Not sure that we're operating on the same definition of "backpacking" here, it's just low cost travel[1]. On certain visas in Australia you can extend the duration by working in a specified area[2], which is where that form of travel intersects with the food production issues.

[1] https://en.wikipedia.org/wiki/Backpacking_(travel) [2] https://immi.homeaffairs.gov.au/visas/getting-a-visa/visa-li...

I strongly suspect that it might be their flavor of our "traditional" migrant workers that involved some temporary work visa.