Explain how the railroad and irrigation turned California's Central Valley into one of the world's most productive farming regions.
Once the railroad connected California to the rest of the country, Central Valley farmers gained something they never had before: a fast way to get crops to faraway markets. Early on, huge "bonanza" wheat farms covered much of the valley in the 1870s and 1880s. Starting in the 1880s, the invention of refrigerated railroad cars let farmers ship delicate fresh fruit and vegetables all the way to eastern cities without it spoiling on the way, which pushed California agriculture toward the fruit orchards, grapes, and vegetable fields it is still famous for today.
Combined with the irrigation systems studied back in week 3, and the water projects coming up next week, the Central Valley grew into one of the most productive farming regions on Earth. Even today, California produces a large share of the entire country's fruits, vegetables, and nuts -- a direct result of the railroad, refrigeration, and irrigation working together.
Mastery looks like: They can explain how the railroad, refrigeration, and irrigation together built California's farming economy.
Common stumbles: Thinking California farming appeared instantly rather than developing through several connected inventions over decades.