The problem of new food is also difficult to solve, because the world's most productive food seems to come from the Americas. Whether it's sweet potatoes or corn, only hybrid rice is produced in modern China.

High-yield grain is temporarily unavailable, and Jia Siqian can only use relatively high-yield grain for farming. Zhang Yi also had to set his sights on the Americas, and at the beginning of his decade in China, he used his favorite explorer Xu Xiake, and asked him to take a boat from the four islands of Japan to the north, looking for the Asian-American land bridge, and searched for the Americas all the way.

But almost ten years have passed, and Xu Xiake still hasn't arrived in the Americas. This has something to do with Xu Xiake's frequent illness, he basically didn't take a boat in the first forty years, and suddenly went to the sea, of course, he couldn't adapt to it.

Zhang Yi has already made an order to ensure Xu Xiake's health. Xu Xiake has always been the most adventurous of his men. When attacking Yizhou, the distance from Wuxian to Yufu was very short, but it was blocked by Xiongguan.

In history, after Liu Bei was defeated in Yiling, he relied on Yufuguan to block Lu Xun's army. Everyone may be unfamiliar with this place, but if you say another name, White Emperor City, everyone will know it.

When Zhang Yi attacked Yufu, he took Xu Xiake to lean out of the path, and after bypassing it, he successfully reached the back of Yufu, and the city wall was short, so it was easy to overcome.

And the way that Lin Fengxiang and others attacked Yizhou from Jiaozhi was also explored by Xu Xiake. The roads there are between big rivers and rivers, and it is extremely difficult to get there, if it were not for Xu Xiake who spent two years exploring the road, it would be difficult for Lin Fengxiang to enter Yizhou in a short time.

Since then, Xu Xiake has been active in Southeast Asia, providing technical support for Fu Youde, Lin Fengxiang and others to occupy the Indochina Peninsula.

In the first month of the 19th year of China, Xu Xiake once again set out from Risi Island to the northeast, and after they completed the final supply at Haibei Island (present-day Sakhalin Island), they continued to explore northward.

In February, a land made of ice was discovered. With the previous experience, Xu Xiake immediately made the fleet go east.

During the first few voyages, I was almost stuck in an iceberg because I was walking close to the ice. If it weren't for the low speed of the ships, the entire fleet would probably be loaded on an iceberg.

This time, I avoided the places where the icebergs might exist early, sailed for a month, and finally encountered land. However, the land is full of trees, and there is no trace of human activity at all.

However, Xu Xiake was not disappointed, he led people to collect some wild fruits in the woods, hunted some animals, replenished food, and continued to the south.

After walking for another half a month, Xu Xiake was still sick. The captain wanted to return with Xu Xiake, but was dissuaded by Xu Xiake.

"Your Majesty's greatest trust in me is to let me find species that are not found in the Central Plains. Now that we've reached our destination, we're only one last step away from acquiring species, and we can't back down just because I'm sick. ”

At Xu Xiake's insistence, the fleet sailed for another half a month, and finally found traces of human activity on the coast.

Xu Xiake brought people into contact with the locals, and found that the language of this person was similar to that used in the Shang Dynasty.

There were scribes who knew the ancient language on the ship, and there were basically no obstacles to communicating with them.

The scribes learned from the natives that these people were actually immigrants from the Yin merchants. When the Shang Dynasty fell, the ancestors of these people were conquering Dongyi.

The ancestors of these people did not want to be ruled by the Zhou dynasty, so they migrated northward, all the way from the Yan land to the northeast, from the northeast to the Asian-American land bridge, and finally through the land bridge to the Americas, and then all the way south.

The Asian American Land Bridge is actually the ice layer around the Bering Strait, which was covered with snow and ice for a very long time in ancient times. This would allow beasts and humans to cross the Bering Strait from the snow and ice to travel between the two continents. The ancestors of these Yin Shang immigrants came to the Americas by chasing herds and migrated to the Americas.

After the language communication, these people also knew that the Central Plains region was developing very well, and they were also very happy. The two sides began to exchange cultures and exchange goods. Xu Xiake successfully exchanged the corn, sweet potatoes and potatoes he was looking for from these Yin merchant immigrants. According to the descriptions of these Yin Shang immigrants, it is very suitable for high-yielding crops.

Not only these three, Xu Xia also brought porcelain and gold and silver coins on board in exchange for peanuts, sunflowers, peppers, zucchini, kidney beans, pineapples, cashew nuts, papayas, tobacco, and two plants with the same name as lychee and pomegranate.

Xu Xiake recuperated here for four or five months, and when he recovered, he began to prepare to return home.

After three months, I finally returned to Shanghai Port in December. The seeds were transferred to a fighting ship in the port of Shanghai and transported to Shouchun.

Zhang Yi learned that Xu Xiake had returned with the seeds, and immediately went out of the city to greet him.

"Your Majesty, the minister is worthy of his mission!" Xu Xiake met Zhang Yi.

Zhang Yi hurriedly said, "Quick, let me see the seeds!" ”

Xu Xiake immediately opened the box containing the seeds and showed the seeds to Zhang Yi. Zhang Yi grabbed the corn seeds, looked at the sweet potatoes, potato rhizomes, and then looked at other seeds. Zhang Yi immediately ordered: "Jia Siqian cultivates in the royal farms in Shouchun and Panyu, observes the habits of these grains, and selects suitable species for promotion." ”

Jia Siqian was next to him, and hurriedly bowed down and said, "Obey the order!" ”

Zhang Yiyou announced the reward for Xu Xiake and others, "Xu Xiake and others went overseas to bring back seeds. Xu Xiake is now named king, and the rest of the fleet is made a prince according to merit, and it is reported to me after consultation between the prime minister and the province of Shangshu. ”

"Thank you, Your Majesty!" Xu Xiake and the others immediately thanked Zhang Yi. Xu Xiake knew that the credit would be great this time, but he didn't expect to be crowned king. The fleet personnel who followed Xu Xiake to Shouchun were also overjoyed, and according to Zhang Yi's will, they would also be named Pavilion Marquis at the very least. You must know that the conditions of China's feudal marquis are very harsh, if you want to cross the sergeants, generals, marquis and liehous in front, you need to kill at least 100 enemies, a fierce general can kill 10 people in a war is already the limit, to be a feudal marquis at least 10 wars to fight more than 10 wars.

How could Xu Xiake and others know the role of corn, sweet potatoes, and potatoes. As long as there is only one of these three high-yield crops, with China's original land, 200 million people can be fed. During the Qing Dynasty, 400 million people were fed by sweet potatoes alone, and there was no problem at all for 200 million people to be fed. Now China's arable land is more than twice that of the Qing Dynasty, and there is more fertile land, so there is no problem in feeding 500 million or 600 million people at the current level.