Tub Bulletin. 



27 



that are very striking. Even after making due allowances for the 

 heavier application of phosphoric acid, the large average gain of 

 13.1 hushels per acre for this element as compared with l.G for 

 nitrogen and .8 for potash certainly confirms the conclusion that 

 phosphoric acid is the controlling constituent of plant food for the 

 Toxaway loam. The relative yield of oats on these plats is illustrated 

 on the cover of this bulletin. 



PORTER S LOAM. 



Field "B' is located on representative Porter's loam. It consists 

 of 19 plats, with the same plan of treatment as field "A" on the 

 Toxaway loam. The same materials were used and the relative 

 applications for the plats have been the same. However, the normal 

 ap]ilieation was at the rate of 300 pounds per acre for both years. 



The plats included in table 5 correspond to those of field ''A" in 

 table 3. 



We find that phosphoric acid again gives ns the largest increase in 

 grain, but the average gain is greater for nitrogen. There is little 

 difference in the average gain in gi'ain for nitrogen, potash or lime. 

 However, though the nitrogen is credited with a gain of 442 pounds 

 of stover per acre, both potash and lime failed to increase the stover 

 over no fertilizer. 



