With regard to the soil the situation is different from that of the minerals. The growing of crops removes essential chemical elements but these can be replaced. It is estimated by our experts, however, that about one-fourth of the cultivated land in the United States, chiefly in the southeast and southwest, has lost by erosion a third of its surface soil, and that from another quarter of the land a sixth or more of surface soil has been removed. These are colossal losses and they are increasing every year, yet the threat of an insufficient supply of food or fiber in the future now appears to exist no longer.

There are still nearly 300 million acres of land devoted mainly to pasture which can put into crops by ploughing and planting, and another 300 million acres which could be used for crops after clearing of the forest or after drainage or irrigation. Despite this vast reserve of land available for crop production the nation can ill afford to permit waste of soil resources by erosion and allow the people of a district to be slowly reduced to poverty. Where the land cannot be protected by terracing it would seem that it may be restored to forest or grass. Erosion, of course, leads to the silting of the rivers and to floods, which are matters of national concern. The utilization of eroding lands for forest o grazing would also tend to reduce the surplus of farm products.

The economic prospects of agriculture have been changed by the rapid decline of the birth rate, the restriction upon immigration, the great decrease in exports of farm products, and by progress in technique. There has been no increase in crop acreage for 15 years, nor in acre-yields of the crops as a whole for 30 years, yet agricultural production has increased about 50 percent since the beginning of the century. The advancing efficiency in land utilization is due principally to the increased use of power machinery in agriculture, and to the application of scientific knowledge. Use of the engine has reduced the number of horses and mules by 10 millions during the past 14 years, thereby releasing about 30 million acres of plough land and large areas of pasture for raising meat and mild animals or for growing food and fiber crops. Total mechanical power used on farms increased from 0.5 horse power per worker in 1900 to 5.6 in 1930. Improvements in animal husbandry have resulted in a further saving of probably 25 million acres of crop land since the World War.

It is estimated by our experts that agricultural output per worker increased 22 percent between the average of the decade 1912-1921 and the average of the decade 1922-1931. A farmer now provides food for himself and three members of his family, for 12 Americans not living on farms and for 2 foreigners–a total of 18 persons.

The result of these changing forces has been a volume of agricultural production in excess of market demands, and this in turn affords a partial explanation of the net loss in farm population of 1.2 million between 1920 and 1930, although a reversal of population of farmers to cities means an
abandonment of crop lands which should be first from the poorer lands, for there is a problem of the rural poverty areas as truly as there is a problem of the urban slums.

The power line is likely to supplement the automobile in drawing farmers to the highways and in causing the gradual abandonment of much land back in the hills. The selective abandonment of the poorer land is being facilitated by the agencies of communication such as the postal service, the newspaper, the telephone, and the radio.

Should government endeavor to facilitate or direct this migration from the farms in the handicapped areas, relocating on more fertile or favorably located and those who wish to continue farming? Often the economies to be obtained in the provision of schools and roads alone would justify the county or state in such actions. This might lead to the zoning of rural lands. On the other hand, should government policy aim at retaining as much as possible of the natural increase of the farm population on farms or in rural areas as a means of maintaining the national population?

Abandoned farm lands return to brush but are not likely to be used for lumber production for some time. There are, however, other uses of low grade forest lands: conserving game and fur bearing animals, affording recreation, protecting water supplies and preventing floods. The responsibility for the development of such uses and the reorganization of the school and road systems in regions consisting in substantial part of such lands seem likely to devolve largely upon the state.

The problem of export markets may be serious for a time. Technological progress in land utilization in western Europe and in Russia is proceeding as in the United States, while in northwestern Europe, where most of the exports of farm products are sent, the prospect is for a stationary or declining population within a few decades. Losses in European markets in part may be compensated for by the growth of markets in the countries bordering on the Pacific Ocean. To deal with the agricultural surplus raises the broad question of land utilization and of domestic and foreign markets.

The tendencies which have given rise to these problems of surpluses, markets and shifts in population rest in large part upon two great movements: technological advance and declining population growth. The advance of science and invention may be expected to continue. It may lead to the widespread adoption of mechanical corn harvesters and cotton pickers for the handling of two of our greatest crops, and to the wider use of other agricultural machines now in existence. If so, it will give a premium in crop production to the larger farms on the more level lands, and it will lead to reduction in the number of people engaged in commercial agriculture and to further shifts in population.

Source: Recent Social Trends in the United States, an examination of the social state of the United States at the end of the 1920s undertaken at the direction of President Herbert Hoover.