244 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1949 
The situation is different when the forest is removed from a leached 
soil in the humid region. The organic matter and nutrients must be 
built up far above the levels present in the natural soils, and the bal- 
ance is delicate, both the natural balance and the one created by man. 
Too much lime added, and other nutrients become unavailable. Too 
much nitrogen added, and plants are weak, poor in quality, and easy 
prey to diseases. Water control without proper fertility may be 
impractical and wasteful. Rarely can the maximum economic pro- 
duction from soils in humid forested regions be realized by application 
of just one or two scientific practices. 
CONCLUSIONS 
In the past, the environment determined man’s development and set 
definite limits on his activities. His music and architecture, his 
economic and political institutions, in fact, his whole social being 
was strongly influenced by the potentialities of the soil. As modern 
soil science develops further, the environment will determine less 
what man is and more what he does. Scientists will learn more 
precisely how to carry specific management practices from one soil to 
another, in order to achieve good productivity. 
As science progresses there will be increasing emphasis upon sym- 
metry in science, upon fitting the parts together. Although such an 
emphasis runs counter to the modern trend of specialization, organiza- 
tional devices both in research and education will be created so that 
teams of scientists of different specialties work together. Only in 
this way can even a small part of our agricultural potentialities be 
realized or more than a small part of our soil science be put to work. 
Even now, there would be enough food if soil science were used to the 
fullest extent. There are no apparent limits to our potentiality; it is 
far away, far beyond our present production. Even in this great 
country there is needless inefficiency in agriculture, needless from the 
standpoint of proved scientific principles and practices. Some farm- 
ers do not know what to do; others have no way of knowing, or of 
following the practices if they did know. Thus even on the soil 
already occupied, the opportunities for more food are enormous. In 
addition, there are still areas in the interior of continents that are 
only partly used for lack of industry or transportation. This is 
especially true concerning Asia. 
Even more important than these wasted opportunities are the great 
areas of tropical soils. Some say that the resources of the Tropics are 
almost without limit; others say they are nil. The truth is that with- 
out modern science their productivity is small; thus it might be said 
that the Tropics are overpopulated now. However, with the applica- 
tion of a symmetrical soil science, the potentialities of the Tropics are 
