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PRINCIPLES OF AGRICULTURAL CHEMISTRY 



The earlier the soil warms up in the spring, the earlier it can be 

 planted. Some few seeds begin to germinate at the freezing 



Fig. 30. Fruit grown against a wall so that it will ripen. France, 

 point, but most seeds require a higher temperature. Haberlandt 1 

 1 Landw. Versuchs-stat., 17, p. 104. 



