Those of you who are interested in history might enjoy taking a look at this interactive timeline of agriculture in the United States at It provides a list of agricultural innovations and societal changes and events that affected growing crops in the U. S., broken into five different eras from 1600 to the present. This includes the impacts of the different wars and slavery on agricultural practices as well as challenges like the effect of invasive species such the boll weevil. It also includes some periods of climatological interest such as the Dust Bowl and drought. There are a number of discussion questions that could be used as a study guide if this was used in a classroom setting, too.