I think this is great and have looked at it a number of times know. The angles and tones, and the 'focus' on the hands. I don't know if I would prefer more detail on the head or not? Doesn't matter though, this is good.
I like how you can easily recognize every element, even though everything is of similar shades of brown. And of course, the farmer lacking his head adds that extra touch of the macabre (for some reason it puts me in mind of The Adventures of Baron Munchausen and the King of the Moon character). This is through your greenhouse plastic, is it?