lo Aug., 1911.] Artificial Manures Acts. 559 



4. Mixed Manure. Invoice certificate or tag : — 

 Nitrogen as sulphate of ammonia 

 Piiosphoric acid — 

 Water soluble 

 Citrate soluble 

 Citrate insoluble 

 Potash as muriate (chloride). 

 Calculation — 



IGO X 14s. 9d. = 

 11-50 X 4s. 8d. = 

 - 65 X 4s. = 

 1-25 X 3s. = 

 1-50 X 4s. 6d. = 



Calculated value per ton . . . . . . . . 4 10 4 



General Remarks. 



All substances containing nitrogen, phosphoric acid, or potash,, 

 manufactured or prepared for the purpose of fertilizing the soil or sup- 

 plying nutriment to plants, come under the operation of the Artificial 

 Manures Acts. As regards nitrogen, we find the chief supply in three dif- 

 ferent chemical forms, namely, nitrate, ammonia, and organic. In the 

 nitrate state it is combined with sodium, forming nitrate of soda, which 

 is readily soluble in water, and is in a condition immediately available 

 for plant nutrition. As ammonia, it combines with an acid radicle, form- 

 ing sulphate of ammonia, which is also soluble in water, but is not so 

 readily assimilated by the plant as the nitrate, and its action is conse- 

 quentfy slowei in efrect. In the organic form, nitrogen is found in dried 

 blood, bonedusts, and other organic substances. In this state, it is in- 

 soluble in water, and therefore slowest in action, but it is not so liable 

 to loss by seepage as the two first-mentioned forms. In addition to the 

 above-named substances, new materials possessing nitrogenous properties 

 are being introduced, such as nitrate of lime and cyanamide of calcium; 

 both of these contain lime as a base, and are likely to be of considerable 

 value as fertilizers in the future. 



Phosphoric acid appears under three headings (water soluble, citrate 

 .soluble, and insoluble), and these terms express the forms in which phos- 

 phoric acid is readily available, moderately so, or difficultly so, respec- 

 tively. The first-mentioned form is, of course, soluble in water, the 

 second is the portion soluble in citrate of ammonia after the extraction of 

 the water soluble content. Citrate soluble form is generally considered to 

 be available as plant food, and is of importance in arriving at the value 

 of a fertilizer. The insoluble phosphoric acid is not of any immediate 

 value to the plant, its action on soils is slow, and its use doubtful. Ex- 

 perience has shown the necessity of fertilizers, which are immediately 

 available to the plant, and for this reason insoluble phosphate is treated 

 with sulphuric acid, and so converted into soluble superphosphate. 



In bonedusts, bone fertilizers, and mixed manures, there is a consider- 

 able and varying proportion of phosphoric acid in the insoluble state. 



In Thomas phosphate, the phosphoric acid is contained in an available 

 form. It possesses also a small percentage of free lime, and has qualities 

 quite distinct from ordinary superphosphate, which is more readily 

 .soluble. 



In all potash fertilizers the potash is of a uniform, roadily available, 

 rh a racier. 



•Appendi^d is a list of all fertilizers registered in the office of the Sec- 

 retary for .Agriculture for the year 1911, showing the particulars of eacW 

 manure, as required hv fhf Art to bo published in the GoTerumeni Gazette. 



