Agriculture of America





Contents



The Rainfall
The Temperature
The Plant Life
The Corn Belt
Farm and Village
Diversification
1. THE RAINFALL

In the Northern Hemisphere, the western portions of continents are
especially favored by the prevailing winds. This is because the western lands
gather the rains as they come off the ocean, blown by storms that circle from
west to east.
Unfortunately, the Cascade Mountains and the Sierra Nevada Mountains, so
dose to the west coast, catch the largest share of the rain off the Pacific
Ocean before it can go further Inland. As a result, there is too little rain for
almost the whole western half of the United States, which lies in the ,,rain
shadow” of the mountains. In a great part of that territory, therefore,
farmers must depend on irrigation water from the snows or rains that are trapped
by the mountains.
One of the most important geographic boundaries in the United States 15 the
50-centimeter rainfall line, which runs north and south almost through the
middle of the country. East of the line, farming is relatively easy, and the
population is relatively large. West of the line, one finds man-made irrigation
systems, dry-farming, grazing, and fewer people. West of the Rocky Mountains,
running all the way from the Canadian border to Mexico, there are vast areas
where almost no trees grow. In this section of the country are the deserts which
receive as little as 12.7 centimeters of rainfall a year. Yet, west of the
Sierra Nevada Mountains, there are places in which 250 centime...