The Potato Industry or Colorado. 19 
getting land ready eor potatoes. 
Preparing Raw Soils. —It is better for the grower to break raw 
lands during the summer of the year previous to growing the crop. 
This puts the soil in better condition for taking and holding water 
and for culture than where the raw soil is broken in the spring before 
planting. New land in Colorado seldom produces the maximum 
yield of potatoes, because it is deficient in vegetable matter and 
therefore in nitrogen, while the physical condition of the soil can 
never be gotten in the best shape the first year. 
The Best Crop for Subduing Raw Lands in Colorado is un¬ 
doubtedly the potato, even for soils really too heavy for this plant. 
No crop puts the land in so good condition for the succeeding crop, 
or for leveling and getting the land into alfalfa. The continuous 
cultivation of the potato crop, the irrigation, and then the digging 
in the fall (which is a far better mulch than a fall plowing), leave 
an exceedingly favorable physical and chemical condition of the soil. 
Various Rotations. —In northern Colorado the most common 
rotation is, potatoes two years, followed by grain as a nurse crop 
for alfalfa, then alfalfa as a hay crop two years—a five year rota¬ 
tion. Where diseases have interfered with the potato crop, this is 
sometimes changed to potatoes one year, grain one year, potatoes 
one year, grain and alfalfa one year, alfalfa two years, then back 
to potatoes. Where the canning of peas has become an industry, 
peas have been grown between the two potato years in the place of 
grains. On the west slope the rotation for the most part is similar 
to that in northern Colorado. Sugar beets are often used in place 
of the second year of potatoes. 
In the San Luis Valley the rotation is largely potatoes one year, 
peas one year, grain one year. 
Alfalfa, Peas or Clover used in rotation prepares the land for 
potatoes by improving its physical condition and furnishing the 
necessary nitrogen. Experiments made by Paddock and Rolfs in 
the Greeley district showed that the use of a commercial fertilizer 
the middle of the season, is largely accountable for failures to grow crops 
in these districts. These soils for the most part are not only heavy at the 
surface but are underlaid by a stratum of almost impervious clay. In 
the Greeley district even the heavy soils are for the most part underlaid 
by a gravel stratum which makes good drainage and which appears to 
prevent the packing of the soil. At almost no time in our experience in 
growing potatoes at Port Collins, has there been a season when it was 
possible to dig into the ridge where the potato plants were growing, with 
the naked hand. At Greeley it is usually not difficult to dig the potatoes 
with the naked hand even where they are from six to eight inches beneath 
the surface. This, we believe, in a great measure accounts for the differ¬ 
ences in soils as to their ability to grow potatoes. However, it is found 
that in the high altitudes and in some places of the West Slope potatoes 
are grown in soils that are apparently heavier than that of the college 
farm. 
