LUTHER BURBANK 



shown in the results obtained even with wheat on 

 fields drained and those not drained. Only one or 

 two ditches across a field have made it possible to 

 produce two or three times as large a crop as was 

 grown in the same field before the ditches were 

 made. 



In a certain oat field in Wisconsin, the yield per 

 acre was doubled by drainage. The yield before 

 drainage was only sixteen bushels, but after drain- 

 age it increased to 32.3 bushels per acre. 



There are at least two bad effects to be expected 

 from an oversupply of water. They are : 



(1) An oversupply makes certain areas so soft 

 that they cannot be cultivated at all or at least not 

 until late in the spring. 



(2) Air, which is essential to plant growth, 

 cannot enter the soil supplied with a superabund- 

 ance of water. 



Air is as necessary to the roots of plants as 

 water and it is upon this principle that all systems 

 of cultivation and drainage are based. 



The complicated chemical changes in the 

 growth of the plant cannot take place unless there 

 is sufficient of both air and water. Roots cannot 

 exist where there is a superabundance of water 

 in the soil. 



There are several systems of drainage which 

 will not be discussed here. I consider underdrain- 



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