THE MOISTURE PROBLEM 



85 



row left on its edge, or the land plowed when it is too 

 dry, or allowed to bake after being plowed when too wet, 

 open air spaces 

 are created be- 

 low the furrow 

 slice which ser- 

 iously lessens 

 not only the 

 moisture move- 

 ment from the 

 subsoil to the 

 seed or to plant 

 roots but also 

 the ability of 

 the roots to 

 reach out after 

 moisture. Mois- 

 ture cannot rise 

 through large, 

 loose, open 

 spaces in the 

 bottom of the 

 furrow slice, nor 

 can plant roots 

 grow down 

 through them 

 satisfactorily. 

 Obviously, these 

 practices, unless 

 modified, are un- 

 suited to dry 



Fig. 29. A Well Tilled Field of Potatoes. 



Three stages of development in the growth of a 

 field of potatoes. Courtesy Dr. Seager Wheeler. 



farm conditions. 

 The chief means by which the moisture stored and 



