CORN IN THE GREAT PLAINS AREA. 9 
plants is increased until in some cases it is as much as 24 inches. It 
seems possible that this distance should be made still greater at 
some of the stations. 
SEED-BED PREPARATION. 1 
The results from different methods have been tabulated and are 
here presented in such a manner as to show the effect of the crop- 
ping or cultivation and preparation of the land in the one year 
prior to the corn planting. The tables show the effect of plowing 
for corn both in the spring and in the fall and after both corn and 
small grain, the effects of listing and of subsoiling where these have 
been tried, and the effect of summer tillage. 
In the tables as presented, the yields reported in the columns 
headed " Spring plowed, after corn' 7 are from plat A, continuously 
cropped to corn. This plat is shallow spring plowed and is given a 
minimum of cultivation. 
The yields reported in the columns headed "Fall plowed, after 
corn" are from plats continuously cropped to corn under a system 
of fall plowing and cultivation for the conservation of water both in 
the fall and in the spring. Fall plowing is done as early as prac- 
ticable. It is done to a good depth, the standard being set at 8 
inches. The ground after plowing may be worked down or left 
rough through the winter, as seems advisable. This plat at each 
station is generally known in this work as continuous-corn plat B. 
The yields reported after summer tillage are from two plats alter- 
nately summer tilled and cropped to corn. One of the pair is in 
corn and the other is summer tilled each year. These are the plats 
generally known as C and D in the continuous-corn series. Summer 
tillage is of the intensive type. The land lies fallow one year and 
until planting time the following year. In so far as it is practicable 
to do so the plat is kept free from weeds and a mulch is maintained 
on it during the period between the time of harvesting the preceding 
crop and the time of planting the corn. This period in some cases is 
as long as 18 months. In some cases it is necessary to plow the land 
more than once during this period, either to maintain a surface 
receptive to water and that will resist blowing or to prevent the 
growth of weeds. The long period of summer tillage, involving the 
nonproduction of a crop for one year, together with the intensive 
methods practiced, have made this an expensive system of treatment. 
The subsoiled plat is continuously cropped to corn. It is handled 
the same as plat B except that at the time of plowing it is subsoiled. 
A depth of about 14 inches is usually reached. Where the history of 
the station is sufficiently long for it to have been accomplished, it 
has been subsoiled two years in succession. Subsoiling was then 
suspended for two years and then resumed. The plat is known as 
E in the continuous-corn series. 
87563°— Bull. 219—15 2 
