Wild potatoes are native to the Andes in South America and are planted by local Indians. Spanish colonists brought it to Europe in the16th century. 1586, the British defeated the Spanish in the Caribbean, collected tobacco and other plant seeds from South America, and brought potatoes to Britain. The climate in Britain is suitable for potatoes, which are taller and easier to manage than other grains. 1650, potatoes have become the main food crops in Ireland, and began to spread in Europe. 1719 was brought back to the United States by Irish immigrants in the 7th century and began to be planted in the United States.

1840, a potato epidemic broke out in Europe, and Ireland, which was completely dependent on potatoes, suffered the most and faced a great famine. Nearly one million people starved to death and millions of immigrants fled to the United States.

In17th century, potatoes had spread to China. Because potatoes are very suitable for planting in cold areas where the original grain yield is extremely low and only naked oats can be planted, they quickly spread in Inner Mongolia, Hebei, Shanxi, northwestern Shaanxi and other places. High-yield crops such as potatoes, corn and sweet potatoes imported from the United States have become the main food for the poor and played an important role in maintaining the rapid population growth in China.

Corn (also known as corn; Known as Xiaomi in Cantonese and Fanmai in Taiwanese, it is an annual herbaceous gramineous plant. Native to Central America, it is the main food crop cultivated by Indians and likes high temperature. It was introduced to China in17th century. Due to the suitable climate and high yield, it quickly spread, mainly distributed in the mountainous areas in the north and southwest of China, and soon replaced the original main food crop millet in these areas. Because its growing period is interlaced with winter wheat, it can be rotated with winter wheat in the northern region near the Yellow River basin with a long frost-free period, thus increasing the grain yield and becoming the main grain for the lower population, which is one of the main reasons for the rapid population growth in China after18th century. Apart from the United States, China is the most popular corn growing area. Corn is also the tallest grain in the world. Introduction and popularization of maize

The original name of maize is maize, and there are many common names in various places, such as Fanmai, Yumai, Maize, Baogu, Lu Bao, Pengzi and pearl rice. It is also called Liugu, which means another kind of valley besides grains.

Corn is native to America. Some people talk about corn according to Jia Ming's Diet Notes in the Yuan Dynasty (around 1367), and the Commercial Grain Bureau in the Yuan Dynasty (a specialized institution for the imperial court to manage the diet in the Yuan Dynasty) has royal wheat flour, thinking that there was corn in China in the Yuan Dynasty. This statement may not be correct. The so-called royal wheat flour is just the best wheat flour used by autocratic emperors. The part about corn in the Dietary Guide is probably added by later generations, which is not very reliable. For a long time, corn has been the main food crop of Native Americans. There are many stories about corn, and a large number of ancient corn seeds and corn gods made of gold, soil and corn ears have been excavated underground. In the history of other countries, until the fifteenth century, no country had any records or signs about corn. So you can say that. It was after Columbus discovered America in 1492 that corn spread to the countries of the old world.

Western scholars have different theories about how corn was introduced into China. Some people think that corn is brought by Arabs from Spain to Mecca, from Mecca to Central Asia to the northwest of China, or from Mecca to Muslim India to the southwest of China, and then spread to the provinces from northwest or southwest to east. This speculation needs further study. The early China literature they quoted was generally limited to the Ming Dynasty.

Li Shizhen's Compendium of Materia Medica (1578), and some of them are just quoted from-Heng's "Youth Day Zagreb" (1573). In fact, there are abundant records about corn in the county annals of China's provincial capitals.

According to local chronicles and county records of various provinces, corn was first introduced to China in Guangxi at the time of 153 1 year, less than 40 years after Columbus discovered America. By the end of the Ming Dynasty (1643), it had spread to ten provinces including Hebei, Shandong, Henan, Shaanxi, Gansu, Jiangsu, Anhui, Guangdong, Guangxi and Yunnan. There are Zhejiang and Fujian provinces. Although it is not recorded in the local chronicles of the Ming Dynasty, there are other documents that prove that corn was planted in the Ming Dynasty. During the fifty years of the early Qing Dynasty, until the end of the seventeenth century (that is, the thirty-ninth year of Kangxi), there were more records about corn in the local chronicles of Liaoning, Shanxi, Jiangxi, Hunan, Hubei, Sichuan and other provinces than in the Ming Dynasty. After 170 1 year, there were more records of maize, and by 17 18, Taiwan Province Province and Guizhou Province were added. According to records, in less than 200 years from 153 1 to 17 18, corn has spread all over 20 provinces in China.

We look at the earliest literature records in each province in chronological order: Guangxi 153 1 year, Henan 1544, Jiangsu 1559, Gansu 1560, Yunnan 1563. Shandong 1590, Shaanxi 1597, Hebei 1622, Hubei 1669, Shanxi 1672, Jiangxi 1673, Liaoning1. The above chronological order does not represent the order of actual introduction, because there are often omissions and late entries in local chronicles and other documents. However, it is worth noting that the record of Guangxi is about 30 years earlier than that of Gansu or Yunnan, more than 60 years earlier than that of Shaanxi, more than one and a half centuries earlier than that of Sichuan and almost two centuries earlier than that of Guizhou. In addition, Jiangsu is earlier than Gansu and Yunnan, and Zhejiang, Fujian and Guangdong are 20 years or even more than a century earlier than Shaanxi, Sichuan and Guizhou. It is hard to imagine that corn first spread to the southwest or northwest of China by land, and then spread to the east. On the other hand, the Portuguese arrived in Java in 1496 and in China in 15 16. At the same time, there were many China people living in Nanyang Islands at that time, so it was very possible for corn to be introduced into China's coastal and offshore provinces by sea.

Both corn and sweet potato originated in America, and they became important food crops in China in one or two hundred years after they were introduced to China, but there were obviously different phenomena in the process of spreading. There are many touching stories about the spread of sweet potatoes, but not about corn. From the very beginning, sweet potato attracted the special attention of the famous agronomist Xu Guangqi, and strongly advocated it. In his book On Agriculture and Politics, he elaborated on the methods of cultivating sweet potatoes. As for corn, only the note under the sorghum strip reads: "You can get other seeds if you cover it", and there is no mention of its cultivation method and its importance. Although there are many records about corn in local chronicles, they are generally very simple. Most of them only mention that there is corn in the product, or describe some different names and characteristics of corn, and there are few records about propaganda and its importance. In a word, corn has not received the attention of intellectuals like sweet potato. Nevertheless, corn was introduced into China in obscurity, half a century earlier than sweet potato. In the late Ming Dynasty, corn had spread to twelve provinces, while sweet potato only had four provinces.

This phenomenon reflects a very important fact: the introduction and popularization of new crops mainly rely on the trial planting and expansion of production by farmers. People benefit from hard-working farmers, and once they see that corn is a high-yield crop suitable for dry land and mountainous areas, it is quickly absorbed and utilized. For example, "Anhui Huoshan County Records" (Qianlong 4 1, 1776) said: "Forty years ago, people accidentally planted only one or two trees in the garden for their children to eat, but now it is all over the mountains, 200 miles southwest, all for food." Another example is the county annals of Zunhua, Hebei Province (Guangxu 12, 1886), which records that during the Jiaqing period (1796- 1820), someone brought some corn seeds from Shanxi to Zunhua, and at first they were planted in the garden, but in the Guangxu period (65430). China has a fine tradition of intensive cultivation, and its agricultural technology has reached a fairly high level. Therefore, after introduction, we can quickly master and improve the cultivation techniques according to the characteristics of crops and local conditions, cultivate many varieties suitable for the local area, and create a variety of edible methods. The rapid development of corn was after the second half of the eighteenth century. At present, it is cultivated in all provinces and regions of the country, and its output far exceeds that of millet, often second only to wheat, ranking third in food crops.

Wild potatoes are native to the Andes in South America and are planted by local Indians. Spanish colonists brought it to Europe in the16th century. 1586, the British defeated the Spanish in the Caribbean, collected tobacco and other plant seeds from South America, and brought potatoes to Britain. The climate in Britain is suitable for potatoes, which are taller and easier to manage than other grains. 1650, potatoes have become the main food crops in Ireland, and began to spread in Europe. 1719 was brought back to the United States by Irish immigrants in the 7th century and began to be planted in the United States.

1840, a potato epidemic broke out in Europe, and Ireland, which was completely dependent on potatoes, suffered the most and faced a great famine. Nearly one million people starved to death and millions of immigrants fled to the United States.

In17th century, potatoes had spread to China. Because potatoes are very suitable for planting in cold areas where the original grain yield is extremely low and only naked oats can be planted, they quickly spread in Inner Mongolia, Hebei, Shanxi, northwestern Shaanxi and other places. High-yield crops such as potatoes, corn and sweet potatoes imported from the United States have become the main food for the poor and played an important role in maintaining the rapid population growth in China.