MIXED FERTILIZERS 



49 



It will be seen in this table that, excepting in the one 

 case of cows giving milk, the proportion returned as saleable 

 is very small indeed. Very nearly the whole of the potassium 

 in the food is returned to the manure heap in a liquid form, 

 easity lost by drainage. The conservation of this potassium 

 is a very important problem, since where there are clay fields 

 the amount of potassium in the soil is natmally large, but 

 where the soil is sandy the potassium is needed as a fertilizer. 



The phosphorus history of the food eaten is given in 

 Table 9, from which it will be seen that the major part of 

 the phosphorus eaten is returned to the manure heap in 

 the solid form, and is, therefore, not easily lost. 



Table 9. — Phosphorus History of Feeding. 



Horse 



Ox 



Pig 



Sheep 



Cow 



Total. 



100 



86 



84 

 86 



77 



Considering the very big increase in crop often produced 

 by phosphatic manures, and considering the very small 

 risk of loss, every possible step should be taken to increase 

 the use of phosphatic fertilizers. Nothing like the amount 

 that ought to be used is applied in common practice. 



Great variation will occur in the composition of the 

 manure, according to the particular system employed. 

 Table 10 shows the comparison between feeding on very wet 

 food and on very dry food. 



These conditions represent extremes, but there is much 

 room for variation between these limits. When very watery 

 food is fed, the amount of liquid manure is nmch increased, 

 and carries with it a bigger quantity of dry material. In 

 both the foods actually selected the amount of potassium 

 is high, and, therefore, there is ample to spare for all purposes. 

 D. 4 



