0 Cryptic Math

I know this is math, but what kind of math is it?  I found this problem worked out on my dry erase board.  It was so interesting that I had to take a picture of it before I erased it.  I'm assuming it has something to do with agriculture.  I'm basing this off the notations for corn and (I think) alfalfa.  Has anybody ever seen anything like this?  I'm just intrigued by it.