We feel like a broken record. The land, the land, the land. Maybe we should try a different word. Dirt, maybe? Soil? How about terra?
The novel is titled The Good Earth because the earth is good. Yep. Pretty simple.
Everything in Wang Lung's life comes from the earth: the farmhouse, the oven, even the little earth gods. When Wang Lung gets rich, it's no coincidence that its jewels and not coins that make him rich. Where do jewels come from? That's right: the earth. So we can definitely say that the earth has been "good" to Wang Lung.
Near the end of the novel, Wang Lung starts thinking that the earth is evil and only wants to cause suffering. But all the suffering in the novel actually comes when Wang Lung is separated from the earth—and from the two other people closest to it, O-lan and Ching. That's the cause of the whole Lotus fiasco, of the constant bickering of his sons, and of all the other drama in the novel. It's not the earth's fault if Wang Lung wants to do his own thing.
One last thing. Notice that the title isn't Wang Lung, or The House of Hwang, or even The House of Wang. It's The Good Earth, and the earth will continue to be good long after they are all gone. Buck is interested in people, but she's also interested in how they fit into the big picture. The title never lets us forget that the book isn't just about Wang Lung; it's about how Wang Lung interacts with the earth.