some localities where the normal average is only about ten inches. Similarly low 

 annual rainfall characterizes a large part of the Canadian acreage and the south- 

 ern areas of the Argentine and parts of Russia. 



Where annual rainfall is low, the seasonal distribution through the wheat 

 growing season is often a factor, as in the plains region of the United States. 



A somewhat dry climate is favorable for hard, dark wheats, the wheats of 

 the more humid areas having a tendency to soft and starchy composition. The 

 ideal climate for wheat is one characterized by a wet winter, a cool and rather 

 juoist spring with a warm summer becoming drier as it becomes warmer. Wheat 

 requires only light rains after blossoming time and rather dry air toward har- 

 vest, but without hot, scorching winds. 



Montana's grain belt lies largely within the range of ten to twenty inches of 

 annual rainfall, with such important producing areas as the Judith Basin and 

 Gallatin, as well as other mountain valleys, ranging well above this average. 

 Very small and scattered areas of the state fall below ten inches. A character- 

 istic of Montana annual precipitation east of the Continental Divide is that sixty 

 to seventy per cent falls between April 1st and September 30th, with the seventy 

 per cent including most of the eastern half of the state. (See map on following 

 page). 



Montana's winter wheat acreage is densest in central and south central Mon- 

 tana and tends to coincide with the areas of largest annual rainfall. In a general 

 way the higher annual precipitation records mean more fall moisture and a 

 heavier winter snowfall, both of which conditions are necessary for fall growth 

 and winter protection of winter wheat. Moreover the westward location of winter 

 wheat toward the mountains brings the crop within a more equable zone of winter 

 temperature. 



Spring wheat, however, is the large bulk of Montana's wheat production. 

 The heavy producing area lies generally east of the main winter wheat acreage 

 and largely in the eastern half of the state, where the annual rainfall ranges 

 between ten and twenty inches and an average of sixty to seventy per cent of this 

 amount comes within the growing season of the year. 



DISTRIBUTION OF MONTANA SPRING WHEAT ACREAGE 



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