EFFECT OF ALFALFA ON YIELDS OF FIELD CHOPS. 6 
In the above list of the seven rotations which include alfalfa, 
that crop was followed by potatoes in four cases and by oats, wheat, 
and corn in the other three. The second-year effect of alfalfa is 
shown in two cases on sugar beets and in five cases on oats. In 
the three 6-year rotations, sugar beets are grown the third year fol- 
lowing the alfalfa and presumably, therefore, derive the least benefit 
from that crop. 
The cultural operations used with these rotations have been only 
those demanded by good farming. With respect to any one crop, 
the same variety has been used in all rotations at each station each 
year. The same varieties have not been used at the different stations, 
nor has the same variety been used for all years at the same station. 
It has been the aim to use one of the best of the locally adapted 
varieties in each case. 
In the rotations where alfalfa follows sugar beets, the alfalfa has 
been seeded in the spring following the beet crop, and consequently 
it has done little more than get well established the first year. Where 
the alfalfa follows oats it has been customary to seed it in the fall 
in the oat stubble, and in general this has resulted in a good stand 
and nearly a full crop the following season. At the close of the alfalfa 
period in these rotations the alfalfa sod has been plowed immediately 
after the last cutting. This first plowing or " crowning," as it is 
called, is done only 3 or 4 inches deep, in order to cut the roots 
close to the surface and kill the plants. After the inverted sod has 
dried out well it is disked, and the land is then plowed to a depth of 
8 or 9 inches. 
The field work of these rotation experiments has been under the 
direction of the farm superintendent at each station and under the 
immediate supervision of a scientific assistant, who is charged with 
performing or directing the cultural operations, the irrigation, and 
the harvesting, and with taking the field notes and reporting the 
results each year. 1 
RESULTS OF THE EXPERIMENTS. 
IRISH POTATOES. 
There are four pairs of rotations at each station in which the mem- 
bers of the pairs differ from each other only in that one includes a 
period of alfalfa and the other does not. In two of these cases, 
1 The following is the personnel concerned with the field work of these rotation experiments: At Scotts- 
bluff,Mr. Fritz Knorr was superintendent from 1910 to the end of 1916. Mr. James A. Holden was in charge 
of the irrigated rotations from the spring of 1912 until the end of 1916, when he succeeded Mr. Knorr as 
farm superintendent. Mr. David W. Jones supervised the irrigated rotation work during 1917 and the 
early part of 1918, when he entered the military service; during the remainder of the season Mr. Holden 
directed the work. At Belle Fourche, Mr. Beyer Aune has been superintendent since 1909. He has kept 
in close touch with the irrigated rotation work, being assisted at different times by Mr. John B. Wentz, 
Mr. N. L. Mattice, Mr. George T. RatlifTe, and Mr. Oscar R. Mathews. At Huntley Mr. Dan Hansen 
has been superintendent since 1910. The irrigated rotations were under the supervision of Mr. John M. 
Spain during 1912, Mr. John W. Knorr during 1914, and Mr. Edward G. Noble from 1915 until the summer of 
1918, when Mr. Noble entered the military service. Mr. Hansen directed the work in 1913 and during the 
latter part of 1918. 
