CROP PRODUCTION IN THE GREAT PLAINS AREA. 25 
method of destroying the weeds and thus saving the moisture that 
would be used by them if allowed to grow. The same object may be 
accomplished by disking soon after the weeds have started. This 
method has the advantage of being more rapid than plowing, thus 
making it possible to cover more ground with the same number of 
teams and men. But as the land will have to be plowed before 
another crop is sown, the labor of disking is mostly lost, although the 
labor of plowing the disked land may be somewhat less than if it 
were not disked and a better job of plowing may sometimes be done 
on the disked land. The cost of early fall plowing or disking, when 
the weather is hot and the men and teams are needed for stacking, 
thrashing, and hauling grain, is greater than later in the fall, when 
the weather is cooler and there is less other work for men and teams. 
All of these facts should be taken into consideration before going 
to the extra expense of tillage to kill weeds immediately after harvest. 
Spring plowing or disking, as soon as the weed seeds have ger- 
minated, is usually a profitable practice. Where small grain is to be 
sown, the sowing should be done soon after plowing; but where corn, 
potatoes, or the sorghums are to be grown there is often a period of 
several weeks between the time of the germination of the weed seeds 
and the time when the season is sufficiently advanced to plant the 
crop. This period should be utilized as far as possible for the destruc- 
tion of weeds before the crop is planted. Much labor in keeping the 
crop free from weeds during its growing period can thus be saved. 
Harrowing small grain for the destruction of weeds after the grain 
is sown and until it has reached a height of 3 or 4 inches may some- 
times be practiced to advantage. Experimental evidence does not 
show it to be generally profitable. Harrowing corn and potatoes 
after planting and until the young plants have attained a height of 
2 or 3 inches is quite generally practiced to advantage. 
It is absolutely essential for the most profitable growth of corn, 
potatoes, the sorghums, and, in fact, all the intertilled crops, that 
sufficient tillage be given to keep the growing crop free from weeds 
until the plants have attained such growth that they will be seriously 
injured by the cultivators or the horses. 
IMPROVING THE PHYSICAL CONDITION OF THE SOIL. 
As has been already shown, accessory tillage for the destruction 
of weeds usually will accomplish all that can be accomplished by 
tillage in keeping the soil in proper physical condition during the 
intervals between plowings. There is, however, one exception, 
namely, the accessory tillage immediately preceding the seeding of 
the crop for the purpose of preparing a suitable seed bed. The 
small-grain crops require a mellow surface and a firm condition of the 
soil below. In order to bring about this condition it is generally 
