Manures and Fertilizers 117 



factiired into many branda of mixed fertilizers, usually 

 being prepared for some special crop or soil. Both the 

 materials and mixed fertilizers are sold under statement 

 of definite percentages of the plant-foods they contain. 

 Annual state inspection and analysis show that these 

 statements are usually reliable. Each has advantages 

 for farmers' use. The mixed factory goods are usually 

 in good mechanical condition for sowing and are generally 

 kept or can be soon obtained from dealers. These dealers 

 usually extend credit to buyers. The manufacturers 

 contend that by the wet or acid process they are liable to 

 utilize materials too insoluble for use directly by crops. 

 The many trade brands for the same crop may differ 

 greatly in composition ; and often a number of brands 

 having the same analysis are sold as "special fertilizers" 

 for widely varying crops. 



The variation between soils is so great that the same 

 crop raised on different lands may require widely varying 

 fertilizers for the best results. Only experience and careful 

 study will show what these requirements are. Such study 

 and observation are rather rare in America. In Europe, 

 farmers are more accustomed carefully to mix their ferti- 

 lizers according to the special needs of each combination of 

 soil and crop. In Germany this goes so far that the mate- 

 rials are often applied separately at the most favorable time 

 for the action of each, although this would not be advisable 

 here on account of greater cost of labor. The materials 

 used by farmers in home mixtures are usually of high grade. 

 Sometimes, as with nitrate of soda, acid phosphate and muri- 

 ate of potash, a mixture that is of the right analysis for a 

 particular crop may be composed of materials that are 

 sticky in combination and do not drill well. Care must 

 often be taken to include materials like dried blood, tank- 



