I would guess the patch of rye has the most soil moisture under it.  It looks to be fully mature, and shouldn't be drawing much water.... if any.   The timing of the last rainfall event would influence this though.  The more recent the last rain event, the more likely the rye has more soil moisture under it. 

I would guess the corn has the least amount of soil moisture under it.  The corn looks to have the least amount of crop-canopy, and I also suspect the corn is at growth stage that it is taking in more water than the respective growth stage of the soybeans. 

Just guesses though, gordon