UNITED STATES DEPARTMENT OF AGRICULTURE 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOS, Chief 



j\J$- b< &^°l; 



Washington, D. C. 



June 29, 1915. 





THE EFFECT OF DIFFERENT TIMES OF PLOWING 

 SMALL-GRAIN STURBLE 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 tho precipitation 

 (ir.'tic as it is in eastern Colorado there are very few farming 

 operations which can be, done successfully by rulo of thumb, and 

 this is especially true of any rule for time, depth, and method of 

 plowing. 



By many who have bad little or no experience in actual farming 

 in the 3emiarid regions of the West annual plowing is considered aa 



a Boll. 263— 16 



