CHAPTER III 

 AGRICULTURAL SUBSTANCES CARRY FORCE 



At the beginning of a technical study of agriculture 

 the student needs to see clearly that the substances of 

 soil and air, the force constantly sent to the earth by 

 the sun, the organizing forces of heredity in living 

 plants and animals, the willing and the directing powers 

 of man and the needs of the human race are the five 

 great elemental things concerned in the making of farm 

 products. The nations are rapidly awakening to the 

 fact that scientific research, plant and animal breeding, 

 school education, extension teaching and actual demon- 

 stration are destined very greatly to increase the farm 

 production per acre and per farm worker. They are 

 beginning to invest vast sums of money in agricultural 

 advancement as a great corporation invests in improve- 

 ments in its business. The farmers are arousing them- 

 selves to the full value of new knowledge, superior plant 

 and animal forms, and to systematic training for the call- 

 ings of farming and farm home making. 



Plant compounds are storage batteries. Plant materials 

 consist of compounds of the elements gathered from the 

 soil and air and stowed away during their growth. It may 

 be said that no real growth has been made by a plant 

 until the green appears in the stem or leaf. Before this, 

 the enlargement of the plantlet has been accomplished 

 by using up the food materials stored in the seed. This 

 leaf green, or chlorophyll, as it is called, is made of 

 small oblong bodies called chloroplasts, colored green 

 with a coloring matter termed chlorophyll. These 

 chlorophyll bodies do not appear in plants that are kept 

 in the dark. Seeds and roots that begin growth in the 



