26 



FARM ARITHMETIC. 



Remember. Every farmer should study the nature of 

 soil he is farming and the needs of the crop he is grow- 

 ing. He owes it to himself and to humanity to treat the 

 soil in such a way that it will grow richer and richer 

 rather than poorer and poorer. 



What Corn Takes From the Soil. 



The following problems are intended to serve as a re- 

 view of the -entire subject of plant feeding, and to show 

 what an enormous draft corn, our great king crop, makes 



NITROGEN 



PHOSPHOROUS 



POTASSIUM 



PLANT FOOD IN CORN. 



Relative amounts of nitrogen, phosphorus and potassium required by an average 

 corn crop. 



each year on the plant food stored in the soil. A similar 

 study could be made with wheat, cotton, hay or the lead- 

 ing crop of any section. The principles involved are the 

 same regardless of the crop, season, or section. As a 

 rule, the soil elements required for the growth of plants 

 are abundantly present in the soil except nitrogen, phos- 

 phorus and potassium. These are the principal elements 

 with which the farmer is concerned in feeding his crops. 

 Therefore, fertilizing the land, or feeding the crop, calls 

 for a study of the nitrogen, phosphorus and potassium 

 taken up by the crop and thus removed from the soil. 



