The real reason, of course Cai Dao knows, isn't it nitrogen-fixing cyanobacteria?

This is where Cai Dao is cunning, once it comes to scientific issues, he pushes the problem onto his unwarranted master, involving the occult, and it is naturally difficult for others to continue to ask, even if he is an official.

Now in the Qinzheng Palace, except for the blind Zhao Mi, everyone can see the expression on the crown prince's face at the moment, a little angry, a little helpless, and a little unconvinced, "Then why don't you plant soybeans on all those lands?" Also What does this test field mean? ”

"Emperor, you have asked four questions! I know the answer to the first question. By the way, Ur, do you know the answer to the first question? ”

"Father! Is it because of the problem of yield per mu? Zhao Mi didn't expect Song Shenzong to ask himself, but he still mustered up the courage to answer. This word was naturally learned from Cai Dao, and he was not very confident in this answer.

However, as soon as Zhao Mi said the words 'yield per mu', Song Shenzong and Cai Dao were a little surprised, but they didn't expect Zhao Mi to really be able to say the most correct answer.

That's right, it's a matter of yield per acre. Soybeans, although there is the effect of fertilizing the field, but the yield per mu of this crop has not been high, in the later generations when Chinese agriculture has been very developed, the yield of soybean per mu is less than 500 catties on average. Compared with the yield per mu of rice and wheat, this is too bad. If you give up the higher-yielding wheat or rice just to fertilize the fields, the result will definitely outweigh the losses.

In the Great Song Dynasty, the territory was already narrow, and the possibility of fallow was very small, and the wheel change was the most reasonable solution to the lack of land in the north.

Seeing that Zhao Maid was still very confused, Cai Dao took the initiative to explain: "One acre of soybean planting can harvest roughly one to two stones, but rice and wheat are different, one acre can harvest four or five stones. If soybeans are planted alone, the fields will be fertile, but what should the people eat at that time? Therefore, if you want to plant soybeans and restore soil fertility, you can only use the method of rotation. In this way, food is obtained, and the land is not delayed in the next year. ”

"As for the meaning of the test field. In fact, it is a measure taken because of the lack of capacity of the poor road. Poor Dao grew up in the south, and when he was in Xiaocili, he only grew rice, soybeans, and some vegetables. The habits of food crops such as winter wheat, corn, and sorghum are not understood. Applying manure to the field can also increase soil fertility and increase yield per mu. However, how to properly grow winter wheat and corn on one acre of land is not known to the poor. ”

So that's the case, this time Song Shenzong and his two sons understood it.

"So how should you test it?" This time, it was Xiao Zhao who asked, and he stayed with Cai Dao for a long time, which made him want to know everything about this magical peer.

"It's not complicated to say, but it's not easy. The key to the test field lies in the word experiment. This is, of course, nonsense! Speaking of this, Cai Dao deliberately said a cold joke, but he didn't expect that the three people in front of him had a low laugh, and they were all amused by him.

After the three of them had laughed enough, Cai Dao continued: "For example, how many seeds should be sprinkled in an acre of land, how deep each seed should be buried, what should be the interval between each seed, and how much fertilizer should be sprinkled per acre. These need to be recorded, and both the process of fertilizing and irrigating the field will take a long time to operate and record, and it will not be until next autumn harvest to finalize the best planting method. ”

Last but not least, Cai Dao deliberately paused before saying, "Also, some fields will not continue to fertilize in the process of planting winter wheat. ”

"Why is that?" Cai Dao said this a little strangely, and Song Shenzong asked casually.

"Your Majesty, the reason is actually very simple. In other parts of the Central Plains, the people in the countryside do not have as many people as in the cities, and they do not have many livestock, so they naturally do not have so much fertilizer to fertilize the fields. Therefore, fertilizing the fields does not make much sense today. At most, it is just to benefit a few powerful people. ”

"However, Your Majesty, you need not worry. Just selecting good seeds, planting and sowing seeds reasonably and effectively in each mu can increase the yield per mu. The nursery was actually used for experiments. The reason why Poor Dao asked for such a large area was to let others see the actual effect. Because the larger the size of the land, the more pronounced the shock effect of the harvest moment. If the poor road is only planted in small plots, others will not be convinced. ”

"If that's the case, Your Majesty, will you still trust Poor Dao?" Cai Dao's last sentence seemed to be asking Song Shenzong, but in fact, they already had an answer in each other's hearts.

If there was no significance for actual large-scale promotion, how could Song Shenzong be so fond of a six-year-old child like him?

"That's good! Hurry up and do this, kid! Song Shenzong naturally knew in his heart that what Cai Dao said was the truth. But he couldn't say it so bluntly in front of his two sons, so he wanted to get rid of this hateful boy at once.

"Your Majesty, before you go, I'm sure you're going to do something! Some of the little eunuchs you assigned to the nursery were too few. If next year's winter wheat harvest and autumn harvest are also successful, then if you send them to various places, such a small number of people will not be enough to distribute. Moreover, whether it is a little eunuch, or a child of the forbidden army or a military general, the status is too low. When it comes to the locality, can those governors and county magistrates who are civil officials listen to them? ”

"According to Poor Dao's observations in Shuibo Liangshan this time, there is a good chance that the civil officials in those places will not take care of them. Your Majesty, this is not something that has been closed before, even with your holy decree, many officials will act in a disobedient manner. What's more, maybe there will be a civil official like Han Qi at the beginning, who will kill the people you sent down as he wants. ”

"If the person who is killed is really guilty, that's it. However, if the two sides are only at odds, and the other side is unwilling to have a eunuch or military minister dictate in agricultural matters, then the dead man will not be very wronged. Just for the sake of a little eunuch, the son of a forbidden soldier, or the son of a military minister, would you kill that Wenchen? Even if he's just a small Jiupin Zhi County! Moreover, your will does not necessarily bind the civil servants below. ”

"Enough!" Shi Deyi listened to Cai Dao's more and more outrageous words, and drank in a low voice.

"Shaft, dare! You ......" Xiao Zhao couldn't help it, stood up from her embroidery pier, stepped forward and pointed at Cai Dao's nose, trembling with anger.

Originally, Song Shenzong was also very angry, but as soon as Shi Deyi and Xiao Zhao jumped out like this, he calmed down.

"That's it! Stand down, all of you! Song Shenzong spoke out to stop Shi Deyi and Zhao Maid, and waved everyone else in the Qinzheng Hall out.

When he stayed alone in the main hall, Song Shenzong couldn't help but think of Song Renzong.

This sage who was called an emperor or not, after so many years, Song Shenzong already had some doubts about his original judgment.

This is still the person around him, although he knows that Shi Deyi and Zhao Maid's actions just now are to maintain their majesty. However, if he, the emperor, was really powerful, how could Shi Deyi dare to speak out?

All this is because of the emperor he once worshipped, Song Renzong.

In the final analysis, Song Renzong was too arrogant to those civil ministers.

Cai Dao's words really hit the nail on the head.