4 
Colorado Experiment Station 
to violent winds. A considerable knowledge of the climatic features 
to be met is essential because it has a strong bearing upon the cropping 
possibilities of the region. 
The altitude of this region is high, varying from 'a minimum' of 
about 3,500 feet to over 10,000 feet. These altitudes are associated 
with short seasons and cool nights. 
SOILS 
For the most part, the soils are exceedingly rich and deep. There 
are, hov/ever, localities in which the surface soils are underlaid close 
to the surface with the country rock. This country rock is quite vari¬ 
able in its exposure—different geological formations are exposed in 
differrnt localities. For the most part the soils are rather light in na¬ 
ture, running from sandy loams to as coarse as gravelly loams, sandy 
and silt loams predominating. There are an extremely small numb''r of 
places where heavy clay and adobes prevail. The acreage, compared 
to the 22,000,000 acres of plains lying in Colorado is relatively small. 
In the eastern and northeastern portion there are som'-e areas of 
almost pure sands. These have been blown about by the winds to 
form sand dunes or sand hills. Sand dunes appear at other points in 
the Colorado Plauis, but in less extensive areas. 
In some sections the soils are almost pure silt, making loams of 
great depth, more available water relations, and amount of rainfall 
considered, unusual certainty of productivity. 
The U. S. Bureau of Soils has made surveys of soil types in Lari¬ 
mer and Weld counties, and in the Arkansas ValLy. These surveys 
and a careful checking of the same territory by later workers, show 
that the prevailing types in those different sections are largfly sand> 
loams and silt loams. Those soils whTh have the proper physical 
texture and great depth are the ones which are capable of supporting 
a dry farming population. No matter how favorable the texture ma)) 
be, if the surface soil is underlaid at a short depth with impervious 
clay layers, or with on'^ or another of various beds of countrv rock, 
or with gravel, it is unfit for drv farming purposes except in the very 
wettest years, because such shallow soil is not capable of supporting 
vegetative growth thru prolonged periods of drouth. 
In the sand hill regions the tendency to blow in the prevailing high 
spring and fall winds is so great that except in wet valleys, the soil 
should not be broken up. An effort should be made to make use of 
the native pastures and to increase their carrying capacitv by intelli¬ 
gent grazing methods, by seeding in such c^'ops as Sweet Clover which 
seems to thrive under such conditions. Fv^n the sandy loams and 
silt loams if plowed up so as to dry out, and if finelv pulverized at the 
surface, will blow in a very short time after being brok^'n up—^that is, 
as soon as the organic matter contained in the fresh sod is reduced in 
amount. It is essential, therefor, on all lands to carry on some system 
of farming which will assist in keening up the organic matter content; 
to resort to such a system of plowing and cultivation as will leave the 
immediate surface more or less rough and quite coarsely granulated. 
