How did America produce technologically advanced farmers?

There is an interesting column in the new Economist magazine about American agriculture. I quote:

Rivals in other lands have sniffy theories about why America, a rich country, is so good at producing cheap food. They paint American farmers as pawns of giant agri-corporations, bullied by market forces to produce genetically modified Frankenfoods......... 

Foreign rivals are right about the power of market forces in America, but wrong to see its farmers as passive victims. Americans have thought differently about agriculture for a long time—and not by accident. Settled in a rush of migration, peaking in the 1880s, Nebraska’s prairies were parcelled out to German, Czech, Danish, Swedish and even Luxemburgish pioneers. From the start the plan was to convert Old World homesteaders to the scientific ways of the New World. As the system developed, Congress sent county agents from universities to teach menfolk modern farming and their wives such skills as tomato-canning. In the 1920s educational trains trundled through the prairies, pulling boxcars of animals and demonstration crops. At each stop, hundreds would gather for public lectures. 

Especially interesting is the role of children in disseminating new knowledge, attitudes and practices, as well as being prepared themselves as future farmers:

4-H was born to spread hard science as well as to shape character. Some 2m children attend the group’s clubs and camps, while millions more follow 4-H programmes in schools.