FERTILIZERS FOR VEGETABLES 



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proper foundation, that the sulphuric acid which had been 

 used in the refining of kerosene oil and which was then used 

 for making the acid phosphate was prejudicial. 



Question: What proportion of nitrate of soda or lime 

 would it be necessary to put in your acid phosphate in order 

 to counteract any such action? 



Professor Van Slyke : The probability is that if you put 

 on per acre a hundred pounds of nitrate of soda in your fer- 

 tilizer that would be sufficient to prevent acidity from acid 

 phosphate. It may sound strange, but nitrate of soda has 

 the power of preventing or correcting acidity, but it is ex- 

 plained in this way: The nitrate of soda is made up of two 

 parts, the nitrate part and the soda part. Plants do not use 

 sodium to amount to anything. They simply take up the 

 nitrate, and that leaves the sodium in the soil. That at once 

 combines with the carbon dioxide and makes sodium bicar- 

 bonate or saleratus, which is an alkali and neutralizes acids. 



Potatoes Again. 



Mr. Wortley: I should like to ask your advice on some 

 unexpected results I had. In Bermuda castor pomace is 

 used very largely. It is used without phosphate or potash. 

 The soils are very light, calcareous almost entirely. Sand is 

 not known to contain silicon. These soils proved to be de- 

 ficient in potash. They had been used for years in growing 

 potatoes without any rotation, and I thought it would be very 

 easy to use a 4-8-10 formula and get a very superior yield to 

 that of castor pomace. I have been trying that with ten 

 plots, and in five cases the pomace, at the cost of half that of 

 the 4-8-10, has given better results. While I have had very 

 good returns in one or two cases, the popular local manure 

 has beaten the more expensive 4-8-10. 



Professor Van Slyke: Do you know what the condition 

 of those soils was with reference to the amount of organic 

 matter in them? 



Mr. Wortley: It was not very high. 



Professor Van Slyke : With a fairly warm climate, lots 

 of calcium carbonate and frequent replenishings would be 



