UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 253 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief SEW^fU 
Washington, D. C. T Jime 29 > 1915 - 
THE EFFECT OF DIFFERENT TIMES OF PLOWING 
SMALL-GRAIN STUBBLE IN EASTERN COLORADO. 
By 0. J. Grace, 
Assistant, Dry-Land Agriculture Investigations. 
INTRODUCTION. 
The data here presented have been obtained during the past six 
years at the Akron (Colo.) Field Station of the Bureau of Plant 
Industry. Though these data are from the Akron station only, they 
agree in the main with those obtained from other stations, and it is 
believed that the principles deduced are of general application in 
the Great Plains. 
The time of plowing is one of the most frequently discussed sub- 
jects and one on which very few authoritative figures can be ob- 
tained. This is not due so much to a limited amount of experi- 
mental work as to the seemingly contradictory results obtained. In 
the following pages the major portion of the discussion will be con- 
fined to the time of plowing for spring wheat, which, although a crop 
of secondary importance in this region, was selected because a series 
of moisture determinations has been made in connection with its 
growth. Oats and corn have given similar results, so that wheat 
may be taken as representative of the spring crops. 
The object of presenting these data at this time is not to advocate 
either spring or fall plowing, but to show, if possible, correlations 
between precipitation and time of plowing. Six years' records, with 
yields no more consistent than those here presented, are not suffi- 
cient justification for forming conclusions and laying down hard 
and fast rules in agriculture. In a climate where the precipitation 
is as erratic as it is in eastern Colorado there are very few farming 
operations which can be done successfully by rule of thumb, and 
this is especially true of any rule for time, depth, and method of 
plowing. 
By many who have had little or no experience in actual farming 
in the semiarid regions of the West annual plowing is considered as 
93352— Bull. 253—15 
