Rice harvest is completely mechanized in the United States, and uses very large, very expensive machinery. Much of the rest of the world still harvests by hand or with small equipment. You can see some of this if you search YouTube. In our case, we use a John Deere 9760 STS with a "stripper header." When you watch the video, the header is the blue and white thing on the front of the combine. Stripper headers are a relatively new technology, which greatly improves the efficiency of harvest by stripping the grain off the plant and leaving the plant stem standing in the field. By contrast, the older style headers cut off the entire plant and feed it into the combine, which then separates grain from straw. This takes much more time and fuel.
Here's the video of the combine with a stripper header:
Here is a video of the combine dumping rice into a truck.
Here is a view from the driver's seat. It's not great quality, but you get the idea.