Certain Spatial Aspects of American Soybean Culture

CERTAIN SPATIAL ASPECTS OF AMERICAN SOYBEAN CULTURE L . A rnold Siniard* Many changes in agricultural land use in the United States have occurred during the past half century. None has been as impressive as the increase in soybean acreage. From a total planting of only 450,000 acres in 1925, farmers have increased their plantings year-by-year and decade-by-decade to the 42.8 million acres planted in 1971. Soybeans differ from many other crops grown in the United States in that market demand, both foreign and domestic, has continued to grow rapidly while the production per acre has not increased as dramatically as it has in the case of com, cotton, and rice. Thus, acreage of these latter crops has either declined or increased relatively little while soybean acreage has doubled during each of the two decades between 1950 and 1970. Munn discussed the production and utilization of soybeans in the United States in a paper published in 1950. (1) In the same year a paper by Prunty examined the importance of soybeans in the lower Mississippi Valley. (2) This paper continues the investigation of the rise of the soybean in the United States to its position in 1969 as the third most important agricultural crop in value, after com and hay, and the fourth most important in acreage, after hay, corn, and wheat. The changes in acreage distribution over the twenty year period since the work of Munn and Prunty, 1949 to 1969, can be seen by comparing Figures 1 and 2. SOURCE AND HISTORY. The exact place of origin of the soybean as a cultivated crop is lost in prehistory but it is believed to have been in eastern Asia, possibly China. (3) Its introduction to Japan via Korea probably occurred as early as 200 B.C. (4) The first description of soy­ beans in Western literature is found in the writings of Englebert Kaempfer in 1712, and the first account of soybeans being grown in the United States was published in 1804. (5) The first commercial production of soybean oil and meal from domestically grown seed occurred in North Carolina in 1915. (6) Despite the early introduction, only about 450,000 acres of soybeans were harvested in 1925. Some three fourths of the total acreage was harvested for hay or plowed under as a “green manure” crop. Since then, acreage and production have doubled again and again. The cur­ rent emphasis is on harvested beans for cash sale. Hay and “green • Mr. Siniard is instructor of geography at Memphis State University. This paper was accepted for publication in March 1972. 2 So u t h e a s t e r n G e o g r a p h e r manure” are no longer significant uses. An importer of soybeans during the early part of the century, in 1969 the United States produced over 75 percent of the world output. In that year soybeans brought in more export dollar earnings than any other agricultural crop and the United States was the only major exporter. (7) Farm value of the entire crop rose from 700 million dollars in 1950, to almost 2.6 billion dollars in 1969. (8) ENVIRONMENTAL FACTORS. Soybeans grow well on a wide variety of soils. They are better adapted than cotton or com to heavy clay soils, those which have a claypan (planosols), and the presence of a high water table. Ideally, soils should have a pH value of 6.0 to 6.5 and be supplied either naturally or artificially with a full range of mineral nutrients. (9) Major nutrients most likely to be deficient are phosphorous and potassium. If the plants are innoculated with nodulating bacteria they will take most of their nitrogen requirement from the atmosphere. V ol. XIII, No. 1 3 It has been estimated that between 20 and 30 inches of precipita­ tion are required for a soybean crop. (10) Comparison of a map of ayerage annual precipitation with Figure 2 indicates that there is very little soybean acreage in areas receiving less than 30 inches, and the exceptional areas usually are irrigated. The soybean plant is rather drought resistant during its early growth...