1. too dry to farm
2. mid-19th century--rain follow the plow
3. after 1890 (earlier in some places)--we can turn desert in farmland by irrigation
   

• forests add moisture to the air
• if we cut down too much forest that will cause summer drought
• George Perkins Marsh believed that cutting forests would reduce the amount of rain
• so if we plant trees will that increase the amount of rainfall?
• if we plow the land more water will evaporate from the soil
• some people argued this would cause more rain
• there were a number of years of good rainfall 1878-1887 which encouraged this wishful thinking, then drought hit

photo credit David@UNT / Foter.com / CC BY-NC-SA
center pivot irrigation as seen from the air

even farther west, irrigation was clearly needed

• technology would allow us to transform barren land into a garden
• in the northwestern plains this was mostly individual wells and windmills

• in the southwest, first farmers banded together (following the lead of the Mormons) and invested in a private irrigation company
  
• the first story was that irrigation machinery would become cheap and then there would be plentiful water, but the real problem was the water supply
• where water supply could be well managed, some towns were successful, eg. Ontario, California
• in the 1880s and 1890s some larger water companies were established

Rise of big water companies and large farms replacing the small family farms
The money was in land speculation, at the expense of the small farmer

issues about irrigation:

• the wasteland can be turned into a source of food, land for farmers, a way to make money
• the desert has no value
• we can control the natural world through technology
• tension between a nation of small farmers and people who are looking to make money on  a large scale
  

Boulder/Hoover Dam film: http://www.youtube.com/watch?v=PSMDPzd11ek