30 



cost of the potash and the increased value of the crop, some 

 $6,000,000. 



This is but one out of many instances that might be given as 

 to what might be done by proper rational fertilization 



NEVER USE POTASH ALONE. 



The success of the various potash salts, as fertilizers, depends 

 upon their proper application. They should never be used 

 alone, because they only furnish one important element of plant 

 food ; the full effect of potash fertilization is only obtained 

 in connection with a proper supply of phosphoric acid and 

 nitrogen. 



In a general way practice and experience has established the 

 following rules for their use : On low, peat soils, rich in nitrogen, 

 the application of nitrogen is unnecessary, and also when the 

 nitrogen has been supplied by green manuring; that is to say, 

 by planting peas, etc., and inducing them, by a liberal supply 

 of potash and phosphates, to an increased absorption of nitrogen 

 from the air, and ploughing them under. Except in these two 

 cases nitrogen should always be with the potash and phosphates 

 supplied to the soil. 



The potash salts act, to some extent, as a solvent upon the 

 phosphates, and the use of Thomas slag has proven particularly 

 successful in connection with potash. 



In soils deficient in lime it is quite essential, when applying 

 potash, to give them also the requisite amount of lime. 



Potash salts should never be applied as a top dressing; they 

 should be applied as early in the Fall as possible and worked 

 into the ground by deep ploughing. 



