requirements of the soil and crops. He will then know what he is 

 putting into the soil, and can wait patiently for the results, with a 

 little more certainty of obtaining a crop. 



There is scarcely any doubt that superphosphates will benefit 

 most crops that require phosphoric acid, and give a larger return 

 than insoluble phosphates. From our present knowledge of the 

 soils of Western Australia, I am inclined to think more superphos- 

 phates will be required here than in England, as they are generally 

 poorer than in England as regards phosphoric acid. The crops 

 that are benefited by superphosphates are turnips, potatoes (but 

 not mangolds), wheat, barley, but not so useful for oats. The 

 amounts generally used are for turnips, 3 to 4 cwt. ; potatoes, 4 to 

 6 cwt. in conjunction with potash ; wheat and barley, 3 cwt. per 

 acre. 



Dr. Aitken, of the Highland and Agricultural Society of Scotland, 

 experimented with root crops and bone meal, coprolites and apatite, 

 dissolved and undissolved. The soluble gave an increase of 50 per 

 cent. over the insoluble. Grain crops in a rotation following the 

 roots, showed the effect of the soluble phosphates, increasing the 

 yield of grain 15 per cent, and straw 12 per cent., clearly proving 

 that the roots did not exhaust the soluble manure. 



Professor J. M. Cameron obtained an increase of 39 per cent, 

 with root crops for soluble as against insoluble phosphates. 

 Although superphosphates will benefit most crops, they are not of 

 much benefit in soils that are poor or very deficient in lime, owing 

 to the want of the necessary base to render* the soluble phosphates 

 insoluble ; the soluble phosphates having an acid reaction which 

 injuriously affects the young plant. This is putting an extreme case, 

 as there are few soils so deficient in lime that they cannot fix the 

 soluble phosphates. This acidity in the superphosphates is reduced 

 to a minimum by the use of dryers in the finishing of the manure. 

 Twenty-five to thirty years ago, they were so badly made that there 

 was scarcely a superphosphate in the market that did not contain 

 free sulphuric acid. Looking over my laboratory note-book of the 

 analyses of superphosphates and dissolved bones sent by members 

 of the Highland and Agricultural Society, Scotland, for icSjj, the free 

 sulphuric acid ranges from a trace to 6 and 7 per cent. 



The following are average samples of superphosphates and 

 dissolved bones as supplied to the market at the present time: 



Mineral Dissolved 



Superphosphate. Bones. 



Moisture ... ... in-J4 I2X>6 



1 Organic matter ... S-gy >_' - o6 



Soluble phosphates ... '74- '4'^5 



Equal to tricak-ic plms- / ,_. 



phatc rendered soluble \ 



Insoluble phosphates ... 3'oS -O'95 



