_—s 
NORTHERN GREAT PLAINS FIELD STATION, 1913-1922 49 
Summer-fallowed plats to be seeded to small grain are usually har- 
rowed twice before seeding. Sometimes the spring-tooth harrow or 
the disk harrow is used instead of the spike-tooth harrow. The 
disk harrow is not used extensively, since it increases the work 
necessary to prepare a seed bed. It also pulverizes the soil to such 
an extent that blowing is likely to occur on the lighter soils. 
In the treatment of summer fallow the practice is to harrow the 
plats once immediately or soon after plowing. This operation levels 
the soil and leaves it in such condition that the implements used later 
do their work to the best advantage. The fallow plats have not 
been disked since 1917, or after the soil was free from sod. <A knife 
weeder and spring-tooth harrow have been used to Keep the plats 
free from weeds. In 1922 a duck-foot cultivator was used to ad- 
vantage. Fallow should be cultivated to keep it free from weeds and 
to leave it in a receptive condition for rains, and rough to avoid soil 
blowing. Figure 6 shows summer fallow after cultivation with a 
duck-foot cultivator. 
Fic. 6.—Summer-fallow plats after cultivation with a duck-foot cultivator at the Northern Great 
Plains Field Station, July 14, 1922 
In the main field spring wheat, winter wheat, barley, oats, flax, 
and corn are grown under systems of continuous cropping. Six 
plats are required for each crop. On two of the six plats crops and 
summer fallow alternate. In the south field spring wheat, barley, 
oats, and corn are grown in duplicate under the system of continuous 
cropping. Rotations 5 and 8, in the south field, are also in duplicate. 
Plat A of the continuous-cropping plats of spring-sown crops 1s 
shallow spring plowed and harrowed once before seeding; plat B is 
fall plowed to a depth of 6 inches, left rough over winter, and harrowed 
twice before seeding; plats C and D are ‘alternately summer fallowed 
and cropped, one being in crop each year; plat E is fall plowed and 
subsoiled, left rough over winter, and harrowed twice before seeding; 
and plat F is listed in the fall and worked down before seeding, except 
for corn, for which it is spring listed. 
