328 



Bulletin 179. 



* For the meaning of these abbreviations and the rate at which the fertilizers were applied 

 see page 317. 



On studying tliis table it is plainly seen that available phosphoric 

 acid in the soil was at a minimum, since the yield was best on all the 

 plats which received phosphate, whether alone or mixed with one or 

 both of the other plant-foods. It appears further that neither pot- 

 ash nor nitrogen with phosphate added much to the crop over and 

 above the yield with phosphate alone ; therefore it would be poor 

 policy to use a complete fertilizer for corn on this field. The 

 experiments of 1S07 and 1898 also showed that phosphoric acid was 

 the one plant-food that was deficient in that soil. 



On comparing the estimated yields per acre from each cutting, 

 we see that in every case there was a decided increase in the total 

 crop during the last week of growth and that these increases per 

 ton were quite uniform. This shows that the estimated yields per 

 acre w^hen calculated either from one square rod or from eight square 

 rods are very nearly alike and that correct results can be obtained 

 by measuring the crop of a part only of each plat. 



The value of stable manure as a fertilizer is very distinctly shown 

 in the results of this series of experiments, the increase over the 

 yield on the blank plat being more than three times the increase 

 given by any other fertilizer. Although the quantity of the manure 

 applied contained less available nitrogen compounds, potash and 

 phosphate than was contained in the commercial fertilizers used, it 



