CHAPTER IV. 

 THE MOISTURE PROBLEM 



Water is required in large amounts by growing plants 

 and the source of all moisture for crops, except under 

 irrigation, is the clouds. The average precipitation is 

 a general guide to the amount that is likely to fall in any 

 year. Areas having more than 30 inches precipitation 

 are spoken of as humid ; those having between 20 and 30, 

 sub-humid; between 10 and 20 inches, semi-arid; while 

 those having less than 10 are called arid. Most of West- 

 ern Canada is semi-arid; our average precipitation is 

 low and the water requirements of growing crops is 

 high; the chief cause of low yields is lack of moisture. 



The moisture problem briefly stated consists of (1) 

 storing as much moisture as possible in the soil, (2) 

 conserving it as well as we can, (3) keeping it available 

 to the seed and plant roots, and (4) making the most 

 efficient use of it. 



53. Storing Moisture in the Soil.— When moisture falls 

 upon the land in the form of rain it is either absorbed 

 by the soil or it finds its way to ditches, ravines or 

 sloughs. The problem of storing moisture is one of pre- 

 venting the "run off'' which occurs chiefly at two sea- 

 sons, one during the heavy midsummer rains and the 

 other when the snow melts in the spring. The amount 



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