Gu Zhao went home and entered the inner room first, sat at the desk, took a piece of paper with notes written on it, turned it over, and recorded it behind his back. He had to slowly sort out the fertilizers and find out which ones were suitable for mass production and had low cost.

　　There are many kinds of modern fertilizers, such as potash fertilizer, nitrogen fertilizer, and phosphate fertilizer. Forget about extracting these fertilizers, as they require utensils. A simpler option is ammonium nitrate fertilizer, which is simple. It only requires urine fermentation, adding raw gypsum powder, and then mixing them together and letting them ferment.

　　There is also urea fertilizer, which is also urine plus gypsum.

　　These two types are acidic fertilizers, suitable for alkaline soil and as topdressing for rice.

　　The main component of marble is calcium carbonate, which decomposes at high temperature to form quicklime. Quicklime reacts with water to form slaked lime, which is calcium hydroxide. Gypsum is slaked lime.

　　Marble is a natural mineral, so it should have existed in this era.

　　”Zhou Zhou, what does Uncle Wang use to make tofu?” Gu Zhao remembered that gypsum was used to make tofu.

　　Li Zhouzhou: “I don’t know. The skill of making tofu is inherited from the Wang family. No one in the village wants to know about it.” In fact, some people have asked about it. Uncle Wang makes a lot of money every winter just by selling tofu. There must be people in the village who have calculated the details behind the scenes. People may be jealous, but they will be scolded if they ask about it.

　　”My husband, is this related to the harvest in the fields?”

　　Gu Zhao explained to Zhou Zhou in simple words: “There are some connections. If the tofu is made with gypsum, urine must be added and fermented before it can be used. We will have to study the details together later.”

　　He knew the theory, but had never tried it in practice. He had to slowly try the proportions, otherwise the rice would be burned to death. He would rather have a lighter flavor than a stronger one.

　　”Is it difficult to ask?” Gu Zhao guessed, and said, “We only ask about gypsum, and we won’t secretly learn how to make tofu. Can you explain it more clearly?”

　　Li Zhouzhou: “Uncle Wang is a very good person, but his husband, Wang Ergou, is not a good person.”

　　Gu Zhao seldom heard Zhou Zhou express such disgust and hatred for someone, and he did not hide the expression on his face, which showed that Wang Ergou was really a piece of shit.

　　”But why does Uncle Wang have the last name Wang?”

　　Li Zhouzhou said: “Uncle Wang was picked up by Wang Ergou’s mother. Everyone in the village knows this. Later, the Wang family became poor and Wang Ergou couldn’t afford to marry a wife, so they let Uncle Wang marry Wang Ergou.”

　　This way you don’t even have to give any money for the bride price.

　　Seeing Zhou Zhou’s unhappy face, Gu Zhao moved his butt closer to the stool and asked Zhou Zhou to sit down and talk slowly. Li Zhou Zhou sat down and leaned close to his husband, saying, “Since I was a child, I have watched Uncle Wang busying himself with his daily life, and I secretly vowed in my heart that even if I don’t marry, I will never marry someone like Wang Ergou.”

　　Wang Ergou’s grandfather lived a relatively well-off life in the village, with many paddy fields and hardworking people. Later, when they married their sons, they built blue brick and tile houses, which were the first to be built in the village. The daughter-in-law they married was Wang Ergou’s mother, who was very beautiful and kind, and her family background was also very rich. She also passed on the tofu-making craft to her daughter and brought it into the Wang family.

　　Of course, the Wang family also gave a lot of betrothal gifts, a full six taels of silver.

　　When people in the village talked about it at that time, everyone praised Wang Ergou’s mother for her good marriage, the Wang family valued her, and she would enjoy endless blessings in the future.

　　”According to what you said, the Wang family’s life will definitely be neither good nor bad.” Gu Zhao talked to his wife. When chatting, it is necessary to have a supporting role, otherwise it would be very boring for his wife to just do the crosstalk alone.

　　Especially since Zhou Zhou from his family is not a person who likes to talk about such things, it is rare for him to talk about it and show his support.

　　Li Zhouzhou said, “I don’t know if I envy him. I hadn’t given birth yet. I just heard from my grandma that the Wang family was the best in the village. Otherwise, Wang Ergou’s mother wouldn’t have picked him up and raised him. No one in his family would have said no.”

　　That’s the reason.

　　Some families in the village have to tighten their belts on food to raise their own children. If there is a real shortage, how could they be willing to raise an abandoned baby?

　　It was not long since Wang Ergou’s mother had a miscarriage. She was going to the town with other people in the village. On the way, they heard a faint crying sound in a field. When they went to take a look, they saw a baby wrapped in a tattered swaddling cloth in the cold weather. They didn’t know how long the baby had been there, but his face had turned blue from the cold. If they didn’t take care of the baby, he would die.

　　Wang Ergou’s mother had just lost a child. She couldn’t bear to see such a thing, so she took the child to the town to see a doctor. The child was lucky and was saved, but he looked weak. When she came back, the villagers said that although the child was picked up, he was just a boy, and he only needed food. When he grew up and got married, he would get a dowry.