128 



WHEAT CULTURE 



Winter-killing. Winter-killing is a source of large loss to the 

 wheat growers. The United States Department of Agriculture re- 

 ports every year the acreage abandoned due to winter-killing. The 

 percentage abandoned for 11 years is shown as follows : 



Percentage 



Year 

 1901 

 1902 

 1903 

 1904 

 1905 

 1906 



15.2 

 2.8 



15.4 

 4.6 

 5.5 



Year 

 1907 

 1908 

 1909 

 1910 

 1911 



Average 



Percentage 

 .. 11.2 

 .. 4.2 



.. 7.2 



.. 13.3 



9.0 



10.5 



Pia. 50. Drilling wheat with a double-disk drill. 



Winter-killing is due to several causes : ( 1 ) Heaving out by freez- 

 ing of soil. All heavy soils in humid regions heave, due to alternate 

 freezing and thawing. This breaks the wheat roots and throws the 

 plants out on the surface. (2) Winter drying. In the Great Plains 

 region the soil is often dry all winter with no snow covering. Large 

 cracks develop and the plants are slowly dried out, especially on 

 loose or poorly prepared soil. (3) Late sowing on poor soil, when 

 the plants are so weak they kill by direct freezing. 



Seed Wheat. While every grower should always be on the 

 lookout for new or improved varieties, he should, in the main, grow 

 the variety that long experience has shown to be best for his region, 

 and try the new varieties only experimentally. 



