SOILS AND FERTILIZERS 521 



Authorities Consulted. Md. E. S. B. 110; F. B. 77; Bu. Pit. 

 Ind. 1, 21; Mass. E. S. B. 137; Cornell Univ. B. 7; W. Va. E. S. B. 

 80; Wash. E. S. B. 19; Va. E. S. B. 187; Tenn. E. S. B. 86; R. I. E. 

 S. B. 96; 0. E. S. Bs. 79, 159; N. H. Ag. Col. Bs. 13, 83; Mich. Ag. 

 Col. B. 11; 111. Univ. B. 116; Purdue Univ. B. 10; Ala. Agr. Dept. 

 Bs. 2, 9;Fla. E. S. B. 2. 



TERMS USED IN DISCUSSING FERTILIZERS. 



Complete fertilizer is one which contains the three essential 

 fertilizing constituents, i. e., nitrogen, phosphoric acid, and potash. 



Nitrogen exists in fertilizers in three distinct forms, viz., as 

 organic matter, as ammonia, and as nitrates. It is the most expen- 

 sive fertilizing ingredient. 



Nitrates furnish the most readily available forms of nitrogen. 

 The most common are nitrate of soda and nitrate of potash (salt- 

 peter) . 



Nitrification is the process by which the highly available ni- 

 trates are formed from the less active nitrogen of organic matter, 

 ammonia, salt, etc. It is due to the action of minute microscopic 

 organisms. 



Phosphoric acid, one of the essential fertilizing ingredients, is 

 derived from materials called phosphates. It does not exist alone, 

 but in combination, most commonly as phosphate of lime in the 

 form of bones, rock phosphate, and phosphatic slag. Phosphoric acid 

 occurs in fertilizers in three forms soluble, reverted, and insoluble 

 phosphoric acid. 



Superphosphate. In natural or untreated phosphates the phos- 

 phoric acid is insoluble in water and not readily available to plants. 

 Superphosphate is prepared from these by grinding and treating 

 with sulphuric acid, which makes the phosphoric acid more availa- 

 ble to plants. Superphosphates are sometimes called acid phosphates. 



Potash, as a constituent of fertilizers, exists in a number of 

 forms, but chiefly as chlorid or muriate and as sulphate. All forms 

 are freely soluble in water and are believed to be nearly, if not quite, 

 equally available, but it has been found that the chlorids may in- 

 juriously affect the quality of tobacco, potatoes, and certain other 

 crops. The chief sources of potash are the potash salts from Stassfurt, 

 Germany kainit, sylvinit, muriate of potash, sulphate of potash, 

 and sulphate of potash and magnesia. Wood ashes and cotton-hull 

 ashes are also sources of potash. 



TERMS USED IN DISCUSSING FOODS AND FEEDING STUFFS. 



Water is contained in all foods and feeding stuffs. The amount 

 varies from 8 to 15 pounds per 100 pounds of such dry materials as 

 hay, straw, or grain to 80 pounds in silage and 90 pounds in some 

 roots. 



Dry matter is the portion remaining after removing or exclud- 

 ing the water. 



Ash is what is left when the combustible part of a feeding stuff 

 is burned away. It consists chiefly of lime, magnesia, potash, soda, 

 iron, chlorin, and carbonic, sulphuric, and phosphoric acids, and is 

 used largely in making bones. Part of the ash constituents of the 



