Final answer:
John Deere's accomplishment in the field of technology was the development of the steel plow, which revolutionized farming in the Midwest.
Step-by-step explanation:
John Deere's significant accomplishment in the field of technology was the development of the steel plow. In the early 1830s, Deere observed that the traditional cast iron plows used in the eastern states were not suitable for the tough, sticky soil of the Midwest. He experimented with different designs and eventually created a steel plow with a polished surface, which allowed it to easily cut through the soil and prevent it from sticking. This innovation revolutionized farming in the Midwest and greatly increased agricultural productivity.