(388 Agricultural Journal of Victoria. 



aro 



It will be observed tliatthe diiferences in favor of superphosphate 

 .„^ siiurularly reguhir — in fact almost identical in the first three 

 coniparisons— anf a larger increased yield of l-5th of a ton to the 

 acre might apparently be accepted as the minimum obtained from 

 2 cwt. over a like quantity of Thomas phosphate. 



BoNEDUsT Compared with Suierfhosfhate and Thomas Phosphate. 



In the returns of the preceding year (1902-3) the yields of hay 



obtained from equal quantities of the three phosphatic manures, 



taking an average of the 30 fields, were as follows : — 



2 cwt. Superphosphate. 



Tons. 



2-32 



2 cwt. 

 Thomas Phosphate. 



Tons. 



2-18 



, . „ , . I Average of all 



2 cwt. Bonedust. Unmamfred Plots. 



Tons. Tons. 



214 1-66 



In this case the average yield of the bonedust plots was below 

 that of both superphosphate and Thomas phosphate. The returns' 

 of last year, however, indicate a marked improvement in the relative 

 position held by bonedust. The more eifective action is undoubtedly 

 due, pi-incipally, to the copious rains of last year, but partly also to 

 an improvement in the mechanical condition of last year's manure 

 sample. In the preceding year it will be remembered that extremely 

 drv conditions prevailed. The fairly high nitrogen content of our 

 bonedusts, an almost universal response of Southern soils to this 

 ingredient, and a growing improvement in the mechanical condition 

 of the manure, evidenced by a larger percentage of fine material 

 than formerly, will help to lift this manure, should it show no 

 unfavorable variation in quality, into a far higher relative position in 

 the South, as regards its operative effect with respect to superphos- 

 phate, than it holds in the North. It is doubtful, however, in a 

 season of ordinary rainfall whether, even with the improvements in 

 the mechanical conditions referred to, a high grade sample, used in 

 e([ual quantity, will show an operative effect quite equal to that of 

 the high grade superphosphate. In a season of abundant rainfall the 

 returns of last year would appear to indicate that the returns of the 

 two would show no great differences. 



Yields of Hay in Tons Secured on Plots jManured with 2 cwt. 

 OF Superphosphate, Thomas Phosphate, and Bonedust in the 

 Season 1903-4. 



Superphosphate. 



2-04 



Thomas Phosphate. Bonedust. 



1-83 I 1-96 



The analysis of the bonedust used in the experiments showed the 



following composition as already stated in an earlier part of this 

 paper : — 



Phosphoric acid ... ... ... 20-85% 



Nitrogen 3-87% 



mechanical analysis. 



Coarse bone ... ... ... 62-53% 



Fine bone ... ... ... ... 37-47% 



