146 



AGKICULTUKE. 



The figures given show the approximate losses on a 

 l6o-acre farm under the different rj-stems of farming. 

 With stoclc- and dairy-farming, as well as partly in mixed 

 grain- and general farming, the loss of nitrogen may be 

 avoided by growing clover. In stock and dairy-farming, 

 therefore, no loss of fertility will occur under these con- 

 ditions when all the skim-milk is fed on the farm and a 

 part of the grain is exchanged fur more concentrated milled 

 products, but there will on the contrary be a constant 

 gain of fertility to the soil. (See Bull. 41, Minn. Exp. 

 Station.) 



AVKRAGE CHKMICATi COMPOSITION OF 

 AMERICAN SOILS. 



(King.) 



Fertile soils contain the following percentages of dififerent 

 components, according to Snyder (averages for 200 samples) : 



Per cent 



Insoluble matter 79-95 



Potash 29 



Soda 25 



Lime 2. 16 



Magnesia 55 



Iron oxide 2 . 68 



Per cent 



Alumina S . 20 



Phosphoric acid 24 



Sulphur trioxide 03 



Carbon dioxide 1.12 



Volatile matter 7 . 00 



99-47 



Volatile matter contained: Humus, 3.35 per cent; Nitrogen, 0.29 

 per cent. 



