AGRICULTURAL JOURNAL OF VICTORIA. 



JULY, 19 0-4 



FIELD EXPERIMENTS IN MANURING, 1903-4. 



By F. J. Hou-ell, Ph.D. 

 1. Hay Manuring Experiments. 



Continued from page 592. 



Superphosphate Compap.ed with Thojia« Phosphate. 



The tests of tlie preceding' year appeared to indicate that Thomas 

 phosphate, used in the same quantity as superphosphate, would more 

 closely approach the latter in effective power, under the more favoi'- 

 able moisture conditions of the South than under those obtaining in 

 the North. Assuming that a high grade article of Thomas phosphate 

 will always be obtained on the market, there appears further evidence 

 in the present year's returns to strengthen this opinion. But this 

 fertilizer unfortunately has shown a tendency to vary in composition, 

 and in the article at our disposal last year the falling off in the 

 percentage of citrate soluble was sufficiently marked to show an 

 effect, in the relatively smaller yields produced, compared with 

 superphosphate. The differences in position of the two manures 

 have also been somewhat widened by slightly higher percentages of 

 phosphoric acid in last year's superphosphate than in the preceding 

 year's sample. Owing to the improvement in the character of some 

 of the recent imported brands and the excellence of the local manu- 

 facture, the bulk of the superphosphates now offering is of a splendid 

 standard, and little more can either be wished for or expected in this 

 direction. As long as Thomas phosphate retains a composition 

 similar to the one used in the experiments, there is every warranty 

 for stating that the use of the superphosphates will result in larger 

 yields to an extent justifying aji undoubted claim to first considera- 

 tion. With an improvement in composition on the part of Thomas 

 phosphate, equalling the figures of the earlier analyses carried out in 

 this laboratory, the present differences so largely in favor of super- 

 phosphate will naturally be considerably reduced. The composition 

 of the two fertilizers used in the experiments during the two years is 

 given below. Earlier analyses than these revealed a quality of 

 Thomas phosphate superior to the best here shown, reaching as high 

 as 20 per cent, of phosphoric acid. 



