238 



Bureau of Farmers' Institutes. 



been exposed to the weather or leached, they contain much less 

 potash, often only 1 or 2 per cent. Ashes from lime-kilns and 

 brick-kilns are generally so mixed with refuse matter as to possess 

 little value for use as fertilizers. Goal ashes possess little value 

 for the potash contained in them, for it is very small. 



Green Sand Marl of New Jersey contains, on an average, 

 about five per cent, of potash, which is in an insoluble form, and 

 is, therefore, slow in acting as a fertilizer. 



Below we present a tabulated summary, showing the amount of 

 potash contained in different commercial fertilizing materials: 



Approximate Amount of Potash in Fertilizing Materials. 



Materials Containiug Potash. 



J. 



D 



O cS 

 +^> 



+* s 



B P< 



<D— . 

 C> eg 



<u 

 Ph 



]*gc3 



So a 



" 2 £3*3 



t$ 2-2 



Ph 



Garnallite 13 to 14 2 GO to 2S0 



Cottonseed-hull ashes 15 to 25 300 to 500 



Kainit 12 to 14 240 to 280 



Krugite 8 to 9 1G0 to 180 



Muriate of potash (SO to 85 per cent.) 50 to 53 1000 to 1000 



Nitrate of potash 43 to 44 860 to 880 



Sulphate of potash (low grade) 28 to 30 500 to G00 



Sulphate of potash (high grade) 48 to 51 9 GO to 1020 



Sulphate of potash and magnesia 2G to 28 520 to 5G0 



Sylvinit 15 to 16 300 to 320 



Waste from powder works 10 to 18 320 to 3G0 



Wood ashes (unleached) 4 to 8 80 to 1G0 



Wood ashes ( leached ) 1 to 3 20 to 60 



(d) Farm-Produced Fertilizing Materials. 



Economic Value of Farm Manures. — A fair estimate of 

 the fertilizing value of the manure annually produced by the 

 farm animals of the United States places the sum at the enormous 

 figure of over two thousand million dollars. This estimate is 

 based on the number of farm animals and on the amount of nitro- 

 gen, potash and phosphoric acid excreted in their manure. The 

 values given to these forms of plant food are those commonly as- 

 signed to them in the form of commercial fertilizers. It will 

 thus be readily seen that the farm-produced manures assume an 

 economic importance which has not been accorded them by the 

 average farmer. 



