DAIRY, SEED IMPROVEMENT, STOCK BREEDERS' MEETINGS. 3OI 



There are no methods of extracting potash from feldspar 

 thus far devised that are economically possible under normal 

 potash prices. While it is 'hoped that supplies of potash may 

 be fo'und that will make this country independent of foreign 

 S'ources, not enough will 'be produced before planting time to 

 at all relieve the present sihortage. 



Outside of a limited amount of ashes, available potash is 

 practically unobtainable for most crops. Commercial fertiliz- 

 ers for 1916 will, for the most part, be made to carry no potas'h 

 or at the most, only one per cent. This one per cent will add 

 five dollars to the cost of fertilizer per ton. 



POTASH LIBERATORS. 



There are no such things as potash substitutes in agriculture, 

 but some materials, such as the sodium and calcium salts, will 

 under certain conditions more or less replace the potash in the 

 soil and render it available for the growing O'f plants. 



Among the soda salts are nitrate of soda, soda ash and com- 

 mon salt. Gypsum (calcium sulphate) is the most important 

 calcium salt. Alkaline sources oi lime and soda such as cal- 

 cium carbonate and lime and of soda ash, do not seem to be so 

 effective in releasing the potash of soils as are the chlorides 

 and nitrates. 



Field experiments conducted for twenty years at the Rhode 

 Island Experiment Station seem tO' indicate that soda has consid- 

 erable value in releasing potash for certain crops. There was 

 very little gained' from the use of common salt with the potato 

 crop. This experiment indicated during its whole course that 

 the application of soda to the granite soils helped to insure the 

 production of normal crops, even without the addition of 

 potash. At the Experiment Station at Rothamsted, England, 

 nitrate of soda 'has been found to be of marked value in the 

 growing of crops, irrespective of the nitrogen which it carries. 

 Doctor Hall, in reviewing this work, states that "It is not suffi- 

 ciently realized hoiw valuable a soda base may be. This is not 

 'because the soda is in any way necessary to the nutrition of the 

 plant but because of the action of any soluble salt upon the 

 insolu/ble potash compounds in the soil. The 'potash in the soil 

 is due to the partial weathering of double silicates like feld- 

 spar and of clay, whic'h is not to 'be regarded as pure kaolinite, 



