36 MANUFACTURE OF FERTILIZING MATERIALS 



phosphates and soluble potash salts. Fertilizers 

 which dissolve easily and diffuse through the soil 

 rapidly and which are not readily retained by the 

 soil, are best applied only when the crops are 

 ready to utilize them. If put on too early, there 

 is danger of their leaching from the soil and being 

 carried away beyond the reach of the plant, and 

 thus lost. Hence, it is not wise ordinarily to 

 apply guano, ammonia compounds or nitrate of 

 soda in the fall, except in climates which have a 

 dry fall and winter. Their application should be 

 deferred until spring. In wet springs, ammonia 

 compounds are preferably applied rather than 

 nitrate of soda; or, if nitrate of soda is used, loss 

 may be avoided by making several small applica- 

 tions instead of one at the start. 



In applying highly concentrated commercial 

 fertilizers, it is wise to prevent the fertilizer coin- 

 ing in contact with the seeds or foliage of plants. 

 Fertilizers containing ammonia compounds should 

 not be mixed with wood ashes, lime, or Thomas 

 slag (odorless phosphate), since some of the 

 ammonia is likely to be lost. 



