Fortunately, Liu Bei is not the kind of person who only cares about enjoyment and has no ambitions, and after experiencing it for a while, he crawled out of the warm quilt and asked a core question.

"Lord Nakaro, I wonder if this biogas can be supplied all the time?"

The reason why he was willing to leave the Han land, where living conditions were better, and run to the harsh grassland to take risks, was simply because he knew that there was an opportunity to make contributions here, and he could realize his dream of becoming a big official when he was young. And from everything he saw after entering the city, whether it was in terms of high-end force or subsequent settlement and development, it could reflect that it was not a momentary idea for the other party to send troops to capture the nest of the Wuhuan people, but with a comprehensive plan, and even a little bit of the plan to dominate the grassland. Therefore, at this moment, Liu Bei couldn't help but become concerned.

Although he knew from the reincarnation who defected to him that as soon as Emperor Ling died, the world would be in chaos, but at present, Liu Bei did not have particularly big ambitions, but he didn't want to be mediocre and inactive for a lifetime.

Seeing Liu Bei's expression become cautious, Nanshan knew that the first step of subduing the other party had been preliminarily achieved, so he no longer hid anything, but said directly.

"Because before the winter, all the tribes will gather together, and this time the Wuhuan people left more than three million heads of livestock around the Wuliao Mountain, but after buying a large number of slaves and after some of the war consumption, there are less than 1.2 million left. Among them, there are 120,000 cattle, 750,000 sheep, and 320,000 horses, and the manure produced by each cow in a year will be about 10,000 to 14,000 catties (five to seven tons), sheep, about 2 to 4,000 catties (one to two tons), and horses, about 6 to 9,000 catties......

"There are so many." Liu Bei smacked his tongue and said.

Not to mention how many people can sustain the winter needs of the biogas provided by the manure, the number of livestock obtained from the Wuhuan people alone is an unimaginably staggering wealth and strength.

Because of the corruption of horse politics, the current animal husbandry situation in the Eastern Han Dynasty is not optimistic, and it has been reduced to the point of relying on foreign people to help raise horses (one of the conditions for agreeing to Xianbei, Wuhuan, and Southern Xiongnu is to help the Han Dynasty raise horses). Any war horse is worth 100 gold, and even Gongsun Zhan, who is close to the border, has only supported less than a thousand cavalry. That's 300,000 heads, and even if the number of adult horses is only one-tenth, it's an incredible number. It is no wonder that this Zhonglang general would venture into the grassland, with so many war horses, he has become the top force in the Eastern Han Dynasty at this time.

"Doesn't that mean that we can also have our own cavalry units in the future." Zhang Fei and Guan Yu glanced at each other, their expressions full of joy.

Don't blame them for being so excited, in this kind of world where individual force has an overwhelming advantage, except for some special troops, the gap between infantry and cavalry has been further widened, especially in the face of those generals who have reached the inhuman realm, after fleeing with two more legs, the survival rate is at least ten times higher. To deal with the former, the generals can pick up a few hundred, but against the latter, they may not have much strength after chasing and killing dozens of them.

The two of them are now military horses, and they can each command a thousand people, but among the 5,000 soldiers and horses brought over to support this time, the real number of cavalry is only about 400, and half of them still exist as scouts, and the number of cavalry that can be assigned to them can be imagined, which is completely better than nothing. Now, with so many wealthy horses, they can finally get what they want and form their own elite troops.

What the trio didn't know, of course, was that this was just the beginning.

At present, the number of livestock on the grassland is not in the eyes of Nanshan, you know, only in Inner Mongolia in later generations, hundreds of millions of cattle and sheep can be grazed, which does not include Outer Mongolia, Siberia, Central Asia and other regions, but also belongs to the current grassland range.

The key to this lies in the use of organic fertilizers and the complementary effect of high-yielding crops on animal husbandry.

The forage grass grown on those grasslands has little yield and low utilization, most of it is crude fiber, and the nutrients contained are insufficient, and adult animals have to eat at least a dozen kilograms a day to meet their daily needs. So, even if all the grasslands are planted with pasture, don't want the number of livestock to be very high. Not to mention the inherently limited use of manpower when grazing, and it is easy to encounter various unexpected situations, which cannot not only stabilize the reproduction of livestock, but also accelerate their growth rate like large-scale farming.

In order to achieve a certain number of scales, it is necessary to use the straw stems and leaves left over from high-yielding crops such as corn and sweet potatoes as feed for livestock, as is the case in modern animal husbandry.

Therefore, Nanshan will build a large number of biogas digesters in the city, in addition to using the biogas produced to meet the heating needs of the settled population in winter, for those fermented organic fertilizers that can be recycled.

The soil layer of the grassland is too thin, and the bottom is full of sandy soil, which can also protect the grass from surface nutrients and soil erosion, but once you switch to high-yield crops, it can easily cause soil desertification. Because, without enough organic fertilizer as a supplement to the soil, it will not take a few years for the planted area to become a barren land.

Only this recycling and reusable model can feed more people and turn the barren grassland into a foreign Jiangnan.

Moreover, the establishment of this animal husbandry system will also help to control the entire grassland, which will affect and reduce the nomadic habits of all people, and force the migrated Han and conquered Hu people to do without the agricultural system.

When the time comes, they don't have to do it themselves, once those herdsmen rebel, there will be leaders who will press on their heads to run to suppress it because of the damage to their interests.

(PS: Some readers say that rural areas are not suitable for the use of biogas, that is because the population in modern rural areas is too large and the proportion of livestock is too small, coupled with the different food structure, resulting in insufficient combustible crude fiber and nitrogen-free extract in the manure, which is not as convenient as burning coal and gas, so that the biogas digester cannot be implemented.) In fact, a lump of dry cow dung can provide about 900 to 4,500 calories when burned, which is almost the same weight of honeycomb coal.... The latter has a combustion value of 4,700 kcal, which is more efficient when converted into biogas, so it is completely feasible to put it in the grassland with a large number of livestock. In fact, many pastoral areas in Inner Mongolia use biogas to generate electricity, and modern India exports cow dung on a large scale, and it exists as a trade in the countryside).