49 



Those farmers who are more accustomed to the word am- 

 monia tha-n to the term nitrogen, can change the figures for 

 nitrogen into their ammonia equivalents by multiplying by 



Unless explained, the term "profit from fertilizers" as 

 used in the following tables, might be misunderstood. 



Profit or losis, as there used, is simply the difference be- 

 tween the value of the increase attributed to the fertilizer 

 and the cost of the latter. To make this more exact, the 

 careful reader may subtract from the apparent profit cer- 

 tain small items, which, because variable, could not be in- 

 corporated in the table — for example, cost of applying fer- 

 tilizers and cost of picking and ginning the increase. 



Again, the actual profit per acre from cotton culture may 

 be greater or smaller than the ''profit from fertilizer.'* 

 When on the unfertilized plot cotton is produced at a loss 

 of say |3 per acre, and when the tables show, say $10 as 

 the profit from a certain fertilizer mixture, a part of this 

 profit must go towards offsetting the loss that would have 

 occurred without fertilizers, leaving the farmer in this case 

 only $7 in actual profit, although the fertilizer may have 

 been beneficial to the -extent of $10 over and above its cost. 

 On the other hand, when cotton is produced at a profit on 

 unfertilized land, and when fertllizens also show a profit, 

 the sum of these two items is very nearly the farmer's act- 

 ual profit. 1 



In determining the increase over the unfertilized plots,, 

 the yield of the fertilized plots, Nos. 4, 5, G and 7, is com- 

 pared with both unfertilized plots lying on either side, giv- 

 ing to each unfertilized plot a weight inversely proportional 

 to its distance from the plot under comparison. This meth- 

 od of comparison tends to compensate for variations in the 

 fertility of the several plots. 



It should, be remembered that seasons, ais well as soils, 

 determine the effects of fertilizers, so that to be absolutely 



