The steel plow was one of the most important agricultural machines of the 19th century because it helped farmers work land that earlier plows could not handle well. On the North American prairies, thick grass roots and dense soil often clogged or broke wooden and cast-iron plows. A polished steel blade could slice through this tough ground with less sticking and less drag.
This made it possible to prepare more acres for planting in less time.
Key Facts
- A plow cuts, lifts, and turns soil to prepare a seedbed for planting.
- The steel plow worked better in sticky prairie soil because polished steel shed soil more easily than wood or cast iron.
- Work done by a plow can be estimated by W = Fd, where F is pulling force and d is distance.
- If a team pulls with 900 N over 200 m, the work is W = 900 N x 200 m = 180,000 J.
- Power measures how fast work is done: P = W/t.
- Turning soil can bury weeds and crop residue, but too much plowing can increase erosion and damage soil structure.
Vocabulary
- Steel plow
- A plow with a steel cutting surface designed to slice through and turn heavy soil more efficiently than many earlier plows.
- Moldboard
- The curved part of a plow that lifts and flips the cut slice of soil.
- Share
- The sharp lower blade of a plow that makes the first cut into the soil.
- Furrow
- A long narrow trench made in the soil as a plow passes through it.
- Draft force
- The pulling force needed to move a plow through soil.
Common Mistakes to Avoid
- Thinking the steel plow was only sharper, when its smooth polished surface was also important because it helped sticky soil slide off instead of clogging.
- Assuming plowing always improves soil, which is wrong because repeated deep plowing can expose soil to wind and water erosion.
- Confusing the share with the moldboard, because the share cuts the soil while the moldboard lifts and turns it.
- Ignoring soil type when comparing plows, because a design that works in light sandy soil may fail or clog in dense prairie sod.
Practice Questions
- 1 A plow requires a draft force of 800 N and is pulled 150 m across a field. How much work is done on the plow?
- 2 A farmer using an older plow can prepare 2 acres per day, while a steel plow allows 5 acres per day. How many more acres can the farmer prepare in 6 days with the steel plow?
- 3 Explain why a polished steel moldboard would be better than a rough iron surface for plowing dense prairie soil.