Ten acre field of mowed hay. We mow around the outside edge of the field and work our way in, leaving concentric swaths of cut hay.
This is the front view of the haybine which cuts the hay. Its power comes from a tractor which is ahead and to the left of the haybine.
This is the rear view of the haybine where the hay is thrown out in a swath. We can control the width of the swath by moving a sheet of metal up or down.
The sickle goes back and forth quickly, while the tines on the reel pull the hay towards the sickle. The sickle is made of individual blades which can be changed if they are damaged. The large metal points in front of the blades are called rock guards. They can be changed if damaged as well.
This haybine is called a mower/conditioner. The conditioning is performed by these two rolls. The hay is crushed as it passes through the rolls, allowing the stems to lose moisture faster. This helps with alfalfa, but isn’t necessary for grass.
Curiousfarmer 
Great post. Growing up in Texas, I was always curious about this process.
A short video clip showing the haybine in operation would be helpful.
Hmm, ten acres, eh? About the right size for a 10-hole frisbee golf course.
Takes me back to when I was a kid, baling hay in Iowa. When I was doing it, it was a three step process: mowing, using a sicklebar mower; raking; and baling. This was before the days of the giant round bales, so we had to hump 75 lb bales 5 or 6 high off the baler onto the flatbed wagon trailer. I was SO glad when I was promoted to driving the tractor.
Mowing was the best part, all by yourself in the sunshine, listening to the radio over the roar of the barely muffled tractor. Too bad it was over so quickly, only an hour or two for most hay fields.
Thanks for your comments!
UW-Platteville has an excellent disc golf course through prairie and wood. Much better than a hay field.
I found a video on youtube of a haybine in operation: http://www.youtube.com/watch?v=vMi8votH3C8
great pics! I’ve only ever driven the tractor as the bales were hoisted onto the trailer. you know, the old style rectangular kind.