Freezing Injury or Seed Corn 
75 
This variation in time of freezing weather together with a 
great seasonal variation in time of corn maturity has a marked 
bearing in different years upon the condition of corn for seed 
when left standing in the field. 
The average dates of the first killing frost in the field in 
the fall for various parts of Nebraska are given in Figure II. 
FREEZING INJURY INEVITABLE IN OCCASIONAL YEARS 
Experience has taught that the best adapted, highest pro- 
ducing corn for any locality in Nebraska, or in the greater part 
of the Corn Belt, does not mature and dry sufficiently in all 
seasons to escape freezing injury when left exposed to low tem- 
peratures either in the field or in the crib. It would not be 
practicable in most of the Corn Belt to grow corn sufficiently 
early to escape damage from freezing every year, because such 
corn would be too small and early to give best results. The 
best adapted and most productive types appear to be those 
which utilF'> practically the entire growing season of the aver- 
age year. In the majority of years, such types should ripen 
fully before the first killing frost, altho in occasional years both 
the yield and the quality may be reduced by autumn frosts. 
Seasonal variation in the time of maturity of a given corn 
in a given locality may be illustrated by the relative maturity 
of Hogue’s Yellow Dent corn at the Experiment Station in 
1911 and 1917. This is a standard well-adapted type for con- 
ditions prevailing at the Experiment Station. In 1911 the grain 
of this corn contained only II per cent moisture on October 1, 
while it contained 38 per cent on October 1, 1917. It was well 
matured on September 6, 1911, whereas it was not so mature a 
month later in 1917. In this vicinity the normal date of ripen- 
ing for this varietv is September 20, while the mean date of the 
first killing frost is October 11. According to this, corn which 
is unsurpassed in average production at the Experiment Station 
ripens, as an average, about 3 weeks before the mean date of 
the first killing frost. 
This seasonal variation makes possible in many years the 
growing of late maturing tvpes of corn in localities where 
thev normally are not adapted. But the character of the season 
and the date of the first killing frost cannot be foretold at plant- 
ing time. Therefore, un adapted, late maturing types which do 
not reach their full development before the average date of the 
first killing frost should not be grown. They require for their 
full development the exceptional seasons in which the first 
killing frost comes very late. In too great a proportion of the 
