Initially it was called war time. And it was even used even in Europe from WWI through WWII. But post WWII most abandoned it. Including the United States. It had nothing to do with farmers. They’re actually one of the groups most against it.
It was standardized in the United States in 1966 at the behest of wealthy retailers who lobbied the government. Believing the extra hour of daylight correlated in some meaningful way to increased sales. It didn’t. But that was the rationale.
The most recent changes to DST, pushing it to the first of November. Happened in the late 2010’s. Largely pushed for by candy makers/retailers, again claiming it would boost sales and somehow be safer. (Halloween)