It gives farmers that extra hour of sunlight for working. (main reason)
Studies have shown that it reduces the amount of traffic accidents in the evening since there is still daylight.
edit: Here, just read this. It has a lot of information regarding it:
http://en.wikipedia.org/wiki/Daylight_saving_time
I agree that it can be annoying, but I know there are a lot of benefits and reasons for it; I had to do a research paper on DST in high school :awe:
That's the stupidest thing I've ever heard. Farmers don't go by the clock. If they didn't have DST, they would just adjust their working hours to work during the available daylight. It's not like they are bound to a 9-5 deskjob. They work whatever hours gets the job done.