3 66 INVESTIGATION BY CULTURE EXPERIMENTS ^ 



America as well; namely, that practically no provision has been 

 made for maintaining any adequate supply of decaying organic 

 matter in the soil, in consequence of which, in the author's opin- 

 ion, the soil itself becomes practically inactive, and, if satisfactory 

 crops are to be grown, every essential element of plant food must 

 be supplied artificially in readily available form. 



According to well-established and universally accepted physical 

 laws, a solution is always saturated so long as there is contact 

 and equilibrium between the solution and the undissolved sub- 

 stance ; but, in the author's opinion, this law of solution does not 

 apply to the soil mass as a whole, for equilibrium is never estab- 

 lished in the soil mass as a whole. In the unlimited and unquali- 

 fied application of this entirely correct solution theory, we might 

 say that the peaty swamp lands of Illinois have direct capillary 

 connection with the potassium mines of Germany ; but the fact is, 

 that, where 200 pounds of potassium sulfate per acre have been 

 applied to that peaty swamp land with a resultant yield of more 

 than 50 bushels of corn per acre, the crop on the untreated ad- 

 joining land, separated only by a half-rod division strip, receives 

 absolutely no benefit because of any capillary connection, and 

 yields less than 5 bushels of corn per acre, even where the experi- 

 ment is continued year after year. 



Even regarding the Rothamsted permanent grass plots, which 

 are separated only by a line, which vary in soluble fertilizers re- 

 ceived from none to a ton per acre per annum, in average yield 

 from one to three tons of hay per acre, and in herbage from 

 strictly nonleguminous to fifty per cent of legume plants, the state- 

 ment is made by Director Hall that, " although the treatment has 

 been repeated now for fifty-two years, the dividing line between 

 the two plots remains perfectly sharp, and the rank herbage pro- 

 duced by the excess of nitrogenous fertilizer on one side does not 

 stray six inches over the boundary." 



Unquestionably the film of water surrounding a soil grain be- 

 comes a saturated solution of all the minerals exposed on the 

 surface of that individual particle, but this solution may be of 

 different composition from each of the other films surrounding 

 the other billion or more soil grains which may exist in the same 

 cubic inch of soil, of which, perhaps, only one in a thousand con- 



