ARTIFICIAL MANURES OR FERTILIZERS. 103 



2. The using of one or more of the constituents as 

 may be found to be necessary, thus avoiding the expense 

 of purchasing and applying those not required for the 

 particular crop or soil. The farmer is also enabled to 

 adjust the forms and proportions of the various ingre- 

 dients to suit what he has found to answer the needs of 

 his soil or crop. 



3. A saving in the cost of plant-food, since in their 

 concentrated form the expenses of handling, shipment, 

 bagging, etc., are reduced. 



The chief disadvantages in the buying and use of 

 incomplete fertilizers are : — 



1. They are not so generally distributed among dealers, 

 and thus not so readily obtained. 



2. It is difficult to spread evenly and thinly products 

 of so concentrated a character, particularly the chemical 

 salts, which, unless great care is used, may injure by 

 coming in immediate contact with the roots of plants. 



3. The mechanical condition, or degree of fineness, is 

 less perfect than in the manufactured products. 



The advantages in the purchase and use of complete 

 manures are : — 



1. They are generally distributed, and can be purchased 

 in such amounts and at such times as are convenient. 



2. The different materials may be well proportioned, 

 both as to form of the constituents and their relative 

 amount for the various crops. 



3. The products are, as a rule, finely ground and well 

 prepared for immediate use. 



The chief disadvantages are : — 



1. That it is impossible to detect in a mixture whether 

 the materials are what they are claimed to be, 



