Sky Curtain: My Great Qin must have an aircraft carrier!

Under the watchful eyes of everyone, the celestial curtain finally began its explanation.

The image shows golden wheat, shimmering brilliantly in the sunlight.

Before discussing ammonia synthesis, let's clarify one question: how much grain could ancient people actually grow?

Taking the Qing Dynasty, the pinnacle of agricultural civilization, as an example, after the widespread promotion of high-yield crops, the yield per mu was approximately 250 to 300 jin.

With this output, the Qing Dynasty fed 400 million people, which was the ceiling for human agriculture before the industrial age.

"How many? Four hundred million people?"

Upon seeing this number, Ying Zheng was somewhat lost in thought and checked it several times.

Although he didn't particularly like the later dynasties, he was still shocked by this number!

When the Qin Dynasty unified the six kingdoms and registered all the people, the population was only a little over 20 million.

What kind of monster was the Qing Dynasty?

Ying Zheng looked at Li Si, a strange tightness in his chest: "Li Si, what is the current yield per mu in Qin?"

Li Si bowed, thinking that they had finally asked about his area of ​​expertise.

He went over it in his mind several times before replying in a deep voice, "Your Majesty, the fertile fields of Guanzhong are the finest in the land, yielding approximately ninety jin."

Ying Zheng raised an eyelid, feeling inexplicably displeased.

The country he painstakingly built, even with the people working diligently for a year, was still not worth a third of what it was during the Qing Dynasty.

Could it be that the Qing Dynasty possessed some kind of magical power that could conjure up food from the ground?

"Very well, I'll learn the method for achieving a yield of 300 jin per mu first, and we can talk about ammonia synthesis later."

Inside the Weiyang Palace, Liu Che stared blankly at the sky for a long time.

He knew the population of his dynasty well; at most, it would only be thirty million.

It's not that we don't want to raise more, it's that we don't have enough food!

If the yield per mu could double—no, even just an extra fifty jin—he would have taken over that place in the northern desert long ago.

"Since it's said to be before the Industrial Age, then I should be able to learn it, right?"

After a brief moment of thought, Liu Che ordered more people to be added to record the contents of the sky screen.

Food is so important that no monarch can afford to ignore it.

Just as emperors of all dynasties were filled with envy, jealousy and hatred towards the Qing Dynasty, Lu Li always felt that something was wrong.

"Hey, where are my comments?"

He casually tapped the screen, and text immediately floated across the right side of the sky.

(The high yield per mu in the Qing Dynasty was probably due to the promotion of American crops; otherwise, there wouldn't have been much difference compared to previous dynasties.)

(It still has to be the three crops: corn, potatoes, and sweet potatoes. As long as you find a decent plot of land, a yield of 1,000 jin per mu is not a problem. The key is that it is not too picky about the location; it can be grown even in the mountains.)

(There's also double-cropping rice, but it's not much different without chemical fertilizers. High-yield crops can't do without chemical fertilizers.)

(Multiple types of beans are also acceptable, but synthetic ammonia was still too advanced for ancient times.)

The barrage of comments floated across the sky, and everyone, across countless dynasties, saw these words simultaneously.

American crops?

These four words made all the emperors prick up their ears.

Ying Zheng frowned. "What do you mean by America?"

Liu Che pondered this, and a thought struck him: Should crops be introduced from foreign lands?

Zhang Qian brought back grapes, alfalfa, and pomegranates from the Western Regions back then; this method is feasible!

The main reason why the Qing Dynasty was able to achieve this level of grain production was the promotion of corn, potatoes, and sweet potatoes.

These three crops originated in the Americas and were brought to Asia by Western navigators, where they were gradually cultivated on a large scale in the Central Plains.

Their common characteristics are: drought resistance, tolerance to poor soil, and high yield, making them particularly suitable for promotion in mountainous and arid areas.

In addition, the Qing Dynasty also popularized double-cropping rice on a large scale, and with this combination of measures, it fed 400 million people.

It can be said that before the Industrial Age, no civilization could produce more output than the Qing Dynasty.

"uh-huh."

Kangxi leaned back on his dragon throne, a slight smile playing on his lips, quite pleased with Tianmu's praise.

Years ago, the Governor-General of Fujian and Zhejiang submitted a memorial mentioning that sweet potatoes are drought-resistant and easy to grow, so he issued an imperial edict ordering all provinces to try planting them.

Little did anyone expect that this casual move would become the key to feeding 400 million people in the Qing Dynasty.

Over all dynasties, who could possibly reach the edge of this number?

However, after the initial joy, Kangxi's expression turned cold, and a shadow fell over his brow.

After the peak comes the decline.

The ceiling clearly states that this is the ceiling from before the industrial age.

No matter how much land the Qing Dynasty had, it could not support an endless population.

"The Americas—these so-called three pieces all come from there. Could it really be some kind of paradise?"

A thought suddenly occurred to Kangxi.

The Qing Dynasty has basically reached its limit in this land, so why not go and take a look at the Americas?

Since such a miraculous crop can grow here, the land must be vast and fertile.

We could try hiring Western ships and letting the Qing cavalry set foot on that land. Wouldn't that create another Qing dynasty?

At this moment, when Yongzheng saw the content on the sky, his face did not show much expression.

He simply placed the vermilion imperial brush in his hand on the brush mountain and exhaled a long breath of turbid air.

"The poll tax was merged into the land tax, the extra tax was returned to the public treasury, official corruption was rectified, and land reclamation was encouraged..."

Emperor Yongzheng muttered to himself, recounting all the measures he had taken since ascending the throne.

He worked from dawn till dusk, exhausting his energy, all for the sake of a few more bushels of grain and a few fewer people starving to death.

"Zhang Tingyu, what are the approximate yields per mu for each province recently calculated by the Ministry of Revenue?"

Zhang Tingyu respectfully reported: "Your Majesty, the yield per mu of the best fields in Jiangnan can reach more than 300 jin, while in the dry land of the north it is about 200 jin."

Yongzheng narrowed his eyes, having already made up his mind.

Two hundred and fifty jin is still some distance from the three hundred jin that Tianmu mentioned.

This means that there was still room for improvement in agricultural production during the Qing Dynasty.

The imagery on the screen mentioned corn, potatoes, and sweet potatoes.

Sweet potatoes are grown extensively in the south, while potatoes have gained some recognition in the northwest.

As for corn... he vaguely remembered that the Shandong governor had handed him a memorial a few days ago.

It is said that some people are growing something called "baogu" (包穩), which is extremely drought-resistant and flood-resistant. Could this be the corn that Tianmu was talking about?

Since that's the case, it can't be treated as a minor local skirmish.

"The imperial edict was issued to the Ministry of Revenue, and to the governors and viceroys of all provinces, ordering them to vigorously promote the planting of these three crops within their respective jurisdictions."

"The government stepped in to collect superior seeds and taught the people how to plant them."

"Anyone who shirks responsibility, is negligent, or shirks their duties will be severely punished!"

Zhang Tingyu bowed and accepted the order.

Looking at the mountain of memorials piled up on his desk, Emperor Yongzheng knew that the foundation of the Qing Dynasty lay in the farmland.

As long as the granaries are full, no matter how many rebel groups there are, they cannot cause any trouble.

Inside the Yuanmingyuan, the sounds of opera from the stage all ceased.

Emperor Qianlong stood on the steps of Jiuzhou Qingyan, his smile revealing his back teeth.

"Four hundred million people! Hahaha, ancestors above, your grandson has done it!"

"What limit? I am the limit! My achievements are unprecedented and will never be surpassed!"

What were Qin Shi Huang and Emperor Wu of Han compared to them? What were Emperor Taizong of Tang and Emperor Taizu of Song compared to them? How many people did they rule over?

The Qing Dynasty supported 400 million people, a feat unprecedented and likely to remain so.

And I have done it! I am the greatest emperor of all time, the only true dragon in the world!

Heshen, with great tact, knelt and kowtowed, shouting "Long live the Emperor!": "Your Majesty is wise! Such unprecedented achievements should be inscribed on stone and praised for all eternity!"

"Well said!" Emperor Qianlong was overjoyed. "Issue my decree to immediately proclaim this to the world and inform the thirteen provinces of this magnificent miracle."

"And those high-yield crops that Tianmu mentioned, what's with all this talk about America? Do those barbaric places even deserve to be called that?"

"From now on, corn, potatoes, and sweet potatoes will all be renamed Qianlong Crops."

"Let the governors and viceroys of all provinces expedite the promotion of this policy in the mountainous regions, so that every bite of food eaten by the people of the land will remind them of my benevolence."

Heshen kowtowed repeatedly in praise, flattering him resounding loudly.

Emperor Qianlong threw his head back and laughed, feeling that he had reached the pinnacle of his life.

He completely forgot about the industrial age and synthetic ammonia.

I have already done my best. What use are those barbarian tricks and ingenuity?