NORTHERN GREAT PLAINS FIELD STATION, 1913-1922 59 
the lighter rate of seeding has been entirely satisfactory, but under 
ordinary conditions 7 or 8 pounds per acre seems to be better. This 
should be sown with a grain drill from the grass-seeder attachment, 
and without a nurse crop. Alfalfa has been sown fairly early at the 
station, or soon after wheat seeding. Early seeding is desirable on 
clean ground, but if the ground is likely to become weedy seeding 
should be delayed and the land cultivated to kill the weeds. : 
Different nurse crops, such as wheat, oats, barley, and flax, have 
been sown with alfalfa. During the period of dry seasons the stands 
with nurse crops were not satisfactory. In order to insure a stand, 
alfalfa should be sown alone, as the chances are against obtaining a 
‘stand with any nurse crop. Alfalfa is too valuable a crop not to give 
it the best possible chance for success. 
The seedings of alfalfa at the station in 1920 were a failure. This 
was because of the dry season and weeds. In 1921 a satisfactory 
stand of alfalfa was obtained, but was lost by winterkilling. The 
weeds, especially Russian thistles, came up very thick. They were 
not cut during the season. This is usually the best plan to follow, 
and a good rule to keep in mind is “‘ to sow alfalfa alone and leave it 
alone during the first season.”” If weeds grow thick during the season, 
they should be burned if possible early in the spring of the next season, 
or raked into bunches and hauled off the field. 
The average yield of alfalfa hay for the 4-year period 1916-1919 
was approximately 24% tons per acre, which is higher than the yield 
of any other forage crop shown in Table 21. Alfalfa produced a 
greater tonnage in four seasons than either brome grass or the wheat 
grasses did in seven. 
Many varieties of alfalfa have been tried out for varying periods. 
Some varieties winterkill even in mild winters. Some varieties have 
winterkilled to the extent of more than 50 per cent during a winter 
when Grimm alfalfa showed no winterkilling. The details of the 
results with the different varieties can not be included in this report. 
Sweet clover has been under trial since the station was started. 
The results obtained have not been entirely satisfactory, as it has not 
always been possible to get a stand because of drought and weeds, and 
sometimes it winterkills. The ordinary white sweet clover ( Melilotus 
alba) has winterkilled to some extent during most of the winters. 
Yellow sweet clover (MV. officinalis) was first sown in 1918. It does 
not winterkill as much as white sweet clover. In two different four- 
year rotations sweetclover has been seeded on disked corn ground 
with wheat and oats as nurse crops in the rotation and the tillage 
methods of the Office of Dry-Land Agriculture Investigations. In 
these rotations the sweetclover is turned under for green manure. 
There was a growth to turn under each year from 1915 to 1922, inclu- 
Slve, except in 1921 and 1922 because of drought and winterkilling. 
Ordinary white sweet clover was used in these rotations. 
Sweetclover when cut for hay normally lives but two seasons. 
Therefore, for continuous hay production, it must be seeded every 
year. In this region it usually produces only a light crop or no crop 
at all the season itissown. Since sweet clover normally lives but two 
seasons, it is usually sown with a nurse crop of wheat, oats, or flax. 
A better stand is generally obtained under dry-land conditions when 
it is sown alone at the rate of 10 to 15 pounds per acre, but this requires 
the use of the land for two years for one crop of hay, and a stand Is 
