BREAKING THE VIRGIN PRAIRIE 127 



sary, and (3) that a mellow layer of soil be formed oil 

 the surface to function efficiently as a seed covering after 

 the passage of the drill. The use of the packer, disc and 

 harrow in the order mentioned and at the right time is 

 the best way to accomplish the desired results. Ordin- 

 arily, the land is firmed down by a packer or plankor 

 soon after plowing, disked as soon as the sod has partial- 

 ly rotted and then harrowed to prepare a uniform ana 

 lev-'H sin face. 



95. Some Desirable Practices in "Breaking" Prairie Sod. 

 Most of the practices to be discussed under this head- 

 ing might easily be inferred from what has already been 



Fig. 47. Improper Breaking for Dry Areas. 



The furrow slice instead of lying on the corner of its neighbor should 



lie flat. 



said. In discussing them it should be kept in mind that 

 a practice that is best in one district may not be good in 

 another. Each so-called "desirable" practice should 

 therefore be considered in its relation to the needs of the 

 situation, the presence of creeping-rooted plants and the 

 average rainfall being the chief determining factor. 



96. Break Early to Obtain Maximum Yields. The de- 

 crease in yield of wheat on breaking done after the 

 tenth of June at Saskatoon has been found to average one 

 bushel per acre per week. In more humid districts the 

 decrease will probably be less and in drier districts 

 greater than this figure. The following table gives the 



