Sowing crops on a farm would be backbreaking working without the machines called planters. These tractor-pulled tools can look quite different. Some are small, sowing just one row, and some can plant as many as 48 rows at a time. Readers will find out how these machines work and see their parts in motion in labeled photographs. They ll also discover how technology is changing this farm machine as well as some other seeding devices. Full-Color Photographs, For Further Information Section, Glossary, Index, Infographics, Web Sites.