84 Effective Farming 



tains about 6.5 to 7 per cent nitrogen, 2.8 per cent phosphoric 

 acid, and 1.8 per cent potash. Because of its value as a stock 

 feed and its high price, it is better practice usually to feed 

 the meal to live-stock and apply the resulting manure to the 

 soil than to use the meal as a direct fertilizer. 



Linseed meal. A product of flaxseed, linseed meal, con- 

 tains about 5 per cent nitrogen, but like cottonseed meal, it is 

 so high in price and so valuable as stock feed that it is not 

 often used as fertilizer. 



Fertilizers from the atmosphere. The artificial fixation of 

 atmospheric nitrogen has been accomplished with some suc- 

 cess. A product known by the trade name cyanamid is 

 now on the market. It contains about 16 per cent nitrogen. 

 The nitrogen is not readily available, but becomes so in the 

 soil. By many it has been used with good results. In Nor- 

 way a product known as calcium nitrate is made by fixing 

 atmospheric nitrogen; but its manufacture is not conducted 

 extensively on a commercial scale in the United States. The 

 product contains nitrogen in an available form for plants. 

 The electric arc is used in converting the nitrogen into the 

 calcium nitrate. 



36. Phosphatic fertilizers. In normal times available phos- 

 phorus in commercial fertilizer costs from four to five cents a 

 pound. The chief sources are animal bones, natural deposits 

 of phosphate rock, and by-products from the manufacture of 

 steel from phosphatic iron ore. 



Bone-meals. The animal bone-phosphates are raw bone- 

 meal and steamed bone-meal. Raw bone-meal consists of 

 untreated bones ground to a powder. Steamed bone-meal 

 is made of bones after the fat has been removed by steam. 

 The steaming makes it possible to grind the bones finer and 

 the absence of fat causes the material to decay rapidly, both 

 of which are advantages. Raw bone-meal contains about 9 

 per cent phosphorus and 4 per cent nitrogen. Steamed bone- 

 meal contains from 12 to 14 per cent phosphorus and from 1 



