Technology did a great deal to change American agriculture during this time. Some of these changes made things easier for small farmers and some made it harder.
Technological changes in plows and other such machinery helped small farmers initially. New plows allowed them to till the heavier, more fertile soil of the Great Plains. New harvesters allowed them to cultivate more acreage.
However, technology also ended up hurting them. As machinery got bigger, it gave large farms that could afford and use the big machines an advantage. As railroads (another technology) became more and more vital to the farmers' livelihoods, the railroad companies were more able to abuse farmers by charging them high prices to haul their produce.
In these ways, technology helped American agriculture become more productive, but it also ended up hurting small farmers.