40 Journal of Agriculture, Victoria. [10 Jan., 1918. 



Bonedust containing — 



Nitrogen . . . . 4.00 per cent. 



Phosphoric acid . . . . . . 18.00 per cent. 



Mechanical condition — 



Fine bone . . . . . . . . 33.00 per cent. 



Coarse bone . . . . . . . . 67.00 per cent. 



Nitrogen in Fine Bone . . . . 4.00 X 33 



100 

 Nitrogen in Coarse Bone .. .. 4.00 X 6~ 



100 

 Phosphoric Acid in Fine Bone ., 18.00 x 33 



lOJ 



Phosphoric Acid in Coarse Bone .. 18.00 X 67 



lOij 

 Per cenl . Unit-Value. Value per ton 



Nitrogen, fine bone . . 1.32 X 16s. Os. £112 



Nitrogen, coarse bone .. 2.68 X 14s. Os. fl 17 6 



Phosphoric acid, fine bone . . 5.04 X os. Od. £1 !) 8 



Phosplioric acid, coarse bone 12.06 X 3s. 6d. £2 2 3 



Total . . . . . . £6 10 7 



= 1 .32 per cent. 



= 2.68 per cent. 



= 5.94 per cent. 



= 12.0o per ce;it. 



Besides the slight variation in the method of calculating the value 

 per ton of these fertilizers, the foregoing illustration is intended to 

 draw attention more directly to the difference in the form of guarantee 

 required for these fertilizers. 



Bonedust is a fertilizer made from crushed or ground bones, and its 

 value depends largely on (a) the percentage of nitrogen and phosphoric 

 acid it contains; (b) the degree of fineness of the particles of bone. 



Bone fertilizers differ from bonedusts in that they contain other 

 materials, such as gypsum, marl, superphosphate, and rock phosphate. 

 The latter material is added on account of its high phosphoric acid 

 content. The addition of rock phosjihate does not tend to make the 

 fertilizer as available as one made wholly from bone. Therefore, no 

 brand is registered as a bonedust Avhich contains any of the materials 

 mentioned. 



Basic Phosphate. 



This fertilizer is of recent introduction, and owes its appearance 

 on the list of published brands to the shortage of supply of Thomas 

 Phos]5hate. It is prepared locally by mixing superphosphate with 

 sufficient lime to neutralize all the free acid, and convert the super- 

 phosphate into a less soluble form. Superphosphate so treated contains 

 its phosphoric acid mainly as citrate soluble, and thus bears some 

 resemblance to Thomas Phos]ihate, but differs therefrom, however, in 

 the degree of fineness of its particles, being much coarser grained. The 

 finer the particles composing a fertilizer, the more surface will be exposed 

 to the action of the various agencies in the soil. Superphosphate, when 

 applied to the soil, undergoes a process of reversion. The phosphoric 

 acid of the superphosphate is mostly sohible in water. When super- 

 phosphate is applied to land, the soil water will dissolve the phosphate, 

 and bathe, within certain limits, the particles of soil it may reach. 

 Meeting with small particles of lime, iron, and alumina oxides, it 

 enters into combination with them and reverts to a less soluble 

 condition, and is deposited as a thin coating. A more intimate mixture 

 is obtained with the soil by superphosphate than would be got through 



