26 
The: Colorado Experiment Station 
listed. Experiment shows that this practice stops danger of blow¬ 
ing. In the spring, just as early as possible, the middles are 
broken out. 
Listing tends to lengthen the time required to develop corn 
to full maturity, consequently, planting corn on listed land is not 
always advisable. Where, on account of the difficulty of matur¬ 
ing listed corn, it is advisable to surface plant, the listed ground 
is worked down by disking and harrowing. 
Often on the lighter lands, experiment has shown that a sys¬ 
tem may be followed which keeps down weeds and conserves 
moisture at a great reduction of labor without reducing yields. 
Thus the cost of production is kept down. The suggested system 
is carried out as follows : Starting the system and rotation with 
summer tilled land, the first crop put on is winter wheat. Im¬ 
mediately after the binder, the land is double disked for the 
double purpose of killing all weeds which spring up and to put 
the surface in good condition to catch rainfall. The following 
spring the land is double disked early, then corn or other culti¬ 
vated crop is planted. Following corn, small grain is planted. 
The yields of grain after corn or other clean cultivated crop are 
nearly as large as after the fallow. After this last small grain 
crop is cut, the land is double disked. It is then allowed to lie. 
The following spring, as soon as weeds start, the soil is again 
disked to kill weeds, preserve tilth and the better to catch rain¬ 
fall. In June and July the land is plowed thoroly and deeply, 
disked and harrowed immediately behind the plow. Winter wheat 
is planted in September and the rotation is under way again. Such 
management has been found more successful on many soils than 
more frequent plowing and the cost of following the system is 
very low. 
Upon the soils which give better results from plowing each 
season, the soil should preferably be plowed early in the fall, the 
earlier the better. 
Time for Planting .—Over most of the plains area, corn can 
be planted by the 10th of May. In the extreme southeastern part 
of the Colorado plains, planting can be done the last of April 
or the first of May. In the extreme eastern part, some planting 
may be done by the first of May, but usually it is not wise to put 
in corn very much before May 10th. Nearly always the plains 
are subjected to a frost about the middle of May and there is 
little use of getting corn in prior to this danger period for frosts. 
By this time the ground has become somewhat warmed so that the 
crop will start off readily. 
