14 Nebraska Experiment Station Research Bui. 15 
to farming. There may be a number of serious-and- valid ob- 
jections to the classification of certain crops in the spring 
and summer annual groups. The outline simply shows the \ 
order in which the census material was organized for this 
particular study. 
A. Cultivated crops treated as annuals. 
1. Winter annuals. (Cold tolerant but heat sensitive.) 
a. Winter wheat (supplementary data used). 
b. Rye. (The acreage of rye given in the census 
was treated as winter rather than spring. This of 
course causes error in counties growing spring rye, 
but this error is seldom sufficient to affect ma- 
terially any broad classification of farming re- 
gions.) 
2. Spring annuals, together with such summer an- 
nuals as are favored by cool weather and have a rel- 
atively short growing season. (Cold tolerant but 
heat sensitive.) 
a. Spring wheat (supplementary data used). 
b. Oats. (The acreage of oats given in the census 
was treated as spring. If the 1909 acreage of 
winter oats per county had been available, the j 
southern border of the summer-winter type of an- 
nual cropping could have been mapped more ac- 
curately. See page 18.) 
c. Barley. (The acreage of barley given in the cen- 
sus was treated as spring.) 
d. Emmer and speltz. 
e. Flax. 
f. Potatoes. 
g. Grains cut green. (This acreage could not be* 
used, as it contained both winter and spring 
grains.) 
h. Peas. (The acreage in the Northern States was 
classed here . In the Middle States, where the acre- 
age is very small, peas were omitted.) 
i. Buckwheat. 
