OATS IN THE GREAT PLAINS AREA. 11 
RESULTS AT THE SEVERAL STATIONS. 
Accompanying the discussion of each station is a very brief descrip- 
tion of the soil, with particular reference to its depth and its water- 
holding capacity. Only such information is given as is necessary to 
understand fully the interpretation of the results. 
JUDITH BASIN FIELD STATION. 
The field station at Moccasin, Mont., in the Judith Basin, is located 
on a heavy clay soil of limestone origin. The soil is apparently very 
rich in available fertility. It is underlain at a depth of approxi- 
mately 3 feet by a limestone gravel that is closely cemented with lime 
materials. The gravel subsoil, which extends to a depth of about 30 
feet, is practically free from soil. While it is so closely cemented that 
it does not unduly drain the soil, it is not of a character that allows 
the storage of available water or the development of roots within it. 
The presence of gravel in the surface soil does not permit the taking 
of samples satisfactory for the study of soil moisture. Enough has 
been done, however, to make it certain that the supply of water that 
can be stored in this soil is limited. This shallowness of the soil and 
consequent limitation of the quantity of water that can be stored 
in it and recovered by the crop makes the crop dependent in large 
part upon the rains that fall while it is growing. 
While the oat crop is not at present the most important commercial 
crop in the Judith Basin, good yields have been obtained at this field 
station and a profit realized by all methods under trial. In 1912 the 
crop was destroyed by a local hail storm. Yields have therefore 
been calculated on the basis of five years. In the experiments in 
crop rotation and cultivation methods, 33 plats of oats have been 
grown each year. This number was increased by the addition of 
new work in 1913, but only work started in 1908 is here reported. 
As here presented, the results are arranged to study only the effect 
of cropping and cultivation in the one year preceding the growth of 
oats. No attempt is made to study rotations as units. 
Table V shows that while there may be great seasonal variations 
in yields the differences resulting from cultural conditions are gener- 
aDy small. With the exception of the comparatively high yield by 
summer tillage and the low yield on both brome-grass and alfalfa 
sods and following flax on brome-grass sod, the differences in yield 
from different preparations are too small to have meaning. 
The low yields on brome-grass and alfalfa sod and following flax 
on brome-grass sod are due to the fact that at this station sod crops 
recover after breaking to such an extent as to choke out the oats. 
The profitableness of these crops in themselves, together with the 
poor results which follow their breaking, indicates that the sod crops 
should remain down for long periods rather than enter into short 
rotations. 
