Nebraska Experiment Station Research Bid. 15 
8 
limits. 
graphical scale, soil effects are often submerged by climate. 
The reverse, however, is true within any comparatively small 
area of agricultural land. Here variations in soil often have 
sufficient range to outweigh the relatively small range of 
climatic variations. 
The location of the favorable agricultural lands with ref- 
erence to the distribution of native vegetation is striking. 
The low temperature boundaries are closely marked by the 
southern limits of the northern coniferous forests while the 
low rainfall boundaries are marked by a sparse vegetation 
i 
)] 
si 
ii 
