16 



phoric acid. The humus phosphoric acid, all of which is 

 believed to be readily available to the plant, is 75 % higher 

 in the garden than in the field. In total available inorganic 

 matter — that which dissolves out Avith the humus — the 

 garden soil is 46 "o richer than the field soil. 



It will thus be seen that the garden soil in the main 

 is richer in the important inorganic constituents than the oth- 

 er soil; but it is believed that its superior fertility is chiefly 

 due to its larger proportion of organic matter. In total or- 

 ganic matter it is 41.6 ,"o ; in humus, 48.8 %; and in total 

 nitrogen, 24.8 % richer than the other. 



CONCLUSIONS. 



It is not safe to base conclusions on a single series of ex- 

 periments. Further investigations may make it necessary 

 to alter some of the opinions suggested in this paper, and 

 some of these conclusions here may have to be withdrawn, 

 but it is believed that the broadest conservatism will sanc- 

 tion the following conclusions from the results herein pre- 

 sented : 



1. That the composition of the cotton plant in respect 

 to potash, phosphoric acid, and nitrogen, is subject to deci- 

 ded variations under varying conditions. 



2. That the nature of the soil exerts a considerable in- 

 fluence on the composition of the plant, a rich soil giving 

 higher percentages of the three important constituents than 

 a poor soil. 



3. By fertilizing with either of the three constituents in 

 soils not already containing a sufficiency of the same, it is 

 possible to increase the percentage of that constituent in the 

 cotton plant which is grown on such soil. 



4. That humus in the soil is of great value, not only in 

 supplying organic constituents, but, also, in holding inor- 

 ganic constituents in most available conditions. 



It is not claimed that the results herein described demon- 

 siraie the utility of this method as a means of determining 

 soil requirements for cotton, but it is claimed that they are 

 highly suggestive. If the normal composition of the healthy, 

 thrifty plant under given soil conditions be known, we be- 

 lieve it possible to determine when a deficiency of any of 

 the three constituents exists in a given soil. Systematic 

 determinations, therefore, of the composition of the cotton 

 plant under normal healthy conditions, together with deter- 

 minations of the chemical composition and the physical 

 properties of the producing soil, will furnish a basis, it is 

 believed, for the establishment of a plan of investigation 

 which will prove of great value to the agricultural interests 

 of the South. 



