"Hi~~~" Zhao Gao didn't dare to neglect and hurriedly set off to do things.

Li Yunze looked at Zhao Gao's hurried away figure, but didn't say much.

He took Ying Zheng out and said, "This is the icing on the cake. What really has a huge effect on increasing grain production is sufficient water conservancy and fertilizer."

As for one of the three major elements, he did not mention improved seeds. People these days also know how to make improved seeds from grains that look good and have plump grains.

"In terms of water conservancy, have you seen the construction of canals presided over by Zheng Guo?"

"So that Taifu will know."

Ying Zheng responded with a smile, "I have already been there and measured it using Professor Taifu's knowledge."

Li Yunze nodded, but he did not follow Ying Zheng's instructions and ask about the measurement results. Instead, he changed the topic to fertilizer.

"Chemical fertilizers mainly use chemical knowledge." Li Yunze imparted knowledge. "You already know about planting rotation and retting. The so-called potash fertilizer lies in the content of potassium oxide. It is difficult to prepare this stuff, but it is available in the Western Regions.

Natural potassium salt mines can be used to refine potassium salt using local methods."

Having said this, Li Yunze took out a book from his sleeve and handed it over, "This is the flotation method for refining potassium salt ore. You should learn it carefully. You will take the test next time."

"Hi."

Ying Zheng solemnly put the book in his arms.

"After we capture the Western Region, those salt mines will belong to Great Qin."

"Don't worry, Master."

Ying Zheng, whose eyes were full of confidence, immediately responded, "The Western Region will be the Western Region of Great Qin!"

"It's good to have such ambitions."

Li Yunze admired, and then turned the topic back to fertilizer.

"Phosphate fertilizer is difficult to produce chemically, mainly because Daqin's current technological level is too low."

"If it's natural, it would have to be the bones of fish, shrimp, birds and animals, ground into powder. But Qin doesn't have that much bone meal, so if you want it, you have to go to sea."

"Going to sea?"

"That's right, go to sea. There are many islands in the sea where seabirds gather. The guano they accumulate year after year is the best phosphate fertilizer, and the quantity is sufficient."

"Bird, bird droppings?" Ying Zheng paused unexpectedly. He had never thought that bird droppings could have such a use.

"The world is so big that nothing is trash."
Chapter completed!