"The farm bill provides an opportunity for Congress to address agricultural and food issues comprehensively about every five years. Over time, farm bills have tended to become more complicated and politically sensitive. As a result, the timeline for reauthorization has become less certain. With the exception of the 2018 farm bill, recent farm bills have taken longer to enact than in previous decades. Beginning in 2008, farm bills have been subject to various developments that have delayed enactment, such as insufficient votes to pass the House floor, presidential vetoes, or short-term extensions."
CRS Report for Congress, R45210
Congressional Research Service: https://crsreports.congress.gov/