[JAMES] AN HISTORICAL WAR CROP 115 
the number of heads per plant was increased most where the con- 
ditions after seeding were favorable to abundant tillering, that the 
grains per head were increased more than either of the other two 
under conditions where, for some cause or other, tillering was .hin- 
dered and fertilization of blossoms favored and, that the weight per 
grain was increased most where the conditions both at tillering and 
at blossoming were not ideal. In other words, at such time as the 
soil and climatic factors were favorable the plants made vigorous 
growth and this was evidenced in greater tillering, seed formation 
and better filling. : 
“If we were asked to venture an opinion as to the contribution 
of each of these factors to the 50 to 60 per cent average increase in 
yield in the 1915 crop over the 1914 one when sown under similar 
cultural conditions in our Investigation Field here, we should say 
20% of it was expressed in greater tillering, 20% in more seeds per 
head and 15% in the size or weight of the kernels. Of course, the 
total increase was much greater in some other places than at Sas- 
katoon, and no doubt the expression of the increase would be different 
also. 
‘Whether the evidence of the large yield is to be found in more 
heads per plant or more grains per head or heavier grains or in all 
of these, we are satisfied that the causes of the increase in any or all 
are to be attributed to several different factors among which are: 
“(1) The heavy precipitation in the fall of 1914 which came too 
late to be seriously affected by evaporation and which encouraged fall 
tillage under soil conditions that were very much more favorable 
than in any other year in my experience. 
““(2) The favorable seeding conditions in the spring of 1915. 
“(3) The cool growing season until August. This fostered til- 
lering and did not lessen fertilization of blossoms as does hot dry 
weather. 
(4) The later than usual summer rains which filled the grain 
better than our normal dry ripening seasons do. 
“(5) The later date of the first fall frost in 1915 which permitted 
full maturity in nearly all districts. 
“Other influencing factors no doubt were, (1) the extra tillage 
given in those areas where the crop was a partial failure in 1914 
and in all parts where the 1914 crop was harvested early, and (2) the 
greater store of soluble or available plant food in the soil in the spring 
of 1915, as a result of the combination of the long autumn season of 
1914, the small draft upon the soil by that year’s crop and the ab- 
normal fall rains preceding the 1915 crop. 
