What is mouldboard plow?

A Moldboard Plow is a plow in a v-shape that is used to till under the soil. The spike of the V digs into the earth and the sides curl it under, so basically it takes the soil on top and moves it underneath. Moldboard are good to eliminate weeds but bad when it comes to erosion. Much of the destruction attributed to the Dust Bowl happened because farmers used moldboard plows time and time again and left the earth fallow during non- growing seasons.