expression, godan verb (-su)
plow a field; plough a field
Refers to the agricultural act of turning over the soil in a field, typically in preparation for planting.
春になると、農家は畑を起こして種をまく準備をする。
When spring comes, farmers plow their fields to prepare for sowing seeds.
耕す is a more general verb for tilling or cultivating land, while 畑を起こす specifically refers to the initial plowing of a field.
Compound of 畑 (field) + を (object marker) + 起こす (to raise, to turn up). The verb 起こす here means to turn over the soil, bringing the lower layer to the surface.