2 4 6 



PRINCIPLES OF AGRICULTURAL CHEMISTRY 



variations are liable to occur, and this fact must be allowed for in 

 all consideration of the data. 



Pot Experiments. In pot experiments, 1 plants are grown in 

 the soil to be tested, various additions being made to the soil 

 according to the information desired. The soil can be mixed until 



Fig. 56. Pot experiments. New Jersey Station. 



Fig. 57. Protection of pot experiments from inclement weather. 

 New Jersey Station. 



uniform, and the pot supplied with a favorable amount of water, 

 kept at a favorable temperature, and the crops protected from 

 damage by insects, birds, or storms. The conditions can be more 

 1 Exp. Sta. Record 7, p. 77; 5, p. 849. 



