PROFITABLE FARMING 5 



in the least abundance. No excess in the 

 supply of any of the other plant food can 

 possibly compensate for this deficiency. Thus, 

 no excess of phosphates can atone for a deficiency 

 in nitrogen, nor can an excess of nitrogen take 

 the place of a lack of phosphates. 



How to Supply these Plant Foods 



Farm-yard manure, dung, or yard manure is a 

 complete natural manure, containing nitrogen, 

 phosphates, and potash, which are 

 present in varying proportions ac- 

 cording to the feeding and age of 

 the animals producing it, as well as other con- 

 ditions, the principal one being the care that 

 has been taken of it. 



But, though a complete manure, it is not a 

 well-balanced one, as it is invariably richer in 

 both nitrogen and potash than it is in 

 phosphate, the latter substance being ? unfl m d I e ~ 



, v i r jv ficient in 



retained by the animals for the pro- p h08 p h ates. 

 duction of their bones, muscles, milk, 

 &c. Farm-yard manure is comparatively poor 

 in phosphates. 



Moreover, it is a slow-acting manure ; its 

 effects are spread over a number of years. At 

 the Rothamsted Experiment Station this is to be 

 seen on the grass-land where farm-yard manure 

 was applied regularly for some years, but for 

 upwards of forty years afterwards, although it 

 has received no farm-yard or any other manure, 

 the effects are still visible. 



