The harvest act would deny any path for citizenship to farm workers. Instead, even if they work year-round they would have no claims to citizenship. This means that laborers from other countries will never be citizens with the benefits of citizens.
Second the Harvest act would streamline the lie that farm work is accessible to citizens. Like Stephen Colbert testifying in congress. The Harvest act seeks to blame american workers for reason they aren’t working on the farm. Read Dan Rather’s piece here.