Food for FARMERS' BULLETIN No. 107. 



Plants 



218 Prepared in the Office of Experiment Stations, 



Washington, D. C. 



'Under existing conditions farmers are advised to 

 purchase fertilizer materials and to make their own mix- 

 tures rather than to purchase mixed or complete special 

 fertilizers. This course is believed to be advisable for 

 two reasons: First, because the 'specials' are not 

 properly compounded, and second, because the needed 

 plant food can be thus procured at lower cost."* 



The continuous use of muriate of potash may so far 

 deplete the soil of lime that an occasional application 

 of this material may be required in the case of such use. 

 The sulphate of potash is a safer material to use 

 where a growth of clover is desired than the muriate, 

 and therefore it may often be wise to use the sulphate. 

 The high-grade sulphate should be selected. 



These materials should as a rule be mixed just 

 before use, and applied broadcast (after plowing) and 

 harrowed in just before planting the seed. Where Ni- 

 trate of Soda is to be used in quantities in excess of 150 

 pounds per acre, one-half the amount of this salt may be 

 withheld until the crop is 3 or 4 inches high, when it may 

 be evenly scattered near the plants. It is unnecessary 

 to cover this, though it may prove more promptly 

 effective in absence of rain if cultivated in. 



The quantities recommended are in most cases 

 moderate. On soils of good physical character it will 

 often prove profitable to use about one and one-half 

 times the amounts given. 



Terms Used in Discussing Fertilizers. 



Nitrogen may exist in three distinct forms, viz.' 

 as Nitrates, as Nitrogenous organic matter, as am- 

 monia salts. 



Nitrates furnish the most readily available forms 

 of Nitrogen. The most common is Nitrate of Soda. 



Nitration, or Nitrification, is the process by which 



*U. S. Department Agriculture Farmers' Bulletins, 65 and 84 (Experiment 

 Station Work, II, page 27; VII, page 5). 



