34 MANUFACTURE OF FERTILIZING MATERIALS 



Sulphate of ammonia is a quick-acting nitro- 

 genous fertilizer, but should be used only when the 

 soil has been lately limed. All forms of potash 

 are equally available, but should be applied as 

 early in the season as possible; even fall applica- 

 tions are advisable, as there is little danger of loss 

 through drainage. Lime also aids the effective- 

 ness of potash salts. Phosphates in the form of 

 superphosphate or acid phosphates are very 

 quickly available, resembling nitrate of soda in 

 this respect, though it is hardly advisable to make 

 more than one application, early in the season or 

 at planting time. All other forms of phosphates 

 are best applied in the fall, or very early in the 

 spring. 



It will generally be found more economical to 

 purchase fertilizing materials of high grade. In 

 applying fertilizers, bulk is often desirable, but in 

 purchasing commercial fertilizers, the object should 

 be to secure as much nitrogen, potash and phos- 

 phoric acid in available form as possible, for one 

 dollar, instead of as many pounds as possible of 

 fertilizers, regardless of the amount of plant food 

 contained in it. This is particularly applicable 

 to mixed fertilizers. Since there is a smaller 

 bulk to handle in mixing, a smaller number of 

 packages for holding and, consequently, less 

 weight and freight, it is, as a rule, more economical 

 to purchase fertilizers in their more concentrated 

 forms. For illustration, it is more economical to 

 purchase one ton of high-grade fertilizer than 



