December U, 1903.] 



SCIENCE. 



757 



of Soils, while still inaintainiiifj the prefer- 

 ential claim for the physical properties of the 

 soil, at least admits the importance of the 

 functions of plant food; but claims that fertil- 

 ization is unnecessary because the supply will 

 be ' indefinitely maintained.' He in fact takes 

 us back to the times of Jethro Tull and the 

 Louis Weedon system of culture, which also 

 presupposed the indefinite duration of pro- 

 ductiveness; but signally failed to realize it 

 when the test of even as much as twelve years 

 came to be applied. How can Whitney recon- 

 cile this predicted indefinite productiveness 

 with the actual facts well known to every 

 farmer, good and bad, who has ever taken fresh 

 land into cultivation, and when pricing it is 

 perfectly aware that after a period ranging 

 from three years, e. g., on the long-leaf pine 

 lands of Mississippi to thirty or more years in 

 the black prairies, he must needs resort to fer- 

 tilization if he wants a paying crop; while in 

 the Yazoo clay lands and the alluvial soil of 

 the Ilouma country, hardly a diminution of 

 production has occurred even yet? If, in- 

 deed, the soil solution is of the same composi- 

 tion in all these lands, then the common-sense 

 conclusion is, obviously, that if the soil solu- 

 tion is the sole vehicle of plant nourishment, 

 it must be supplied more quickly and contin- 

 uously in the * rich ' than in the ' poor ' soils. 

 Certainly, considering that both rich and poor 

 soils are represented in the entire gamut of 

 physical texture, it is impossible to conceive 

 that such changes in texture as would be 

 brought about by poor cultivation should not 

 occur in both. Yet the rich soils — those 

 shown by the despised chemical analysis with 

 strong acids to contain abundance of plant 

 food, continue to produce abundantly, while 

 the poor lands ' give out.' Hence, admitting 

 for argument's sake that the soil solutions are 

 really of the same chemical composition, it 

 is clearly not the physical texture alone, or 

 chiefly, that can account for these differences. 

 Whitney states in this connection (p. 51) 

 that I have 'called attention to an apijarent 

 exception to this rule (that production is 

 sensibly proportionate to the water supply) 

 in heavy adobe (heavy clay) and sandy lands 

 in California, which bear equally good crops 



of wheat.' It happens that this ' exception ' 

 holds good throughout the somewhat extensive 

 arid region of the United States ; and my ex- 

 planation is not only, or mainly, that the roots 

 go deeper, but that in the arid region, sandy 

 soils are as a rule quite as rich in plant food 

 (again by chemical analysis of the rejected 

 sort) as the clay soils. Hence the abundant 

 and lasting production of the arid sandy lands 

 (even drifting sands) when irrigated. 



Whitney's argument that even the rich arid 

 soils can not yield more than the maximum 

 crops of the humid region can hardly be taken 

 seriously. 



It is a striking fact that in the entire bul- 

 letin only a single full soil analysis (i. e., one 

 made with strong acids) is quoted. There is 

 a table giving the results of determinations 

 of available plant food, determined by the 

 official method, alongside of the distilled water 

 extract ; and it is apjjarent that the two differ 

 widely. But there is no definite agreement 

 among soil chemists as to the ' available ' de- 

 terminations, whether as to value or method; 

 tiie matter is still in the tentative stage, and 

 I wholly dissent from the ' official prescrip- 

 tion.' The table in question proves nothing. 

 But it would have been instructive, so long 

 as Whitney wishes to disprove the value of 

 soil analysis as usually made, to have at least 

 some of the soil classes he adduces- as proofs, 

 analyzed by the usual methods ; if only in order 

 to show that these soil types — the Cecil clay, 

 the Sassafras loam, !Jforfolk sand, etc., are 

 really, as alleged by him, the same soils over 

 the area assigned to them. How have these 

 soils been identified in the mapping? We are 

 informed (p. 8) that ' the classification of soils 

 in the surveys made by this bureau is based 

 mainly on physical differences, apparent to a 

 trained observer.' It is apparent from the 

 annual reports that the mineralogical and 

 geological data which are elsewhere considered 

 as essential to a definite characterization of a 

 soil, and which certainly are to be counted 

 among the physical characteristics, are in most 

 cases wholly ignored. Instead, we have local 

 names by the thousand, conveying no meaning 

 whatever to those not acquainted with the 

 localities; since nothing but a scantily inter- 



