EXPERIMENTS WITH FLAX OK" BREAKING. 5 
West of the Missouri River this soil formation grades imperceptibly 
into the residual Morton loams of southwestern Xorth Dakota and 
constitutes a transition type from the glacial soils of the eastern to 
the nonglacial or residual soils of the southwestern portion of the 
State. The Fargo loam series comprises glacial clays deposited in 
the old glacial Lake Agassiz, known more commonly as the Red 
River valley. 
The soil of the station farm is of glacial origin. The table-land 
upon which most of the agronomic work is conducted and where the 
three years' experiments with flax were made is a post-glacial terrace 
with a uniformly level surface. The surface soil is a sandy black 
loam with a subsoil of medium heavy yellow clay, fine sand, and 
gravel. 
NATIVE VEGETATION. 
The native vegetation of this region has been carefully studied by 
Mr. J. T. Sarvis. A brief quotation from one of his recent papers 
admirably sums up his conclusions as follows: x 
From actual determinations in the field the percentages of short-grass and long- 
grass cover have been found to be nearly equal, so that the formation could be put in 
either class, according to the viewpoint of the observer.. If the secondary plant layer 
is considered as the determining factor, the region falls in the long-grass formation. 
The vegetation in this particular area might be considered as in a transition zone, 
since the dominating species are typical of both formations. 
The dominating species are Bouteloua gracilis (B. oligostachya) and Stipa comata, 
* * * which is a typical long-grass species. This association is dominated by the 
Bouteloua. Sarvis [1916] has described in a paper other sections of western North 
Dakota which show the same dominating species. 
CLIMATE. 
Climatic observations were begun at Mandan with the establish- 
ment of the station in 1913. In addition to these, however, 40 years' 
continuous records of the Weather Bureau at Bismarck, 5 miles east 
of Mandan, are available. In the following paragraph Mr. Sarvis 2 
has briefly summarized these data in such a way as to show clearly 
the general climatic conditions found in this section: 
Forty years' continuous records of the Weather Bureau at Bismarck are available 
for study. Observations were begun at the Mandan station during 1913. From 1875 
to 1914, inclusive, or 40 years, the mean annual precipitation was 17. 41 inches. From 
1875 to 1908, or 34 years, the average hourly wind velocity was 10 miles; the mean 
temperature 40°, maximum 106°, minimum —44° F.; the prevailing wind direction 
for each month in the year was northwest. The average date of the last killing frost 
in spring was May 11, the first in autumn September 17, the earliest in fall August 23, 
the latest in spring June 7, for the 34-year period. The records since do not materially 
change these figures. 
1 Sarvis, J. T. Composition and density of the native vegetation in the vicinity of the Northern Great 
Plains Field Station. In Jour. Agr. Research, v. 19, no. 2, p. 63-72. 1920. 
2 Sarvis, J. T. Unpublished annual report of the agronomic experiments at Mandan, 1917. Copies on 
file in the Office of Dry-Land Agriculture, United States Department of Agriculture, Washington, D. C, 
at the Northern Great Plains Field Station, and at the North Dakota Agricultural Experiment Station, 
Agricultural College, N. Dak. 
