No. 6. DEPARTMENT OF AGRICULTURE. S63 



01 wheat than the noticing plots, which would seem to show that the 

 feeding habit of wheat is very different from corn and that it par- 

 ticularly benefitted by the addition of phosphoric acid. 



Soluble PkoxphoriG Acid (Nos 1, % 3). The figures in Table 19 show 

 that all the other forms of phosphoric acid gave higher total yields 

 in five years than the soluble phosphoric acid, except oh the plots 

 where rye was turned under. The slightly higher total yield in the 

 case of the rye turned under is accounted for in the corn crops, and 

 is probably due to the rj-e decomposing slowly and causing the 

 soil to dry out easily, have a poor physical condition and thus suffer 

 from drought. Soluble phosphoric acid seems to be particularly 

 beneficial to wheat where it gave the highest average yield. The 

 probable failure of soluble phosphoric acid to give good yields on 

 corn has been discussed under the nothing plots. 



A comparison of the different sources of soluble phosphoric acid 

 shows the total yield to stand in favor of the most concentrated 

 fertilizer, or in the order of the plot Nos. 1, 2, 3. The wheat yield 

 was in favor of the dissolved bone black, and hay was best on the 

 dissolved South Carolina rock plots. This was probably due to 

 the action of the sulphate of lime in the dissolved goods, liberating 

 and forming available combinations with the potash in the soil. 



Reverted Phosphoric Acid (Nos. 4 and 6). Reverted phosphoric 

 acid gave better total yields for the five crops and better average 

 yields in corn and hay, than soluble phosphoric acid, though not 

 quite so large a yield of wheat. This would seem to confirm the 

 popular idea that reverted phosphoric acid has as great an agri- 

 cultural value as soluble phosphoric acid. A comparison of reverted 

 phosphate of lime and reverted phosphate of iron and alumina show 

 in every instance with every crop to be in favor of the reverted phos- 

 phate of iron and alumina. 



Insoluble Phosphoric Acid (Nos. 7, 8, 9, 11, 12, 13, 14, 16, 17, IS, 19, 

 21 and 22). An examination of Table 19 shov^-s the average yield 

 of five insoluble phosphoric acid plots (Nos. 7, <S. 9, 11 and 12) to 

 have produced considerably more grain than either the soluble or 

 reverted forms of phosphoric acid ,but the amount of fodder was 

 slightly in favor of both the latter. The total product (grain plus 

 the fodder) was more on the insoluble than on the soluble phosphoric 

 acid plots, and within forty-two pounds as much as the reverted phos- 

 phoric acid. The value of these results is still further advanced 

 when it is considered that the price of the insoluble phosphoric acid 

 was only about one-half as much as that obtained in the soluble and 

 reverted forms. The above comparisons include only Plots 1 to 12, 

 as these were treated uniformly with respect to turning under crim- 

 son clover, green. 



