Aug. 3, 1908.] Agricultural (Jrazette of N.S.W. 615 



phosphates, for the manufacture of suj^erphosphates, has been successfully 

 practised, and the enormous influence which the introduction of super- 

 phosphate has had on the development of agriculture may be gathered from 

 the quantity now annually employed by farmers. The annual manufacture 

 of superphosphates in the world is about 6,000,000 tons. 



As regards agricultural needs, it is evident that nitrate of lime, closely 

 related as it is to nitrate of soda, has before it almost unlimited prospects, 

 which are daily increasing. It is already well known that all nitrates of 

 alkaUes or of lime are as good manure as nitrate of soda. 



It occurred to me that rock phosjjhates treated with nitric acid — instead 

 of sulphuric acid — would produce nitrate of lime and water-soluble phos- 

 phoric acid, or nitrated calcium superphosphate. 



In order to test in a practical manner the manurial value of superphosphate 

 manufactured by each acid, some samples were prepared, the procedure 

 being otherwise similar to that usual in the manufacture of superphosphate. 



Some strongly alkaline soil from Moree was procured for the experiment. 

 Fig. 4 illustrates the result, 

 and shows clearly the su- 

 periority of the nitrated 

 phosphates. Pot No. 1), 

 unmanured soil ; No. 10, 

 manured with 5 grammes 

 nitrated superphosphate ; 

 No. 11, manured with 5 

 grammes ordinary super- 

 phosphate. The pots were 

 sown on June 8th, 1907, 

 with four grains of wheat 

 in each pot; germination 

 was excellent. 



Only two plants were 

 allowed to mature in each 

 case. The foUage of No. 9 

 was more yellow than green ; 

 No. 10 was a rich dark- 

 green, and very vigorous; 

 No. 11 was not a healthy 

 green. In view of the extra- 

 ordinary results of this ex- 

 periment, it is only reason- 

 able to assume that the 

 nitric nitrogen corrects the 

 toxic properties of the 

 alkali, and restores the soil Fig_ 4_ 



