On May 15, Yongping Mansion hurriedly came to a group headed by Xu Guangqi, the left attendant of the Ministry of Rites.

This Xu Guangqi is not an ordinary person, he is a famous expert in the fields of Confucianism, Western studies, astronomy, mathematics, water conservancy, agriculture, and military science in the late Ming Dynasty.

He was unanimously recognized by later generations as a scientist, thinker, politician, and military strategist, and he was also a devout Catholic leader and apologist, and was hailed as the first person in China to open his eyes to the world.

He translated and vigorously promoted Western scientific classics such as "Principles of Geometry", and the terms such as points, lines, planes, right angles, and quadrilaterals were all derived from him. Even the place name of Shanghai, Xujiahui, originated from him.

He was supposed to be a member of the Donglin Party, but now he is certainly not, because according to Catholic teachings, a devout believer should be pure and cannot join a party, even the one of Wei Guangzheng.

Xu Guangqi's scientific achievements are reflected in many fields, but mainly agricultural science runs through everything, because his good wish is to make the world "rich in food and clothing, and free from hunger and cold".

Jiannu plagued the land of Gyeonggi, resulting in the longest occupation by the Later Jin Army, and more than half of the acres of land in the Yongping Prefecture area of half a year missed the agricultural time.

He is already in his early sixties, he is old and strong, in the year of the apocalypse, he in Liangxiang, Tianjin and other places to carry out experimental fields to try to grow sweet potatoes, he used cellar insulation technology, successfully introduced this high-yield crop that was originally only planted in the south to the cold north, and the result was a bumper harvest.

He found that the agricultural planting level of the people in the north was not high, and the grain output was seriously insufficient, so he reclaimed canals and experimental fields in the Fangshan and Laishui areas, and through various experiments, finally succeeded in introducing more high-yield grain crops in this area, rice.

After Wei Zhongxian monopolized the government, he wantonly framed the Donglin Party, although Xu Guangqi was no longer a party member and hated the scum of the Donglin Party playing in the nest, but sympathized with Donglin gentlemen such as Yang Lian and Zuo Guangdou.

He disdained to bend his eyebrows and bend his waist to the powerful, so he simply retired to his hometown, continued his agricultural experiments in Songjiang Prefecture, and finally compiled and completed his epoch-making scientific masterpiece "The Complete Book of Agricultural Administration".

This time, in order to ensure that the people of Yongping Mansion have a harvest, he specially brought a new crop that had just been successfully planted, this thing likes cold and cool, it is a crop that likes low temperatures, and it is easier to plant in the north of Daming than sweet potatoes, this thing is of course a potato.

According to the research statistics of later scholars, the total amount of cultivated land owned by the Ming Dynasty is not less than 600 million mu, and the population will not exceed 150 million.

It can be seen that men, women and children have an average of more than four acres of arable land, and four acres of arable land can only maintain a fragile balance, and in the event of a natural disaster, a large number of people will starve to death.

Later generations had a population of nearly 1.4 billion, the red line of cultivated land was 1.8 billion mu, floods, droughts, typhoons and other natural disasters every year, and after the reform and opening up, I had never heard of anyone starving to death, but I often heard that food waste was serious, and half of the dishes in too many restaurants would turn into swill.

It is estimated that in the future, one acre of land can produce grain to meet the needs of a person, as well as the supply of poultry eggs and meat.

In fact, poultry eggs and meat are also converted from grain, roughly three catties of grain into one catty of eggs, less than seven catties of grain into one catty of pork.

At the end of the Ming Dynasty, the output of more than four acres of land could not meet the food and clothing line of the people, resulting in a large number of people starving to death.

Xu Guangqi came to Yongping with enthusiasm to guide the farmers to save themselves through production, but unfortunately suffered a cold reception.

Because he was a member of the imperial court, he came to the local disaster relief but did not bring food and real money, so that everyone scolded the war refugees who repaid their hopes.

Although Xu Guangqi was a wise man and a great scientist, he did not understand that people's hearts were less than eight or nine times out of ten, and he only brought more than 50 officials, family members, and several carts of potato seedlings and sweet potato seedlings that followed him to participate in breeding, which were equivalent to agricultural technicians in later generations.

The peasants of this era are even more uninformed, and basically no one cares about these agricultural scientists, and no one is willing to spend energy on growing these unknown things.

The officials of Yongping Mansion also did not want to see this Zuo Shilang of the Ministry of Rites, who basically came empty-handed to provide disaster relief, but on the surface, they were polite to this Zhengsanpin master, and they were all pushed to help with things.

The officials at all levels have a very good reason, Yongping Mansion is in ruins, and the people who are in trouble with their homes are waiting to be fed, we are busy every day, and we are doing our best to share the worries of the imperial court, and we really don't have time to help Lord Xu force the people to plant the novel crops you brought.

Xu Guangqi was in a hurry, the seedlings he brought needed to be planted in time, and the second seedling selection had to be carried out when the vines grew to meet the large-scale planting.

If the agricultural season waits for no one, and if the time is delayed for a few more days, the ripening period of sweet potatoes may catch up with frost, which will directly affect the yield.

Although he had no personal relationship with Zheng Guochang, the political envoy, he was also familiar with each other, so he came to the door hoping for help.

The scientist thought that it was really not possible to raise these disciples with great painstaking cultivation even at the expense of an administrative order, and the seedlings he brought all the way to the ground in a hurry.

This is the sad thing about the late Ming Dynasty, Xu Guangqi has successfully cultivated sweet potatoes that can be grown in the northern Ming Dynasty, although long-term consumption of this thing as a staple food in large quantities will lead to malnutrition and a decrease in intelligence value.

Later, the Chinese were called the sick man of East Asia by Westerners because of their thin yellow muscles, short and weak, which had a lot to do with the long-term staple food of these unnutritious coarse grains. But it is better to have sweet potatoes to satisfy hunger than to starve to death!

In later generations, the yield of normal cultivation of sweet potatoes per mu can reach five or six thousand catties, and the high-yield cultivation can reach more than ten thousand catties, this is because there are good varieties and chemical fertilizers available, of course, there will not be such a high yield in the Ming Dynasty, according to the records of the Manchu Qing Dynasty, harvesting eight hundred to one thousand two hundred catties can still be done.

Therefore, it was actually potatoes and sweet potatoes that supported the so-called prosperous Kangqian era and fed three or four billion people.

Zheng Guochang is really busy, Yongping Mansion has just been won, and there are so many problems that he, the supreme governor, has to solve.

The first problem is still the food problem, too many people have been looted and become destitute, and they can't survive without relief, and the food seized from Yongping City is only more than 40,000 stones, and the needs of maintaining the population of the city this year are relatively reluctant.

In fact, the Houjin army hoarded more than 100,000 stone of grain in Yongping Mansion, but it was taken away by the "Red Flag Army" that was the first to enter the city.

Not to be outdone, the white pole soldiers took about 30,000 stones, and the other battalions stretched out their hands again, so when Zheng Guochang took over, there were only more than 40,000 stones left.