into ancient China’s agricultural development.


Imported crops
Material and cultural exchanges between China and the rest of the world started in prehistoric times. However, large-scale interactions and exchanges of crops started in the Western Han Dynasty (206 BCE-26 CE).

Today, 120 of the species still cultivated by China’s farmers originate from abroad. Prior to the Ming Dynasty (1368-1644), most of the crops introduced to China were from western Asia, while some came from the Mediterranean coast, Africa or India. Fruit trees and vegetables were the main imported products, but grains were rare.

A large number of foreign crops were brought to China mainly through diplomatic gifts from visiting envoys, business travel, trade or war. There were also other ways, such as ethnic migration and tourist travel.

After the mid-Tang Dynasty (618-907), China’s economic center began to shift from north to south, prompting the development of a parallel trade route on the sea and accelerating new agricultural species import. For example, Champa rice, a commonly cultivated quick-maturing, drought-resistant rice from India, was introduced to the southeastern coastal province of Fujian sometime between the Five Dynasties (907-960) and the early Northern Song Dynasty (960-1127).

The majority of foreign crops were introduced into China in the span of years between the Song (960-1279) and Qing (1616-1911) dynasties, and most of them were high-yield economic crops. During this time period, China’s agricultural layout was transformed while agricultural industries became increasingly diversified and commercialized.


Reshaping agricultural activities
In the pre-Qin period (prior to 221 BCE), China’s main grains were Setaria italica, or su in Mandarin, and a subspecies of Panicum miliaceum, known by the Chinese name shu. About 4,000 years ago, cultivated wheat was introduced to China from western Asia, and in the Tang Dynasty, it replaced Chinese millet as the most important cereal in the north.

Gradually, Chinese agriculture formed a pattern in which rice was the dominant grain in the south while wheat, millet and sorghum were the staples in the north. This structure continued until the Ming and Qing dynasties. The popularization of Champa rice in the Song Dynasty coupled with the introduction of corn, sweet potato, potato, pumpkin and other high-yield crops from the Americas in the Ming and Qing dynasties diversified and enriched the Chinese diet.

Ancient Chinese adopted multiple cropping, crop rotation, mixed cropping as well as intercropping and inter-planting systems to improve land utilization and prevent soil depletion. The introduction of foreign species greatly enriched the content of ancient cropping and inter-planting.

In the Han Dynasty, farmers on the fertile Yellow River basins developed a three-crop system of rotation, and in the Tang Dynasty, those living in the Yangtze River Valley established a two-crop system of alternating rice and wheat.

The practice was codified in the sixth-century Chinese agricultural manual Qimin Yaoshu, or “Essential Techniques for the Welfare of the People,” which instructed farmers to grow grains and mung beans in rotation.

During the Ming-Qing period, China’s population grew rapidly relative to the amount of arable land, posing a challenge for agricultural sustainability. The Columbian Exchange, the exchange of plant spieces from the Americas, brought versatile, high-yield crops that could be cultivated on barren, hilly or muddy land, thus increasing the area and yield of grain production. In a way, exotic crops further improved the level of intensive management of traditional agriculture.

Since modern times, the main crops for cotton intercropping in northern China include sweet potato, watermelon, melon and sunflower. In the southwest, a variety of intercropping patterns are popular, such as rape and sweet potato, corn and peanut, and corn and chili. In southern China, farmers frequently rotate cotton with corn or sweet potatoes.

In particular, the cultivation area of peanuts was largely expanded in the Ming-Qing era and the ancient Chinese adopted crop rotation and intercropping to improve yield, which differentiated China from other peanut growing countries.

What’s more, ancient Chinese agriculture had a long tradition of accumulating and apply organic fertilizer, which was another secret of keeping the farmland fertile. There are many kinds of organic fertilizers, including the rhizome of crops.

Corn stalks were widely used and green plants were also an important source of organic fertilizer. Peas, cowpeas, broad bean, eyebrow beans and other exotic leguminous plants were fine sources of fertilizer. Though peanuts were not specialized manure, peanut seedlings can also be used as high-quality green manure, as recorded in the Qing Dynasty agricultural texts.


Enriching traditional diet
According to historical records, there were 21 kinds of vegetables in the Han Dynasty, 35 in the Northern and Southern Dynasties (420-589), and 176 in the Qing era. The arrival of exotic vegetables made up for the limited vegetable varieties, and the Chinese diet began to favor melons, eggplant, leafy vegetables and beans.

Prior to the Ming Dynasty, there was no chili in China and people used prickly ash and zanthoxylum ailanthoides for spice. At first, the brightly colored imported chili peppers were used for decoration. Not until later did people find that chilis had the effect of warming the stomach and spleen, detoxification and antimicrobial properties, and eventually it was cultivated as a vegetable on a large scale.

In the mid-18th century, the development of chili peppers was particularly stunning. In the upper and middle reaches of the Yangtze River, and some southwest, northwest provinces, chili peppers became a must-have vegetable. Cooking methods were also diversified: Chilies could be consumed raw, fried, dried, pickled and sauced. The same goes for tomatoes, pumpkins, zucchini and winter squash, which all became popular among the Chinese during different periods of time.

In pre-Qin times, grapes were grown in the Western Regions and were introduced to the Central Plains in the Western Han Dynasty. In the Tang Dynasty, grape cultivation was extremely popular, and different grape varieties were known to the Chinese. Delicious and nutritious, grapes quickly became one of China’s favorite fruits.

Before the Han Dynasty, animal fat was the dominant form of cooking oil while vegetable oil was scarcely produced due to lack of plants with high oil content. The only domestically cultivated oil-producing plants were hempseed and perilla, which provided early sources of vegetable oil in China.

However, given the low oil yield of existing vegetable varieties, people still preferred animal oil, such as lard. Sesame seeds, which were introduced sometime between the first and fifth century, offered an alternative. Thanks to its flavor and high yield, sesame oil quickly became the most important vegetable oil. The monopoly of sesame oil was not broken until the Song Dynasty when rape and soybean oil were extracted.

Later in the Ming-Qing era, peanut and sunflower were added for oil production, which further enriched Chinese edible oil varieties. At this time, China’s main oil-bearing crops were soybeans, rapeseed, peanuts, sesame and sunflower, three of which were foreign imports. Therefore, it is safe to say that foreign crops were crucial to China’s cooking oil production.


Changing daily life
Foreign agricultural commodities, including economic crops, vegetables and fruits, were brought to China along the Silk Road, meeting the diverse needs of the Chinese. The population boom in ancient regimes caused robust demand for agricultural products, so these imported crops not only enriched the lives of people but also played a positive role in raising farmers’ incomes.
For much of Chinese history, silk, hemp, poplin and wool were primarily used to make clothes, but linen was the norm. During the Song and Yuan (1206-1368) dynasties, cotton was introduced to the hinterland from frontier regions. Compared to silk and hemp, cotton had an obvious advantage. Cotton soon broke the monopoly of silk and hemp clothing and became the main material for Chinese costumes in the Ming Dynasty. To this day, cotton is still an important clothing material.

China has a long history of brewing and drinking liquor. Ancient Chinese used to make liquor out of millet, rice and other grains. Later, sorghum, wheat, barley, corn, coix and other foreign crops also became the important ingredients of Chinese liquor. Among them, sorghum was the best raw material for brewing liquor, and wheat was the most ideal raw material for making wheat koji.

Exotic tubers, such as sweet potatoes, cassava and potatoes, and legumes, such as mung beans and peas, played an increasingly important role in the traditional Chinese liquor industry. Many imported fruits, such as grapes, pomegranates, and watermelon were used to brew wine, too.

In short, a variety of foreign crops came to China through the land and sea trade routes, greatly enriching the local species; promoting industries, such as planting, horticulture and aquaculture, and adjusting and optimizing clothing structure. To say the least, they were crucial to the prosperity of the traditional social economy and the development of Chinese agricultural civilization.


Wang Siming and Liu Qizhen are from Nanjing Agricultural University.