Li Yu's attitude towards Sha Tuo still made many ministers who knew about it slanderous, and if they were other emperors, even if they would not jump up happily, they would welcome each other, at least they would send troops to greet them, such as Emperor Taizong, who welcomed others to surrender to him. However, Li Yu scoffed at this kind of argument, accepting the surrender of others also depends on the strength, Taizong Gaozong Xuanzong when the Tang Dynasty was strong and powerful, and the people who surrendered were often sincere, even if they had any ideas, they couldn't make any big waves. But what was the result of Emperor Wu of Liang's acceptance of Hou Jing's surrender? Starve to death. Three generations of grandparents and grandchildren have taken in. When Fu Jian unified the north, people from all over the world also came to surrender one after another, and they were respectful to Fu Jian, and when Fu Jian was defeated in the battle of Weishui, the remnants of various countries immediately rebelled, and the former Qin quickly went from strength to destruction. The current Tang Dynasty did not have the strength to accept the surrender of the entire tribe.

Therefore, Li Yu is now sending spies to inquire about Shatuo's situation, and on the other hand, he is busy with matters related to agriculture and maritime trade. Pei Yan's five strategies for persuading agriculture gave Li Yu great inspiration, and the idea of building agriculture was formed after that. After all, the Tang Dynasty was an agriculture-oriented country, and it also needed food to fight wars. What does it mean that the land area of the Tang Dynasty was larger than that of the Song Dynasty, but the grain output was not as good as that of the Song Dynasty? It shows that there is a big gap between the land development and production technology and even the crop quality of the Tang Dynasty and the Song Dynasty, and there is a huge potential to be tapped. So at the beginning of the third year of Yongzhen, the agriculture of the Tang Dynasty came into being.

According to Li Chen's idea, the headquarters of agriculture will be set up in Chang'an, and then set up branch schools in Hezhong, Luoyang, western Zhejiang, Lingnan and other places, but because Liu Zongyuan is trying to plant Zhancheng rice in Lingnan, the branch of Lingnan has been established before the headquarters, and Liu Zongyuan, who has a lot of money, is from Tuntian, and after obtaining Li Chen's permission, this year in Lingnan, which is vast and sparsely populated, suddenly expanded the trial planting area to 10,000 mu, and went to more than 2,000 immigrants. The latest piece of music says that the yield of Champa rice is more than that of local rice, and if it is replaced by skilled farmers who cultivate it intensively, it is not impossible to double or triple it, and most importantly, Champa rice is drought-tolerant and waterlogg-resistant, and it only takes more than 50 days from sowing to maturity. Liu Zongyuan believed that he would be able to provide 30,000 rice seeds by this year, and this report made the entire court full of expectations for the future of agriculture.

The success of Lingnan Agronomy's trial planting of Champong rice has become a foregone conclusion, and the imperial court has also given a rich reward, because of the merit of sea trade and the introduction of trial planting of Champong rice, Liu Zongyuan has now increased the rank of doctor, and Liu Zongyuan is now afraid that it is much more effective than the Lingnan Jiedu envoy. This can't help but make Chang'an Agronomic feel itchy and unbearable, and he is gearing up to get a new variety of wheat. However, Li Chen's first task to agronomy is cotton, you know, silk fabrics, the export of cotton fabrics in ancient China is a big profit, and Li Yu crossed the Tang Dynasty cloth opinions are really not small, it looks bright, it is not comfortable to wear, Li Chen's cultivation of cotton has begun two years ago, cotton in the Tang Dynasty is mainly used as an ornamental plant, planted in the royal garden, the use value has not been found, Li Yu originally had no hope for the royal garden that had gone through the war, When he found that there were still many times when he found cotton, he could be described as ecstatic, and immediately ordered the gardener to plant more, collect cotton seeds, and prepare to make a big one. Of course, the cotton after collecting the seeds has already been enjoyed by His Majesty the Emperor. Even if you can't weave, you can always put on a quilt, right? In short, the emperor had slightly more nosebleeds in the first year. Naturally, some courtiers expressed doubts about whether cotton could be weaved, but when Li Yu gave the example of kapok, everyone felt that it made sense.

There is a kind of kapok tree in Lingnan, the height can reach 30 meters, it is a deciduous large tree, this tree blooms in spring, bright red like fire, and is respected as a "hero flower". Its economic value is very high, there is cotton wool in the five-lobed fruit petal, it can be pumped into very fine silk cotton, the middle is continuous, and the cloth is woven into cloth with kapok silk and then dyed with color, which is very exquisite. This kind of cloth is called "tube muslin", and it is of high quality and high price. In the Southern Dynasties, there were officials who dedicated the Lingnan muslin to Liu Yu, Emperor Wu of the Song Dynasty, but unexpectedly patted the horse's hooves, and Liu Yu, who was born as a military general, thought that the muslin was "exquisite and laborious", which required too much manpower and was extravagant, so he ordered to prohibit the reproduction of muslin in Lingnan. Since kapok can be woven into cloth, why can't cotton be tried? There was no shortage of Cantonese Yankees among the ministers, so Li Yu handed over the task to one of them, and he was so happy that this guy ran to the experimental area assigned to him. Of course, if the people in the experimental area do not grow grain and cotton, the imperial court will also have to pay a price, that is, to send grain to the people.

The superintendent of agriculture is Li Yijian, a talent drawn out by Pei Yanjian. Pei Yan has always been known for knowing people well, and the talents he selects are often gentle and elegant, and have the spirit of hard work, which makes Li Yu especially fond of it, and never refuses the talents recommended by Pei Yan, which also makes Pei Yan have the same prestige as Han Chaozong at the beginning. The people who planned to go to his house to give gifts and make scrolls could simply arrange to Tongguan from a long time, which also made Pei Yan unbearable.

In mid-June, the imperial court formally defined the functions and powers of the municipal envoys. This was formulated by Li Yu with reference to the practice of the Southern Song Dynasty, combined with Liu Zongyuan's suggestion and the practice of later generations. According to the edict, the main responsibilities of the Municipal Envoy Department were:

1. To manage the entry and exit of ships, foreign and Tang Dynasty import and export ships, all must apply for permits, and the Municipal Shipping Department needs to check whether the ships are carrying contraband. For example, domestic tea, mulberry, silkworm and so on are strictly forbidden to be exported.

2. Tariffs on foreign goods shall be levied, with three out of ten extracts for coarse color (general goods) and one out of ten for fine color (precious goods).

3. Buying Tibetan goods, buying some imported Tibetan goods, such as pearls and spices, at official prices, or shipping them to Beijing, or reselling them.

Fourth, the management of foreign goods. Set up a special market to encourage trading.

Fifth, send personnel to go abroad for investigation, such as customs, geographical specialties, etc. are within the scope of the investigation.

6. Set up a shipyard to develop better and larger sea vessels.

The southeast coast, especially Lingnan, has been closely linked with overseas trade, and after two or three years of hard work, in addition to Japan, Silla and Southeast Asian countries, the trading countries have gone as far as Tianzhu, Dashi and even the east coast of Africa. According to Li Yu's instructions, Liu Zongyuan also specially recruited organizations to sponsor several seafaring groups, allowing them to open up new shipping lanes and collect new species. The main goods exported are porcelain, lacquerware, tea, silk, while the main imports are spices, pearls, coral, ivory, rhino horn, etc. Naturally, some people questioned why so many luxury goods were imported, and Li Yu said with disdain in his heart:

"Without so many luxuries, how can I get the money of the princes and nobles?"