Wei Yan had already guessed what they were thinking from the changes in the expressions on the faces of the Huns, and the dilemma in front of these ordinary Huns soldiers now was how to surrender peacefully, because there were more than 20,000 Hun soldiers who were loyal to the nobles of the head, and if these ordinary Hun soldiers wanted to surrender, they would inevitably be killed by these die-hard Hun soldiers behind them.

Wei Yan ordered someone to shout in the Xiongnu language: "Those who are willing to submit, jump off the trench, discard their weapons, and run to both sides of the trench!" ”

These trenches were dug overnight by the sappers of the Wei army led by thousands of auxiliaries, and they were able to dig trenches more than two zhang wide and five feet deep and more than half a mile long under the noses of the Huns.

Of course, the Wei army had already sent elite scouts to clear the secret outposts planted by the Huns on the outside of the valley before they set out, otherwise Zhang Yan's Feiyan army would not have touched Qingyan Mountain so smoothly to dump oil.

The trench more than three feet deep constituted a great obstacle to military operations, but it was nothing to the victorious Huns, who all jumped into the trench and ran quickly along the trench to both ends, where Wei soldiers had already been there to meet them.

In order to prevent some Xiongnu leaders and nobles from secretly sending people to destroy, before letting these Xiongnu troops come up, they were ordered to drop their weapons, and those who dared to carry weapons and touch them were all shot.

The ordinary Huns ran forward along the plank road, and when they reached the edge of the trench, they jumped down without thinking, fell on the edge of the trench, turned over and got up, and did not even have time to pat off the dust on their bodies, and ran to both ends of the trench with a puff of smoke.

This has formed a mighty and unstoppable tide, there are the Hun leaders and nobles who dare to prevent these Huns from escaping back to meet their wives, children, cattle and sheep, all of them are hacked to death by these Hun soldiers, after all, there are more than 80,000 ordinary Hun soldiers, and there are only more than 20,000 of those die-hard Hun soldiers, four against one, and the results speak for themselves.

Wei Yan knew very well that it was still a bit difficult for these ordinary Hun soldiers to raise their knives and slash at their original head nobles, after all, these head people and their families had been very powerful in the past few hundred years, and these Hun soldiers were still a little afraid in the face of them, but when they let them escape and go back to see their wives and children, cattle and sheep, it was their enemies who dared to obstruct them, then there was nothing to say, kill!

More than a dozen tribal leaders have been beheaded by soldiers fleeing from their own tribes.

Seeing that the general trend was gone and irreversible, the remaining tribal leaders ordered the loyal and brave tribes below to disperse to the burned grassland below the plank road, and let the ordinary Hun soldiers escape.

These tribal leaders have made up their minds, this fire can not be endless, and when the fire is extinguished, they will flee over the mountain, go to the Xianbei people, and then borrow the Xianbei people's soldiers and horses to restore their power.

The fire burned for three days and three nights before it was slowly extinguished, and those tribal leaders crossed Qingyan Mountain, ready to go north to the western Xianbei adults, but found that there were already tens of thousands of elite cavalry waiting for them under Qingyan Mountain, they thought that the adults in the western Xianbei heard the news and came to the rescue, so they rushed over ecstatically.

When they got closer, those 50,000 elite cavalry opened their fangs, and it turned out to be 50,000 cavalry led by Xu Huang, the general of Duliao.

In addition to the 10,000 guards cavalry equipped with bilateral stirrups, Gaoqiao saddles, and horseshoes, as well as Liu Bao's 40,000 Southern Hun cavalry, these 40,000 Hun cavalry have long been firmly controlled by Wei Yan with the army system, Liu Bao is only a nominal commander, Xu Huang, Tai Shici, Zhu Ling under the command of the three generals, 50,000 cavalry who have been recuperating for more than three days, like a group of hungry wolves pounced on a group of lambs.

Most of the war horses of these tribal leaders were burned to death in the Qingyan Valley, and the remaining war horses also fled to the arms of the Wei army along the plank road, these tribal leaders led their 20,000 die-hard soldiers to go over the mountain, and failed to carry a horse, and they were used to riding horses and stood on the flat ground with Luo circle legs, and how to resist the 50,000 elite cavalry of the Wei army, the one-sided slaughter lasted not long, and the original die-hard Hun soldiers turned back and killed those head nobles.

The most regrettable thing in this battle was that more than 90,000 war horses were burned to death in the valley.

Wei Yan originally didn't want to fight like this, but he had already received a rumor, and the western Xianbei didn't know how to learn that he was going to lead his troops to plot against them, and they had already entangled 150,000 cavalry and prepared to go south to attack him with the Xiongnu coalition army in the hinterland of Hetao.

If Wei Yan attacked the 140,000 Hun cavalry, even if he won, it would be a tragic victory, and it would be difficult for the exhausted Wei army after defeating the 140,000 Hun cavalry to win the 150,000 iron cavalry of Xianbei, Wei Yan really had no choice but to set fire to the mountain.

Taking a step back, it is better to burn these more than 90,000 war horses in the valley than to cheapen the Xianbei people who followed, because there are not so many cavalry in Wei Yanwei's army who can control so many war horses.

For the Wei army, war horses are easy to obtain, riders are hard to find, a farmer cannot become a qualified cavalry in a few months, even after the cruel training of the Wei Yan Wei army, it is difficult to keep up with the Xiongnu and Xianbei people who have grown up on horseback since childhood.

After the end of this battle, the Xiongnu tribes in the Hetao area were cleared.

From then on, there were no tribes, only four types of Huns.

Wei Yan selected 20,000 cavalry from all the Xiongnu men, divided them into battle auxiliaries, formed a division of their own, and handed them over to Xu Huang, who was good at commanding cavalry.

More than 800,000 Huns lived in the entire Hetao area, and more than 30,000 were burned to death in the valley, and the rest succumbed to Wei Yan's force.

Wei Yan understands that this Hun is different from the Qiang people, the Qiang people are more and more pressed, and they have not given in after fighting with the Han people for a hundred years, and the current Huns are a bit like the later Goryeo sticks and Japanese people, afraid of power but not virtue, being good to him is not enough to make him grateful to you, you must subdue them, first beat them with a big stick, and then give carrots to tame them.

Qingyan Mountain set fire to the remnants of the Southern Xiongnu people, and from then on, they no longer dared to slash in front of the Han people, but obediently accepted the complete sinicization in accordance with Wei Yan's policy.

Together with the more than 700,000 Huns in Senei, who were nominally ruled by Liu Bao, a total of 1.5 million Huns lived in the territory of the Han Dynasty, except for the more than 100,000 Huns who fled north and joined Xianbei, and more than 1.4 million Huns were all Sinicized.

One after another, 100,000 Xiongnu elite men were incorporated into the Xiongnu Corps, forming five divisions for the Wei Army's external corps and serving Wei Yan.

One after another, more than 800,000 Xiongnu people stopped grazing and turned to farming, and began to develop the Hetao area together with immigrants from other states and counties.

Many ditches began to be built, many waterwheels were built, and countless wastelands were turned into fertile fields, and plugging the south of the Yangtze River was just around the corner.

For these Xiongnu people who are willing to accept the cultivation civilization of the Han people, as long as they can be completely sinicized, can actively speak Chinese, write Chinese characters, wear Han clothes, change their Han surnames from Han customs, and start plowing the fields, they can use the seeds, farm tools, and ploughing cattle of the Wei army for free, as long as they are returned as they are at that time.

Wei Yan's regulations are to promote the process of sinicization of the Xiongnu, and there is no ethnic equality and actual ethnic discrimination, because for Wei Yan, there can only be one nation in the world, that is, our Han nation, and the Xiongnu nation will not continue to exist.

More than 300,000 Huns continued their grazing life, but they were all registered as household registrations, and according to the armor protection system that had been in place for nearly a year in Sizhou and Bingzhou, and the pastures were limited and they were strictly forbidden to move to a large extent.

In order to prevent the ecological environment of the Hetao area from deteriorating to the situation of future generations, Wei Yan specially issued a strict animal husbandry policy, strictly limiting the number of sheep and horses owned by each tribe, because these two kinds of livestock are very destructive to the pasture, sheep can gnaw all the grass no matter what, and the horses are too mouthful of good grass and do not eat, they also like to gnaw and plane, and the fertility of defecation is relatively low.

Wei Yan plans to continue to extend this policy of restricting horses and sheep to the entire Saibei grassland, just to limit the invasion of nomadic people such as Xianbei and Ding Ling into the Central Plains, because they raise too many horses and sheep, and the original pastures are overwhelmed, and then the livestock are not full, and those tribes will find it difficult to survive, so they will fight for more and better pastures, and the small and weak ones will be wiped out, and the remaining big and strong ones should go south to fight the Central Plains. As long as the number of sheep and horses owned by their tribes was strictly limited, they could reduce their chances of going south to invade the territory of the Han Dynasty.

Cheng Tianchou, the servant who came to Qingyan Mountain from the Xianbei Royal Court, was the highest official in charge of the entire animal husbandry industry, and when he heard that Wei Yan had such a motion, after reporting the details of the envoy, he asked directly: "My lord, if these grassland herdsmen are not allowed to graze horses and sheep, then what will they do for a living?" Where do our horses come from? ”

Wei Yan shook his head lightly and said with a smile: "Zitai, it is to restrict overgrazing horses and sheep, not not to graze horses and sheep, but to change from paying attention to quantity and ignoring the environment to attaching importance to breeding quality and protecting the environment." ”

Wei Yan deduced the consequences of overgrazing in detail for Tian Chou: "Originally, this Hetao grassland, like the Mobei grassland, is a thin layer of soil under the grass and trees, and under this layer of soil is a thick layer of sand and gravel, this grassland can only grow so much grass, can only support so many livestock, if you raise too many livestock, especially too many goats, the consequences are unimaginable, the hooves of goats are like pickaxes, beaks like tongs, and horns are like shovels, and they can pour the top of the tree to eat leaves, and they don't even let go of the roots when they eat grassAfter a heavy rain, the thin soil will be washed away by the heavy rain, revealing the sand under the soil layer, and in the long run, the grassland will degenerate into a desert. ”

Tian Chou originally didn't think so, but when he heard Wei Yan say this, his expression became solemn.

Wei Yan picked up the map of the Hetao area and pointed to a place: "This place is called Baichengzi, two hundred years ago, the water and grass here are abundant, the grass beach is vast, the river is clear, it used to be the location of the Hun royal court, and then the Huns overgrazing, the grass here was all eaten by horses and sheep, and the Huns did not know how to plant grass to consolidate the water and soil, so that the sand was raised on the spot, forming the current sandy land." ”

Wei Yan said that Baichengzi, is the later generations called the Mu Us Desert, in the Western Han Dynasty, this area of water and grass is fertile, the scenery is pleasant, is a good pasture, the most primitive desert is only in the west of the sandy land is a small area, but because the shallow surface of this grassland is composed of gravel materials formed in geological periods, once the turf is destroyed, it becomes a desert, so, after excessive nomadism, the desert finally spreads to the surroundings like a piece of infectious psoriasis, so that in the Ming Dynasty, it is completely desert.

Wei Yan led Tian Chou and other officials in charge of agriculture and animal husbandry to the trench they had dug earlier, and asked them to see the distribution of soil layers.

Sure enough, there is a very thin layer of soil under a layer of grass, and there is gravel under the soil layer, once the grass on it is gnawed by horses and sheep, and the next heavy rain and a strong wind blows, this thin layer of soil will all be taken away by the wind and rain, and it will become sandy land here, and then it will deteriorate, and the pieces of sand will become a desert.

Tian Chou, Han Hao and other officials in charge of agriculture and animal husbandry couldn't help but change their faces greatly, and from the vivid analysis that Wei Yan showed them, they realized that if they didn't pay attention to environmental protection, the current grassland might become a desert in the future, and no one could afford such a responsibility.

Wei Yan also talked about a very sensational consequence: "There are many rats living on this grassland, there are voles and gerbils, these rats generally live in very low grass and trees, close to bare places, as long as the grass and trees grow tall and the rhizomes are tight, those rats will not be rampant, but once the grass is gnawed away and the soil layer is soft, those rats will begin to flood, not only gnawing on the grass that has just returned to green, forming a competition with livestock, but also digging burrows everywhere, after the rats have more burrows, The soil layer and the grass root system have been seriously damaged, followed by the degradation and desertification of large grasslands, and the extremely sandy grassland is very suitable for long-clawed gerbils, a gerbil can dig out thousands of catties of sand, and these sandy soil are turned out of the ground by gerbils, thousands of gerbils flood a grassland, can turn a grassland into a desert in a very short time. ”

If these officials were in Yiyang New Town, surrounded by mountains and rivers, and had not seen this prairie under the blue sky and white clouds with their own eyes, they would not be able to empathize, and they would not have resonated with Wei Yan's words, but they went out with the army and came to this grassland, and the prairie where the wind blows the grass and sees the cattle and sheep makes them intoxicated, and after being intoxicated, they can't help but be frightened into a cold sweat when they hear Wei Yan's words.

Tian Chou, Han Hao and the others bowed down and said, "Please make it public, what should be done to prevent this prairie from becoming a desert." ”