New York Agricultural Experiment Station. 



47 



called potash compounds^ because it was formerly supposed that 

 potassium oxide or potash was present in all of them. 



Potassium combined with chloride forms potassium chloride or 

 chloride of potash or muriate of potash, etc. Potassium and sul- 

 phuric acid form potassium sulphate or sulphate of potash. Potas- 

 sium and nitric acid form potassium nitrate, also called nitrate of 

 potash and saltpeter. 



Sodium. — Occurrence. — Sodium occurs in nature mostly in com- 

 bination with the element chlorine in the form of sodium cholride 

 or common salt. It is found everywhere in the soil, but usually in 

 small quantities. Sodium and nitric acid form sodium nitrate or 

 nitrate of soda, commonly known as Chili saltpeter. 



Magnesium, Iron and Manganese. — These elements, especially 

 magnesium and iron, are present as essential constituents of plants. 

 They exist in various forms of combination with other elements. 



2. Classification and Definition of Terms used in Connection 



WITH Fertilizers. 



A Fertilizer may he defined as any substance which, hy its addi- 

 tion to the soil, is intended to produce a better growth of plants. 



The materials which come under the head of fertilizers are 

 numerous in kind, and different both in form and the manner in 

 which they act. 



The following tabulated classification, while not strictly accurate 

 in every respect, will serve to give a good general idea of the num- 

 ber and relations of the terms used in speaking of fertilizers : 



FERTILIZERS <^ 



I. Direct 



OR 



Nutritive. 



1. Natural . 



f Stable manure. 

 Refuse vegetable matter. 

 Greeu crops for plowing under. 

 Cotton-seed. 

 Muck, marls, etc. 



{ 



a. Complete or 

 general. 

 2. Jr<iA(na?..<; Chemical, or | *' Incomplete 

 ■' I P^^r^,^^.l ' L ^r Special. 



Commercial, 



I Prepared. 



II. Indirect TLime. 



OR < Gypsum. 



Stimulant. [Salt, etc. 



These terms are, in general, loosely and indiscriminately used, as 

 their meaning is often misunderstood ; and so an attempt will be 



