what happens when scool lets out? why is this a big deal?

Papa has still not left for the railroad when school ends. When Cassie begs him to stay he tells her he has to go in order to pay the taxes and mortgage. They have planted extra cotton to make up for the fact that Mama was fired. Just then, Mr. Avery arrives and says that he cannot buy things in Vicksburg anymore because Mr. Granger and Mr. Montier have asked their tenant farmers for sixty rather than fifty percent of their cotton and has threatened to kick those who shop in Vicksburg off their land. The Wallaces have threatened to get the sheriff to put those who owe debts on the chain gang. Stacey is angry after he leaves but Papa says that he does not understand the risks that Mr. Avery must face. When Cassie worries that they are giving up, Papa compares them to a little fig tree on their property. It is smaller than the other trees but keeps on doing what it has to do and does not give up.