ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



251 



ready exclaimed to themselves what nonsense ! " Can't be done." 

 But it can, and should. And it can be done in this way: 

 Get the forms of phosphoric acid — best in bone ash, the 

 forms of nitrogen, best as sulphate of ammonia, or dried 

 blood or nitrate of soda, the forms of potash. Lay out 

 some plots in the field, all of the same size. To one 

 plot apply one of these substances, say phosphoric acid, to 

 another nitrogen, to another potash, to another phosphoric acid 

 and nitrogen, to another potash and nitrogen, to another phos- 

 phoric acid and potash, to another apply all. Grow crops upon 

 the plots, carefully harvest and weigh them. The quantities 

 yielded by the several crops will vary and the variations will 

 serve to show what substances must be added to the soil of the 

 field experimented upon in order to produce the best crop. And 

 after all the farmer will have made a practical chemical analysis 

 of his soil. 



An illustration of this is found in an experiment made on the 

 experiment station at Gembloux, in Belgium, upon clay soil and 

 sandy soil : 



Nitrogen produced. 



N.+P 2 O5 

 N. + P 2 5 ,K 3 O 



ON THE CLAY SOIL 



Per cent, increase. 



146 to 150 

 i46 " 150 

 146 " 150 



ON SANDY SOIL. 



Nitrogen produced. 



N.+P 3 O5 

 N. + P 3 05,K 2 0. 



Per cent, increase. 

 150 to 250 

 " 37o 



330 

 480 



524 



The clay soil required then nitrogen, but no phosphoric acid 

 or potash, while the sandy soil required all. 



So, too, the director of the Experiment Sation of New Jer- 

 sey, induced the farmers of that state to make similar experi- 

 ment, with expenditures for nitrogen which in this state would cost 

 $1.76, for phosphoric acid $3.25, and potash $3.20, to be applied 



