SECTION IV. MIXED FERTILIZERS 



As a general rule both crops and soils will demand a 

 mixture of the crude fertilizers, and there are many occa- 

 sions on which it is convenient to be able to purchase 

 ready-made mixtures of these crude materials. The chief 

 difficulty that occurs in the application of crude fertilizers 

 is in their even distribution over the land. It is, there- 

 fore, advantageous to obtain a material which is not too 

 concentrated in any one ingredient. Hence there is a 

 distinct advantage in obtaining several materials ready 

 mixed. As, however, the requirements of soils and crops 

 are very varied, and climatic conditions will modify the 

 needs of any particular crop or soil, it becomes practically 

 impossible to design a mixture for any large group of districts, 

 soils, or crops. Certain general principles are quite well 

 established, (i) nitrogen for cereals, phosphorus for roots, 

 potassium for pulses, and (2) phosphorus for heavy soils, 

 and potassium for light soils. But it is quite impossible to 

 adhere rigorously to any such system, because in practice 

 a succession of crops are grown, and what is left over from 

 one crop is used up by the next. Nevertheless, there is 

 a distinct demand for specific mixtures. A very popular 

 mixture is potassic super-phosphate blended so as to contain 

 about 20 per cent, soluble phosphate, and about 3 per cent, 

 potash. Such a mixture can be made in a dry form, handier 

 for distribution than either of its ingredients alone. Mixtures 

 of super-phosphate, sulphate of ammonia, and potash salts 

 are often made and sold under specific names, such as " Corn 

 Manure/' "Grass Manure," or "Turnip Manure." Too 

 much attention should not be given to the name. Estimates 

 should only be based on the guaranteed analysis. Provided 



