In the busy New Year, the chapters of history quietly turned to 195, which was also the first year of Jian'an in this time and space.

Guoyuan's performance report at the end of the year finally brought Li Su a lot of difficulties:

For example, how difficult it is to grow cotton in Shu. Now, in order to solve the problem of "the waterwheels in the Chengdu Plain are idle in winter", Zhuge Jin and Zhuge Zhi must compensatory development of a certain amount of cotton industry in Yizhou to avoid wasting industrial resources.

The final discussion of this issue by Li Su and Guoyuan was to ask him to arrange for people to go to relatively dry Brazilian County to find areas with convenient irrigation and relatively dry climates to plant cotton.

In addition, cotton crops can absorb water quickly and the fields do not need to store water. They can carry valleys, rivers and slopes to plant rice without wasting the plains.

As we all know, in later generations, Shu was only around Chongqing, and the summer was hot enough without rainfall, and the Chengdu Plain was impossible. This arrangement can be considered as a full allocation of resources.

In addition to the problem of growing cotton in Shu, Guoyuan's second difficulty was that he discovered that "after planting double-season rice for two consecutive years, the ground abilities began to decline, and fertilization may not be able to be replenished."

This problem was impossible for the Han Dynasty to solve, because they had not squeezed the ground force so hard before, and they could not cultivate and apply a lot of fertilization like the Song Dynasty who planted double-season rice in later generations.

Linyi rice was introduced to Yizhou in just two years. In the first year, because the seed volume was less than 20,000 stones, the area of ​​planting was less than one county, and only a few counties. It was not until 194 that it was promoted to most rice-producing areas in Yizhou.

Therefore, those who have had the experiment experience of "continuous planting for two years" are roughly the military farming areas around Jiangyang County, Jianwei County and some counties adjacent to Lushui County, which are located in Zhuti County. Guoyuan can discover problems so quickly, which shows that his work attitude is still very meticulous, and he is closely monitoring the output every year in pilot fields.

If you change to an irresponsible military farmer, you will either place satellites and brag about it or report it alone, or you will not care about the yield. This will take a lot of time, and maybe in the future, people will reduce their yields due to illegal planting technology.

Therefore, regardless of whether the problem can be solved this time, Guoyuan discovered it in time and reported it in time. With this attitude, Li Su rewarded him with an additional 20 kilograms of gold, and said that he would explain Guoyuan's serious work attitude in the letter to Liu Bei at that time.

Then there is a specific solution. Li Su has no good solution, just relying on the general experience. He first proposed that "Once the ground abilities decrease, don't be busy with fallow and raising land. You can plant two-season rice for two years and take turns to plant one season of soybeans." After all, the nitrogen-fixing bacteria of soybeans can increase soil fertility, and Li Su still wants to get this common sense.

However, the yield of soybeans is low, less than half of the rice planted. Farmers will definitely lose money, so if they can, they won’t.

The second method that Li Su thought of was to let Guoyuan plant in those hillside river valley areas. For example, when Li Su organized Guoyuan to cultivate on both sides of the Jialing River and Lushui River a few years ago, they planted rice along the river with long low-lying and flat irrigated land, and planted tea trees and radishes on uneven high slopes.

Now, some of the less flat radish fields can be converted into soybeans. After the harvest season, the soybeans are harvested, and the remaining plants are tilled and dug out, and then piled up and burned them together to transport the wood ash to the rice fields for fertilization. If the transportation capacity is convenient, drag the bean plants completely into the rice fields before burning.

Guoyuan has planted fields for many years, and of course he also knew that planting beans might make the fields more fertile, but he had only worked on "after turning the planting, he directly plowed the remaining beans into the soil to fertilize the fields for the next season of crops." As for the fertile fields in other places mentioned by Li Su, he didn't seem to have any good impression of them.

After listening to this suggestion, Guoyuan defended: "I have tried these things, I have also tried to use my illness and try to pour the ashes of burned bean rods or chopped bean rods into the rice fields. But the effect is always not as good as ploughing the fields."

Li Su thought for a while and reminded: "It is better to move fertilizer than to plough the fertility in the raw fields, which means you have not done it thoroughly - you also said that you asked the villagers to harvest the bean pods and pile them into the rice fields. You didn't dig away the most precious bean roots. The fertility of the bean plant is probably mostly in the bean roots."

Of course, Li Su knew in his heart that the key is that the "rhizobacteria" of legumes can fix nitrogen, so if the straw is harvested without digging the roots, the effect will be poor. But she must use language that Guoyuan can understand and cannot rashly mention the professional terms "rhizobacteria, nitrogen fixing bacteria".

Moreover, since rhizobia may survive after the beans are harvested, it is definitely better to plow the bean roots directly and remove them than to burn them into wood ash. As long as the nitrogen fixing bacteria are alive, they can always fix more nitrogen.

So Li Su also reminded Guoyuan: Then, burn the straw into wood ash and fertilize it, or uproot the bean roots and compost it together. Don’t dig out the bean roots in one fell swoop and then burn them to fertilize them. That would be a waste of resources.

Although Guoyuan didn't know the scientific principles, it was rare for Jun to brainstorm and help him find a solution. Of course, he had to write them down. Even if Jun was not professional, Guoyuan had this string in his mind, at least he could do a control group experiment after going back. After a year, he would know how big the difference between "burning the bean roots and fertilizing the bean roots" and not burning the fertilizer.

The method discussed by Li Su and Guoyuan was tailor-made for Shu with complex terrain. If it were placed on the northern plains, there would be no need to make such a lot of trouble. It would be impossible to have so many complex environments where "there are paddy fields next to the mountain fields". The rotation of the mountain fields and the beans are used to exchange for flat fields and continuous high-intensity double-season rice planting in paddy fields.

After solving the problem of the rotation of seeds and bean nitrogen fixation fertilizer, the only thing Li Su could remedy was fertilizers, but the idea of ​​"fertilizer" flashed through his mind, and then he felt ridiculous - he knew completely that in a dynasty without chemical industry, it would be better to find a way to create muskets and cannons.

But just when he gave up, as he was cautious in nature, he still discovered some useful ideas: it is impossible to synthesize chemical fertilizers, but if there are ingredients in natural minerals that can be used as fertilizers and they are going to be separated and there is no other use, then you can find a way to turn waste into treasure.

After thinking about it, there are two ways to use your brain. The former is a bit far away, while the latter is convenient, but the output is dropping, so there is no need to do it uniquely.

He said to Guoyuan: "As far as I know, the ancients knew that bird stones on the island could be fattened in fields, and such minerals were mentioned in "Shan Hai Jing". In the future, to solve the problem of fattening in fields in the long run, we must develop Jiaozhou and find deserted islands without trees overseas, especially to ensure that there are few trees, so that there are many people who accumulate bird droppings and turn into stones for tens of millions of years.

"Shan Hai Jing" says that Zhuya and the small islands around Yizhou have many such things. If the sea ships are transported conveniently, they can be given to the people of Jiaozhou and Yangzhou in the future. But it is forgot to transport them to Yizhou, but it is not enough to transport them to Yizhou. The pickled goods that cross mountains and ridges are not available.

However, the peat used in our iron and porcelain kilns will also emit some odor when refining coke. Shanhaijing says that these odors can also be fertilizer. In the future, the peat coking plants in Jiangyang County will all let the waste gas be adsorbed through water when venting waste gas, or sprinkle wood ash and other acid salts in the water. In short, try it slowly and see what is cheap and easy to absorb coking waste gas.

The vegetation ash water that absorbed waste gas was sold to the people of double-season rice planted in Jiangyangdao and other counties at a low price to help them fertilize the fields."

The waste gas for coal coking mentioned by Li Su is naturally mainly ammonia, and after absorption, it is also considered a type of nitrogen fertilizer. Of course, if sulfur dioxide is burned from coal, it doesn’t matter. At most, it can form very dilute sulfuric acid. Sulfuric acid then forms ammonium sulfate or ammonium sulfite with ammonia, which is also directly used as nitrogen fertilizer.

However, the fertilizer separated by this natural mineral species is much lower than that of chemical synthesis. Nowadays, the iron smelting industry in the two counties consumes at most one or two thousand tons of coal every year. In addition, the coal industry for burning porcelain and bricks, the total consumption will not exceed 5,000 tons. It is good if the impurity ammonia gas can collect hundreds of tons a year, and it will also consume it. In the end, it will definitely not exceed more than 1,000 tons of nitrogen fertilizer.

According to the amount of dozens of kilograms per mu in later generations, the amount of 10 kilograms per mu is equivalent to 100 kilograms per mu, and a ton of nitrogen fertilizer is only enough for 100 kilograms of rice fields in Jiangyangdao.

Of course, the land and land fertility in later generations has been drained. After all, this era has just begun to squeeze out, and the effect of applying fertilizers will be better. Moreover, it is not that you will not apply farm fertilizers after using fertilizers. This is just a supplement. After this calculation, it is still possible to use mixed with farm fertilizers and subsidize 500,000 to 600,000 mu of rice fields, which is only one or two counties, which is only enough for agricultural production in Jiangyang and Wudao County, and cannot be transported out.

It's also a small supplement.

...

After concentrating all the difficulties encountered by Guoyuan, Li Su asked him to arrange them as soon as possible and asked his trusted officials to start conducting control experiments this year. He should try not to fall behind all the fruits of komizing gas and bean roots.

After the arrangements, Li Su instructed Guoyuan to prepare to follow a group of people who immigrated to Liangzhou after he was about to organize after the spring plowing. This year, he will first go to Dazhong in Wudu County to farm, adapt to the environment, and try to grow cotton in the northern environment, and next year, he will also plant cotton in the Hexi Corridor of Liangzhou.

Guoyuan was very confused about Li Su's idea of ​​"fearing a population explosion in Shu", but after all, he was just an executive officer and had to do it if he didn't understand, so he was still very diligent in arranging his subordinates to organize spring farming and farming, and arrange various experiments explained by Li Su.

Li Su also knew that the Guanzhong area had a major disaster last year, so there was insufficient surplus grain. Try not to immigrate to the north too early before this autumn grain harvest this year. Although the Tianshui area in Longxi was not as miserable as Guanzhong last year, it was not much better.

So Li Su's plan is to send a group of completely landless immigrants from the Chengdu Plain this year to Dazhong after the busy spring farming season, arrive in about April, and then plant summer grain and cotton. In this way, as long as the local grain is stored, they will survive the green and yellow harvest. After the harvest is harvested in September, the summer grains grown by the people can be returned. The insufficient part is transported from Chengdu to the north. As long as the total amount is not large, it will take Zhuge Liang's old road to Tianshui six times to go to Qishan and Tianshui. It is not too difficult to transport.

Moreover, by then, Guan Yu and Ma Chao had already used troops to Guo Si, and they could also use food to part of the enemy. For the Qiang people in the Hetao area, Li Su would not regard them as his own people until they were convinced and surrendered to the court. They would rob them as their own people, and would rob them as they should.

——
Chapter completed!