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Mineral Nutrition of Plants 



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Figure i. Appearance of structure rotation plots on July 20, 1949, Pauld- 

 ing, Ohio. Upper: corn, oats, two-year alfalfa rotation. Lower: continuous 

 corn. Poor drainage characteristics and poor soil structure, which have de- 

 veloped since 1936, definitely limit plant growth through poor soil aeration 

 on this plot; there has been a definite improvement in soil structure and, 

 hence, in soil productivity on the plot shown at the top. 



