After repairing in Xicheng for a few days and fully grasping the local situation, Li Su continued westward to Shangyong under the guidance of the Shen family.

To tell the truth, this area is the first time he has been a human being in two lifetimes. I personally experienced it by boat, and I knew the danger of the road - from Xicheng downstream, it only takes one day to reach Wudang through Dangxian, a full 600 miles away.

Of course, this is not a straight-line distance, and the straight line is only four hundred miles, because the Han River is meandering.

The speed of the ship is so fast, it can be seen that the drop of the Han River in the Qinling Mountains is large, second only to the Three Gorges section of the Yangtze River, and far more turbulent than the Jialing River and the ditch that Liu Beijun experienced during his previous campaign.

This means that the boat is driven by oars or sails, and it is impossible to swim against the current - no wonder in history, after the death of Zhuge Liang, when Jiang Wan was in power, Jiang Wan proposed to change the Northern Expedition strategy and concentrate troops to recover the three eastern counties, but it was opposed by the government and the opposition, and the reasons for the opposition were also very uniform:

From Hanzhong's condescending downstream impact, it is easy to take Xicheng and Shangyong. But if it is taken, it is just a piece of "surplus land", and it cannot feed back the people's financial and military strength in Hanzhong.

Because even if you grow surplus grain and produce surplus military supplies in Shangyong, you won't be able to transport it back by the Hanshui waterway. Unless you have the courage to go down the river directly to capture Xiangyang, it is a waste of national strength to just take the mediocrity. During the Jiang Wan period, the national strength of Shu Han was obviously unable to defeat Xiangyang and it was impossible to hold Xiangyang, so he had to give up.

"I didn't expect the river in this place to be so steep and turbulent, and if I didn't come once, I really didn't know that the transportation infrastructure was worse than that of Ba County." Li Su looked at the Qinling Mountains on both sides of the strait, and couldn't help but sigh in his heart, and even couldn't help but sing and laugh and scold:

"Between the colorful clouds in the west city, six hundred Wudang returned in one day, the apes on both sides of the strait couldn't stop crying, and the light boat had passed over the ten thousand mountains."

"Oh, Li Zhonglang is a good poet. The world only knows that there are five words in Yuefu, and Zhonglang actually created seven words, which are catchy. Shen Kai, who led the way, listened to his whispered chant and hurriedly patted his ass. But Dian Wei didn't understand anything next to him, and he didn't know how to applaud.

Li Su was in a bad mood and rudely interrupted: "What a fart—don't write it down!" I am cursing the sinister Qinling Mountains, lamenting that it is not easy for the people to enter and exit, and the imperial court cannot mobilize the people's and material resources. What to remember this kind of vulgar language that criticizes heaven and earth!

By the way, let's get down to business, let me ask you - you have lived in the upper mediocre for a long time, do you know that the people here have any other way to sail against the current? You can't just go down the river every time you don't drive back, right? ”

Shen Kai was scolded, but he didn't dare to be angry at all, but sighed from the bottom of his heart: Li Zhonglang is worthy of being a great sage in the world, not only knows the destiny of heaven, but also speaks into chapters, cursing God and scolding God so casually!

Sycophants are sycophants, the question still has to be answered, Shen Kai accompanied the careful explanation: "The people here rarely sail, occasionally, only to transport goods downstream, and when they return, they encounter a torrent that cannot be rushed, so they can only pull back on the shore and cross the beach, which is extremely hard, so the business travel is almost extinct." ”

Li Su listened carefully for a while before he understood the meaning.

He also saw on the way here, not all sections of the river are so turbulent, but there are so many or four in total, and the bureau tribe is too big and too urgent. Except for these three or four sections, the rest of the river can be reversed by rocking oars and sails.

Once you reach the rapids and rapids, you have to unload the cargo from the ship, move it to the shore and walk through this section, and then pull the lighter empty boat upstream to cross this section before loading it.

After Li Su learned about it, he only knew that the people would work so hard to transport salt, because there was no salt in the Qinling Mountains, and salt had to be eaten.

The mediocre price of salt is actually hundreds of dollars per bucket more expensive than the outside world, and the difference in price is the hard-earned money of the salt carriers.

Li Su couldn't help but think: "The entire Shangyong area should have a population of nearly 100,000, Xicheng is more than 5,000 households, more than 20,000 people, Shangyong County has more than 8,000 households, more than 35,000 people, and the other 7788 add up, counting Fangling, a total of 40,000 people."

Since there is a demand, and there are still so many sloping lands on both sides of the Hanshui River Valley that can be reclaimed, and the irrigation conditions are good, it can be used to resettle displaced people in the future.

Nowadays, there are not many places affected by the war, Shu is very rich, and the population of the three counties of the Chengdu Plain has long been saturated and entered the Malthusian trap. In the future, the continuous war and chaos in Yongliang caused by Dong Zhuo, Han Sui, Li Dao and Guo Yan and the southward flow of population will definitely not need to be put into the Chengdu Plain, so they will be settled in Hanzhong on the spot.

Then, there are areas with sufficient irrigation and easy reclamation, which are also Brazil and Shangyong, where as long as you find a way to repair a few diversion locks that do not need to intercept the river, and solve the problem of the return of downstream ships, it is simply a great benefit. ”

The locks were not always the same as those found on the side of the dams of the hydropower stations in later generations, and the entire river had to be cut off. Instead, you can dig a little mountain to lead a branch canal out, and then make two gates at the end of the branch canal, and use a large waterwheel to twist the switch.

Especially when encountering a place with a large drop and often an S bend, you can cut the bend and straighten it, directly on the mountain upstream to block the flow of water, choose a shop where the mountain itself is relatively low, and dig a small gap.

The amount of excavation work is definitely a bit large, but because it is only a few tens of meters long, it is still acceptable, the amount of work of a lock, it is estimated that it is equivalent to digging dozens of miles of canals on the soft plain, and the technical level is the lock of the Ming and Qing dynasties, and the difference is more than three or four stories high.

Otherwise, the gate of this era can only be tied by big trees, and no matter how deep it is, it is impossible to find such a long and thick tree, and at the same time, it is afraid that the gate formed by the big tree is not strong enough to support the deepest water pressure.

When there is gunpowder that can blast the gap in the mountain, and enough Yongliang displaced people, you can consider starting construction.

However, once he really made up his mind to do so, Li Su also had to consider the strategic security of Hanzhong in an all-round way -- there was no lock in the beginning, and Xiangyang could not counterattack Hanzhong, and it would not be able to swim up at all.

Li Su noticed that the later generations were roughly Shiyan Wudang Mountain generation, and now it is actually deserted, and there is no county seat - Shangyong is to build water on the tributary, and it is necessary to trace the water along the Danjiang estuary in later generations for about 100 miles, but no one has developed the estuary area.

Li Su felt that if Shangyong was to be developed, it was necessary to build a county town near Shiyan to cut off the Han River and prevent people downstream from sneaking over. And all the locks built by Liu Beijun in the future must be located upstream here, and no one is allowed downstream from now on.

Li Su couldn't help but ask Shen Kai: "I see that the estuary west of Wudang Mountain, where the blocked water meets the Han River, is obviously more flat and fertile than Shangyong, why are there no people to settle down?" ”

Shen Kai is a local in the end, and he is very familiar with geography, so he answered sincerely: "Although this place is flat and the irrigation is convenient, the soil is not strong, all because of the Han River and the blocked water flow here gently, the sediment is silted, and the swamps are everywhere for dozens of miles. ”

Li Su nodded, only then did he understand.

This place is roughly the starting point of the middle line of the South-to-North Water Diversion Project in later generations, the Danjiangkou Reservoir, plus the Shiyan urban area in later generations. Since there are reservoir areas and alluvial plains, it must have been swamps in ancient times.

In later generations, Shiyan was able to build a city, but after thousands of years of sediment deposits, the swamp became a solid plain.

Now if you want to invigorate the entire Shangyong area, think about whether there is a way to use this swamp land into an agricultural area, and revitalize the entire Shangyong here.

Li Su didn't know much about this matter, so he had to ask for advice in the future.

……

"No matter, I see that the scenery of this Wudang Mountain is good, we will camp on the edge of the swamp west of this mountain, camp and wait for a few days, and wait for Zhao Yun to come over with reinforcements to meet, and then we will go to Zhuyang." After all, we are Hanzhong soldiers, and it is not good to bring too many people into Nanyang County.

In the future, I think that thousands of soldiers can be stationed here, and if rice and wheat cannot be grown in the swamps, then it is better to plant taro. After having grain stockpiled, the people of the garrison here can be self-sufficient, but the taro is not durable to store, and it is still necessary to transport some rice and wheat to tide over the spring famine. ”

After Li Su inspected it, he ordered the army to be stationed here, and by the way, he stuck the neck of Shangyong County, and asked Dian Wei to take some people to clean up the diehards on Shangyong's side who were not satisfied with Liu Bei.

Shen Kai on the side looked at Li Su's posture, and he was also slightly worried: This Li Zhonglang is very ambitious, is this going to farm here? If it is easy for outsiders to come in in the future, the emperor of the Shen family will not be able to be......

However, it shouldn't be so easy, wait and see for a few years first, and you won't offend Li Zhonglang.

About a week later, Dian Wei completely wiped out Shangyong County and returned with soldiers.

Around the same time, Zhao Yun also arrived at Wudang Mountain with some reinforcements and joined Li Su.

And under this week's investigation, Li Su also found some common problems in farming in the late Han Dynasty, so he cooled off on Wudang Mountain, while writing something in a small notebook, ready to go back and tell Liu Bei to organize the people to learn new skills.

When he was in Hanzhong before, Li Su found that many people in this era did not know much farming skills, or that the crops they could grow were very pitiful, and they would not be able to plant anything else, and no one would teach the people.

The most advanced agricultural book in this era is "The Four Peoples Moon Order", Li Su had not read it in his previous life, but after arriving in Hanzhong, he specially asked people to find a copy of "The Four Peoples Moon Order" to look at, and found that the gap with the "Qi Min Technique" in the Northern and Southern Dynasties is still very large.

The key is the tone of the author of "The Lunar Order of the Four Peoples", at first glance, he is a big housekeeper of a powerful manor, who knows how to organize and dispatch serfs throughout the year, how to make full use of the land, and take turns to plant all kinds of vegetables and fruits. And very few of the people understand this.

Li Su was in Shu and saw that Sichuan pepper was already a mature commercial commodity, which was very expensive, as was tea, and the kind of fruit used to make wolfberry sauce. But the people will not "cultivate" this crop, the supply is from the medicine farmers who go up to the mountains to collect medicine, and all the harvest is pure wild.

In the same way, the place that Li Su wants to govern now is said to be able to rely on water to draught, and it doesn't matter if there is a swamp, but the people can only fish, and they have never thought of raising fish, and the taro is also dug wild in the swamp, and few people regard it as a crop, but "harvested from wood".

If we really enlighten the people's wisdom, let the surplus population in the mountainous areas of Shudi know that "the hillside land can also take the initiative to plant pepper, tea trees and sugarcane", and let the surplus population in the swamp area learn to raise fish and taro, why would Yizhou's population of one to six or seven million be rolled up in the Malthusian trap.

There is still a long way to go.

In the process of recovering the mediocre land, the military and political challenges can be said to be almost negligible, but the sense of powerlessness in other aspects makes Li Su very depressed.

Although he doesn't understand Qi Min's technique, he can still do it according to the "Four People's Moon Order" and let some old farmers summarize the methods of planting these cash crops that "people don't think are crops at present", and Li Su's record is converted into words.

And there is no need to write it yourself, the text can be handed over to Zhuge Jin and them.

Li Su finally left the Shangyong Mountains in mid-June, and on June 18, he left most of his men and horses on the side of the Yizhou boundary to stand by, and he arrived in Xiangyang with his fleet, and then inquired about the situation in the court.

Knowing that Dong Zhuo was still delaying time in Hedong, He Jin had not made any moves, and the imperial court's restrictions and accusations on the cross-border movement of foreign troops were indeed much more lax than when Emperor Ling was in power.

Only then did Li Su amplify his courage and asked Zhao Yundianwei to bring 500 cavalry, as the name of the escort of the Hajj mission, from Xiangyang to Huashui and arrive in Nanyang.

Then he got on the boat and landed on the shore, took the land route from Nanyang, and went straight to Yique Pass on the border between Jingzhou and Sili.

However, before entering the Si Li, Li Su asked Zhao Yun to hide the banner, and then first sent a fast horse to secretly enter Beijing to inquire about the progress of He Jin's struggle with the eunuchs, while Dian Wei walked slowly under the false banner.