We cut our first organic hay crop this week. Hay is a great crop to rotate with rice, because we harvest it in April, and still have time to plant a rice crop in May. Our hay is an oat/legume mix, and is headed for an organic dairy once we get it baled. To make hay, you cut the plants just after they have gone to flower using a machine called a swather. The swather cuts the plants and leaves them in a row on the ground, where they will sit for about a week to "cure." Once they plants are dry, the baler will come in and make bales. If you bale hay too green/wet, it will start composting in the bale, and potentially catch fire.
I'm using hay as the third crop in our rotation of rice, wheat, and hay. The more crops you can have in an organic rotation, the better your weed control and yields of each crop will be. Weeds are our biggest problem in rice, so we're hoping that extending our rotation will help. Plus I feel more like a real farmer rotating crops like farmers used to do!
Here's a brief video of the swather mowing our hay.