A Graphic Summary of Physical Features and Land Utilization in the United States

Excerpts from the report: The physical conditions have been fundamental in determining the geography of American agriculture. These physical conditions became more important with the increasing commercialization of agriculture. The constant improvement in transportation facilities and the keen competition of producers in different regions make the production of a crop or animal product sensitive even to the minute advantages or disadvantages which a district may possess. They compel shifts in crop production or in use of land to be made with an alacrity unknown in the precommercial period. The control of the physical conditions over agricultural development, instead of being mitigated by the progress of science and commerce, has been intensified and enforced. These physical conditions may be classified into four groups: (1) Temperature and duration of the frost-free season (figs. 3-5). (2) Moisture, of which the seasonal distribution of precipitation and the total annual amount are important (figs. 6-10). (3) Topography, lay of the land, and degree and direction of slope (fig. 2). (4) Soils, which are influenced greatly in their development by climate and the natural vegetation (figs. 6-10).