Why is tilling bad for the soil?

The effect of tillage on soil

However, tillage has all along been contributing negatively to soil quality. Since tillage fractures the soil, it disrupts soil structure, accelerating surface runoff and soil erosion. ... Without crop residue, soil particles become more easily dislodged, being moved or 'splashed' away.

What is the purpose of Rototilling?

A rototiller is a powered garden tool used to loosen soil prior to planting and to keep pathways and nonplanted areas aerated during the growing season.