If I recall correctly, there was a pic posted earlier this year.  Someone had planted strips of corn and soybeans - one planter width of corn, then one planter width of soybeans, alternating across the field. 

As I recall, the soybeans right next to the corn were shorter than the soybeans in the center rows - exact opposite effect of what you show.  If I recall correctly.

I would have said that the corn towering over the soybeans suppressed the soybeans.  At least that is what it appeared in that set of pics.

I don't recall who posted this pic, or approximately when. 

It just seems in contrast to what you are showing.

Perplexed ???