In the base acre reallocation tool, wheat might be the planted crop. Soybeans would be listed as the subsequent crop, reflecting a second crop on that acreage. If you had a 100 acre wheat base, and a 0 acre soybean base, the calculator reallocates the base (if desired) as 50 acres for wheat and 50 acres for soybeans. Your choice whether to reallocate depends on your expecations for more payment benefits from the wheat and soybean combination than just the wheat base.