EFFECT OF SUPERPHOSPHATE ON WHEAT YIELD, N.S.W. 



cropping capacity of a soil, it was hoped that a comparison of the analyses 

 as regards the phosphoric aci'd content of a number of specially chosen 

 wheat soils might reveal some interesting information. 



In his classical work, as a result of which the citric acid method of 

 determining the availability of the phosphoric acid and potash in soils 

 was put forward, Dr. Dyer utilised Rothamsted soils of known cropping 

 powers. He arrived at certain figures which were of value in determining 

 whether English soils were likely to be benefited or otherwise by the 

 application of fertilisers. In our New South Wales wheat belt we have 

 one crop, wheat, to consider ; and as the climatic conditions are to a large 

 extent the same for this belt, it was hoped that a figure might be obtained 

 representing the amount of available phosphoric acid contained in the soil, 

 which would serve to indicate whether the application of a phosphatic 

 .fertiliser is to be recommended or not. 



For the purpose of the investigation, samples of soil were obtained from 

 selected farms in different parts of the wheat belt on which manurial 

 experiments with superphosphate have been carried out. The actual returns 

 obtained from these soils in the manured and unmanured state are avail- 

 able, and as the experiments have been conducted under the supervision of 

 the Inspectors of Agriculture, the figures .quoted are reliable. 



The following is a list of the localities and farms from which the soils 

 were obtained: 



TABLE IT. Showing Source of Soil Samples. 



18* i do 

 21 T. Bragg 

 19* i do 



do 



Mungcribar 

 do 



do 

 do 



do 



* Subsoil. 



The effect of superphosphate en these soils is shown in the following 

 table; the figures are taken from The Agricultural Gazette of New South 

 Wales, 1909 results in Vol. XXI, page 670; 1910 results in Vol. XX IT, 

 Fart 1; and 1911 results in Vol, XXIII, Part 4, 



