This looks like the perfect place for a picnic.

Getting to your question, I'd try two things:
1- Crop it in a 2:1 frame to accentuate the flatness and reduce the dominating sky
2 - Add the keywords "mustard, canola, panorama, panoramic, banner, horizontal, copyspace, pasture, pastoral, cloudy, farm, summertime, bright". I know it's a rape field, but it could also be a mustard or canola field, too.

... good luck!

"Canola"  there's no such thing as canola. Well, there is, but after kiling a bunch a people AGCanada changed the name.   It's a made up word for rapeseed by AgCanada  (CAN=canada, ola=oil)  Looks like mustard to me, not rapeseed.   If you're going to spam keywords, why not add, blue, yellow, green, money, wavy, plain, plane, insect, insects, weevils,  heavenly, sirene, snake, agriculture, bituminous, sandy, agregate, agate, etc, etc.   

I think it was just fine the way it is. A very nice picture.  Why it didn't click?  Look at the top 50 at shutterstock, there's a couple just like it.