How did john deere's steel-tipped plow change american agriculture?

Made it faster and more efficient--the plow allowed for quicker planting times and the steel made a more reliable product.

With the steel plow, farmers could rely on a machine that would hold up and not break as easily as iron or wood. The plow itself cut down on labor and made it easier for farmers to plow large plots of land. 

C.east asiais the answer.