Since farmers are most likely on colony worlds, instead of well-settled core worlds -- where I would think most of the agriculture would be automated -- planetary science makes sense. I would suggest that a farmer would have a lower planetary sciences (maybe a 1) and an administration 2 (federation), since the farm is mostly likely under official control somewhere down the line.
"War is an ugly thing but not the ugliest of things; the decayed and degraded state of moral and patriotic feelings which thinks that nothing is worth war is much worse. A man who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself."
John Stuart Mill