FARM ARITHMETIC 



CHAPTER I. 

 PLANT FEEDING. 



Farming profits are derived directly and indirectly 

 from the soil ; directly through the growing of plants and 

 indirectly through the feeding of animals. The wise 

 farmer, therefore, gives much thought to the care and en- 

 richment of the land. Although the greater part of the 

 substance actually entering into the growth of plants 

 comes from water and air, all plant growth may be said 

 to depend upon the soil. The comparatively small part 

 which comes from the soil is absolutely essential to the 

 growth of the plant and must be present in a sufficient 

 quantity and in the proper form. 



Where plants get their food. The young plant be- 

 ginning its life obtains its first food from the seed. With 

 this food it starts its roots into the soil and its stems and 

 leaves into the air. Both roots and leaves begin imme- 

 diately to gather food for further growth. 



The leaves take from the air carbon and oxygen. 



The roots take from the soil water (oxygen and hydro- 

 gen), nitrates (nitrogen), phosphoric acid (phosphorus), 

 potash (potassium), lime (calcium), iron, sulphur, sodi- 

 um, chlorine, magnesium, silicon, manganese, etc. 



Composition of plants. A mixture of all kinds of 

 plants after having all moisture driven off by heat, con- 

 tains the following percentages of elements : 



