help farmers every step of the way, from fertilizing fields to removing weeds to harvesting crops. This encyclopedia gives readers a look at tractors, from the first steam-powered plows to today's self-driving, high-tech tractors. Features include a helpful introduction to the topic, a glossary, additional resources, and an index. Aligned to Common Core Standards and correlated to state standards. Early Encyclopedias is an imprint of Abdo Reference, a division of ABDO.