60 



The Bulletin 



The results certainly indicate that phosphoric acid and nitrogen are 

 the fertilizing constituents first needed by this soil. Phosphoric acid 

 alone gave an increase of 13.5 bushels corn and 745 pounds of corn 

 stover, 11.8 bushels wheat and 355 pounds of seed cotton; while nitrogen 

 alone yielded an increase of 9.6 bushels of corn and 345 pounds of corn 

 stover 1.8 bushels of wheat, and minus 50 pounds of seed cotton per acre. 

 Potash alone gave an average increase per acre of 5.3 bushels of corn 

 and 700 pounds of corn stover, 0.5 bushels of wheat, and 305 pounds of 

 seed cotton. Lime alone as well as in combination with the other plant 

 food constituents, like potash, made a poor showing. The results show 

 that for these crops at the present time neither potash, nor lime can 

 be used profitably on this soil in its present state. 



The average gain for four nitrogen plats, when used alone and in 

 combinations, are 8.8 bushels of corn and 430 pounds of stover, 7.2 

 bushels of wheat, and 8Q pounds of seed cotton. 



The gain for phosphoric acid with corn was about the same as tlie 

 average gain for nitrogen, but the gains on an average were about 49 



Fig. VII. Wheat grown at the Iredell Farm and fertilized with nitrogen, phosphoric acid 

 and potasla. Note marked difference in growth resulting from the addition of phos- 

 phoric acid, by contrasting the wheat in this with that shown in Fig. VI. 



per cent greater with wheat and 230 per cent greater with cotton from 

 the phosphoric acid applications than from the nitrogen applications. 

 The average of the four cases where potash forms the only difference in 

 treatment shows a decrease of 1.9 bushels of com and 1.3 bushels of 

 wheat and an increase of 50 pounds of stover and 119 pounds of seed 

 cotton. It will be observed from the results given in the last column of 

 the table that the greatest value of increased yields over the unferti- 

 lized plats was secured from plat 6, which received an application con- 

 sisting of acid phosphate and dried blood, but had no carrier of potash 

 applied. The increased yields from plats 11 and 10 over the unferti- 

 lized plat were respectively next highest in value. The marked bene^ 

 fits resulting from applications of carriers of phosphoric acid and nitro- 



