PHOSPHATE FERTILIZERS 165 



the absence of phosphates ; an imperfect supply re- 

 sults in the production of light weight grains. The 

 nitrogen and phosphates are to a great extent stored 

 up in the same parts of the plant, particularly in the 

 seed, which is richer in both nitrogen and phosphorus 

 than is any other part. Nitrogen is the chief element 

 of protein, while phosphorus is necessary to aid in 

 transporting the protein compounds through the cell 

 walls of plants. In speaking of the phosphorus in 

 plants and in fertilizers, as well as in soils, the term 

 phosphoric acid or phosphoric anhydride is used. 

 This is because phosphorus is an acid-forming ele- 

 ment and, as already explained, the anhydride of the 

 element is always considered instead of the element 

 itself. 



211. Amount of Phosphoric Acid Removed in 

 Crops. The amount of phosphoric acid removed 

 in an acre of different farm crops ranges from 18 to 30 

 pounds : 



Phosphoric acid 

 per acre. 

 Lbs. 



Wheat, 20 bu 12.5 



Straw, 2,000 Ibs 7.5 



Total . 20.0 



Barley, 40 bu 15 



Straw, 3,000 Ibs 5 



Total 20 



Oats, 50 bu 12 



Straw, 3,000 Ibs 6 



Total 18 



