Corn and Soybeans in the Same Field?

Big Data is collected during harvest

Roughly three years ago I inherited a small farm. Having grown up on this land I always remembered the people we rented it to rotating corn to beans year after year, but this year the farmer did something I was unfamiliar with. He planted corn around the wetland area and soybeans in the dryer areas.
While I can see the value of this particular planting scenario, I started looking at other fields as I traveled for work and I saw many single fields with both corn and beans planted next to one another.
In this post I’m looking for feedback as to the value of this method of planting? I can see if a farmer has 1000 acres where planting 500 of one crop and 500 of an alternate crop could hedge against an overly dry or overly wet year, but what is the reasoning behind the dual crop planting in a single field?