551 SOILS: PBOPEBTIES AND MANAGEMENT 















60 











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GRAMS 





P£G POT 



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Fig. 62. — ^Curve showing the increased growth of oats under the in- 

 fluence of constantly increasing amounts of phosphorus, that ele- 

 ment being m the minimum. 



The formula as proposed by Mitscherlich has been 

 questioned by several investigators/ who have shown 

 that a number of conditions, such as light, heat, and 



iPfeiffer, Th., Blanck, E,, andMugel, M. Wasser und Lieht 

 als Vegetationsfaktoren und ihre Beziehimgen zum Gesetze vom 

 Mimmum. Landw. Ver. Stat., Band 76, Seite 211-223. 1912. 



Also, Maz^, P. Reeherehes sur les Relations de la Plante 



