IDEAL FERTILIZERS 53 



of slight value were this element not fully supplied by 

 the low grade sulphate of potash, and the manganese 

 would be harmful were there enough to make any dif- 

 ference, but there is not, so the buyer can be assured that 

 none of these elements are going to hurt or benefit him 

 and reckon the phosphate powder worth just what its 

 content of phosphoric acid and lime is worth to him. Be- 

 ing inorganic this material is not a soil builder. It has 

 an alkaline tendency. 



High Grade Sulphate of Potash is inorganic, carrying 

 water soluble potash which is immediately fixed in the 

 soil in form available to plants. When the potash is used 

 by the plant the sulphuric radical is left to seek another 

 base. Sulphate of potash is practically the only source 

 of potash at the citrus growers' command, but few for- 

 mulas derive their entire potash content from the high 

 grade. 



Low Grade Sulphate of Potash Since several have 

 written to ask, it may be well to state that "double sul- 

 phate of potash magnesia 77 is simply another name for 

 our old friend low grade sulphate of potash, which is the 

 standard source of potash supply. This material carries 

 about half as much sulphate of potash as the high grade, 

 and has about thirty-four per cent, sulphate of magnesia, 

 which was taken up under Fads. 



Muriate of Potash and Kainit carry potash in water 

 soluble form but have a high content of chlorine. Citrus 

 trees are sensitive to the ill effects of chlorine. Vegeta- 

 bles generally are not. Chlorine is repulsive to soil in- 



