Well. let us see the resulting picture, please. That will tell a lot.
Was the wheat green and immature or was the wheat mature and yellow? That would make a difference.
My gut reaction is that green, immature wheat should be more like middle gray than the sky. Yellow wheat would be at least one whole stop lighter than middle gray. What this means is that I am guessing that your meter was inflated and caused you to underexpose the picture. Maybe not, let's see the pic.
My problem with some of these scenes is, that when there is really not a sufficient range of lights and really darks to meaure for an average, one must do some guessing to get things where one wants them. I'm not always really good at that,