There has never been much enthusiasm for the humid tropic lowlands as the seedbed of agriculture. Of late years the students of botany have turned to the temperate forest area and particularly to the mountain valley as the seat of agriculture. This has been championed by N. I. Vavilov and a group of Russian scientists, sent to the Americas in the 1920’s, who made a most elaborate study of our native cultivated plants. Much of their evidence is too technical for presentation here, but their conclusions have seemed convincing to many students.[7] A mountain valley provides a wider range of temperature and rainfall and a greater variety of native plants. Its forest trees, before they are cleared by girdling and burning, store up a rich humus under their shade. Costa Rica and El Salvador—full of isolated mountain valleys—contain, according to Henry J. Bruman, as many species of plants as the United States, in spite of the fact that the United States is a hundred times the size of the two countries together.[8] The Russians believe that agriculture took early shape in certain mountain valley areas, including southern Mexico, Central America, Colombia, highland Peru, western Bolivia, and southern Chile. Though they do not commit themselves as to whether agriculture originated in one place and spread later to others, “their evidence,” Sauer thinks, “may be interpreted in favor of multiple independent beginnings.”[9] But Bruman, writing of their work, points out that the “enormous spread of maize and beans, of cotton and tobacco, for example, shows that there is ‘something of the undivided whole’ in the great cultures of the New World, as Vavilov well expresses it.”[10] Richard S. MacNeish, an archaeologist who spent at least a dozen years on the matter, declared in 1960, “There were multiple origins of New World domesticated plants, at different times.”[11]
It is amusing to note that the diffusionists and the partisans of independent invention change places on the subject of corn. Spinden diffuses all corn from Middle America. Gladwin plumps for various areas of independent invention, including the Mississippi Valley.[12]
The Indian’s Accomplishment in Agriculture
There can be no argument over the remarkable nature of certain things that the Indian farmer accomplished. Through long cultivation he produced the seedless pineapple. When he found that one form of manioc was poisonous, he took thought and devised a press for squeezing out the deadly cyanide while retaining the starch. Bruman calls this “one of the outstanding accomplishments of the American Indian.”[13] He says further: