352 



EXPEPJMENTAL STATIONS — REPORT FOR 1880. 



Dissolved Phosphates, Straw. 



A glance at the first column of these tables shows that the 

 effect of dissolving the pliosphatic manures is to increase the 

 yield of grain 251 lbs. per acre, or about 18 per cent., and that 

 of straw about 3^ cwts., or about 12 per cent. The other 

 columns show that it has no material influence upon the 

 percentage composition of the crop. The increase is shared 

 very equally by all the constituents of the barley, or in other 

 words, it is the quantity of the crop that is increased, the qiicdity 

 is apparently unaffected. A comparison of the individual plots 

 shows considerable variations where undissolved phosphates are 

 used, and this is no doubt due in great measure to the different 

 degrees of fineness of the various manures. It is evidently not 

 fair to compare the immediate effects of undissolved phosphates 

 of various degrees of fineness, and if these are to be more largely 

 made use of in future, it will be necessary to establish some stan- 

 dard of fineness of division by which to estimate their value as 

 manures for the crop to which they are immediately applied. 

 There is no doubt that in the above experiment, plot 5 suffers by 

 comparison with the other plots on account of the difficulty of 

 reducing bone dust, unless specially prepared, to the degree of 

 fineness attainable with the other forms of phosphate. In the 

 case of dissolved phosphates there is no such difficulty. The 

 process of dissolving secures a fineness of division which 

 even the finest grinding cannot imitate, and the result is 

 that the plots manured with dissolved phosphates are much 

 more even in their character, and indeed may be considered 

 almost on an equality. The cheapest form of superphosphate 

 seems to be quite as good as the dearest form of dissolved bones. 



