11 



A conspicuous fact observable in the above table is that 

 the figures here are smaller than the corresponding figures 

 in the first table. This was to be expected. The plant at 

 this stage of growth is nearing maturity, and the three impor- 

 tant constituents are being rapidly stored up in the seed. 



Studying the table in detail, we find that in the Drake 

 field the lowest percentages of potash are in 5 and 7, where 

 there was no potash fertilization, while the highest is in 9, 

 where there is complete fertilization and where there is, also, 

 the highest yield of cotton. As we shall see a little later, 

 the average of the percentages of potash in plots in the field 

 which have potash fertilization, is about the same as that in 

 the richer soil of the garden. Singularly enough we have 

 in 9 one of the lowest percentages of nitrogen, but the other 

 two nitrogen-fertilized plots bring up the average, and with 

 this constituent, as with potash, we have an increase of per- 

 centages due to fertilization. We must observe, however, 

 the small variation between the maximum and minimum in 

 this column. 



Coming now to the garden plot we find that the average 

 efifect of potash fertilization is to increase the percentages of 

 potash, while, on the other hand, nitrogen fertilization does not 

 seem to have a like effect on the percentages of nitrogen. 

 This would seem to indicate that the garden soil contains a 

 deficiency of potash, but a sufficiency of nitrogen. 



The results on phosphoric acid are worthy of special atten- 

 tion. With a single exception the percentages of this con- 

 stituent in the Drake field in the boiling stage, are decidedly 

 lower than the corresponding ones in the flowering stage, 

 while no such marked change is observable in the garden 

 percentages. It would seem, therefore, that there is a de- 

 ficiency of available phosphoric acid in the Drake field, 

 which was not shown by the analysis at the earlier stage, 

 and further, that there is no such deficiency in the garden 

 soil. The exceptional case referred to is in 5, where the 



