The Relation of Climate to the Geographic Distribution of Crops in the United States

Abstract

A study of the agricultural statistics collected by the Bureau of the Census, Department of Commerce, and of data published from year to year by the United States Department of Agriculture, reveals the fact that the staple, and even minor, agricultural crops of this country have a marked tendency to geographic segregation. When the intensity of production of the various products is graphically illustrated on charts or maps, there is a decided tendency for the various crops to group themselves into certain more or less definite areas, the boundaries of which are often rather sharply drawn. We find also that when we group all crops together certain sections show a decided preponderance of production. The principal physical factors that influence localization of crops are topography, character of soil, distance from market, and climate. In the United States climate is the most fundamental, unalterable, and important, not only in influencing the geographic distribution of the crops grown, but also in determining the suitability of the land for agricultural purposes in general. Only about one half of the land area of the United States permits of profitable production of crops by ordinary farming methods, the other half being unsuited for this purpose principally by reason of roughness, infertile soil, or unfavorable climate. For the country as a whole, nearly 75 percent of the total land area was classified by the census of 1920 as being unimproved.1 About one fifth of the total amount, principally in the western half of the country, is too hilly or rough for cultivation, which leaves a large proportion unimproved for other causes than mere roughness. Much the greater part of this is unavailable by reason of unfavorable climatic conditions, principally insufficient moisture, although a considerable amount is used for grazing purposes, or for non-intensive agriculture by the employment of special methods, such as dry farming practices. The portion of the unimproved area located in the eastern half of the United States is comprised principally of lands under forest and cut-over, which are potentially agricultural, in so far as climate is concerned, although some of it, especially in the Appalachian Mountain section, is so rough or infertile as to be suitable only for growing 1 Forest land is at present classed as unimproved. When land is under forest management and producing crops of timber-as much of it probably will be in the not distant future-should not some other form of classification be used? ED.