Lan Ruozhu froze, asking, "You can extract oil from rapeseeds?"
He did not know much about farming, even though he had read about it. However, the books did not have enough information in that era. He had wanted to learn more about agriculture—the more detailed, the better.
Lan Ruozhu knew the most critical reason for farming was to feed the people.
His sister's short explanation allowed him to understand many things. Still, he wanted to hear more. He asked curiously, "Don't people usually use peanuts for oil?"
Su Binglan explained, "People only focused on using peanuts for oil because they hadn't discovered rapeseed. Although rapeseed oil isn't as fragrant as peanut oil, the yield from the former is much higher than the latter.
"That means people can use less land to harvest just as much oil from rapeseeds than peanuts. The Su Teng villagers planted many rapeseeds last year. Some of the seeds are almost ripe now."