Rototiller

The rototiller stirs and pulverizes the soil, either before planting (to aerate the soil and prepare a smooth, loose seedbed) or after the crop has begun growing to kill weeds (controlled disturbance of the topsoil close to the crop plants kills the surrounding weeds by uprooting them, burying their leaves to disrupt their photosynthesis, or a combination of both). Cultivators are designed to disturb the soil in careful patterns, sparing the crop plants but disrupting the weeds.