In Chapter 28, the reader is informed about all the crops that will go in that season on the Baxter's farm. Penny is preparing the ground for tobacco, cotton and various other crops that they will put in as soon as the time is right.
But corn is by far the most important crop and is given more land that spring. It is vital because it is feed for the chickens, for the hogs, for the cow, and for the Baxters themselves. If they run short of corn, they have no chance to get ahead of the constant demands their livestock and their own lives place on them. Penny decided to plant extra corn in the hopes that they might get themselves a little farther away from the edge of starvation and ruin, a very real possibility in their situation.