Decembku 11, UI03.] 



SCIENCE. 



59 



knows thiit dutioicuoy of inoistinv or heat, or 

 imperfect cultivation, as well as the improper 

 manner of application of fertilizers, may 

 render them wholly inctfective. We have also 

 long known that soluble fertilizers soon be- 

 come insoluble (but not necessarily unavail- 

 able) in the soil, in a manner fairly well un- 

 derstood, and that hence they can not long 

 influence the watery soil solution to which 

 Whitney pins his faith. But since the same 

 conditions influence the unfertilized soils to 

 even a greater degree, manifestly because of 

 the slower and less vigorous development of 

 the plants, it is not easy to see what special 

 corroboration Whitney's hypothesis can derive 

 therefrom. He calmly discards, as having 

 been made under ' abnormal conditions,' the 

 elaborate and conclusive experiments made 

 by the best observers in pot cult\irc, in which 

 the jihysieal factors were so controlled as to 

 eliminate them from the problem of the action 

 of special fertilizers; and we are told that 

 ' very little efTect is obtained in field culture 

 in attempts to increase the value of crops 

 showing inferior growth, by the application 

 of fertilizers.' A trip through the malodorous 

 turnip fields of the Low Countries or of 

 Switzerland in autumn would convince even 

 the Bureau that the thrifty inhabitants know- 

 that when a fertilizer is made to reach the 

 feeding roots its action is invariably most 

 strikingly beneficial. That a top dressing of 

 insoluble fertilizers on a growing crop can do 

 but little good needs no discussion; and it 

 is but too true that a great deal of the fertil- 

 izers used in the arid region remains wholly 

 ineffective for a long time becau.se of the deep 

 range of the feeding roots and the shallow 

 application of insoluble fertilizers. 



In the cla-ssic water-culture experiments of 

 Birner and Lucanus, quoted in the bulletin 

 (p. 15), the well water was supplied continu- 

 ously and in indefinite amounts. It is thus no 

 wonder that the results were so good, for at no 

 time was there a lack of plant food supply, 

 nor would such changes as would injuriously 

 affect the growth occur. But for these fre- 

 luent renewals of the water the result would 

 doubtless have been very different, if only as a 

 I'onsequence of changes in the reaction of the 



solution. It is singular tiiat this important 

 point is not even casually mentioned in the 

 bulletin with respect to the soil solutions. 

 The deleterious effects of soil acidity upon 

 most culture plants, long known in general, 

 has been well and thoroughly investigated by 

 II. J. Wheeler.* Yet neither in the tables nor 

 in the text of this bulletin do we find any 

 evidence that this point has had any attention 

 with respect to its possible bearings on the 

 differences in production on what are held by 

 the bureau to be identical soil areas. We are 

 not informed whether the large amounts of 

 lime present in some of these solutions were 

 sulphate or carbonate; yet the importance of 

 this difference is enormous, as is well shown 

 by the contrast between the natural vegetation 

 as well as the cultural value of gypseous as 

 against limestone lands, which are everywhere 

 among the most productive. An excellent 

 illustration of what this omission may mean 

 exists on the Gulf Coast of Mississii)pi, 

 where (as I have shown in the ' Report on 

 Cotton Culture,' Tenth Census, Vol. 5, p. 69) 

 the soil of the infertile ' sand hammocks ' dif- 

 fers from the highly and lastingly productive 

 soil of the ' shell hannnocks ' almost alone in 

 the proportion of lime (calcic carbonate) and 

 phosphoric acid present, and in having an 

 acid reaction; the percentages of plant food 

 being very low in both, and both equally of 

 great depth. This observation, together with 

 others, led me very early (ISfiO) to the con- 

 clusion that mere percentages of plant food 

 were not in all eases proper criteria of soil fer- 

 tility; and also to the enunciation of the state- 

 ment wliich I have repeated many times in 

 both my teaching and my publications, to wit : 

 ' Wliile all fresh soils of high plant food per- 

 centages are highly productive under all but 

 very extreme physical conditions, the reverse is 

 by no means true; since soils with low percent- 

 ages may be highly productive if the relative 

 proportions of the several ingredients be good, 

 and the soil mass deep.' I have for some .years 

 carried on an investigation to detennine the 

 limits of dilution within which plants will do 

 equally well in soils of high fertility (and 

 plant food percentages) when these are diluted 

 • r!p|H)rts of the KlioUe Island E.\pt. Sia. 



