THE ANALYSIS OF VIRGIN SOILS. 



343 



writer for his work; and it, together with the acid of 1.115 

 density, is the basis of all the results given in this volume, ex- 

 cept where otherwise stated. There appeared to him to be 

 no good reason for the acceptance of the arbitrary method of 

 soil-extraction suggested by Kedzie and since adopted by the 

 Association of Official Agricultural Chemists; the more as to 

 do so would throw out of comparison all the previous work 

 done by Owen, Peter, and himself and his pupils, which had 

 already been definitely correlated with the natural conditions 

 and with cultural experience. 1 



Virgin Soils with High Plant-food Percentages are Always 

 Productive. In strong contrast to the contradictory evidence 

 deduced from the analysis, by any method, of cultivated soils 

 when compared with cultural experience, it seems to be gener- 

 ally true that virgin soils showing liigh percentages of plant- 

 food as ascertained by extraction with strong acids (such as 

 hydrochloric, nitric, etc.), invariably prove highly productive: 

 provided only that extreme physical characters do not interfere 

 with normal plant growth, as is sometimes the case with heavy 

 clays, or very coarse sandy lands. To this rule no exception 

 has thus far been found. The composition of some represen- 

 tative soils falling within this category is given in the annexed 

 table, which at the same time conveys some idea of the propor- 

 tion of acid-soluble ingredients usually found in the best class 

 of natural soils. 



Discussion of Table. It will be noted in this table that while 

 the total of the matters soluble in acids (inclusive of silica) 

 ranges from a little below 50 to over 77 per cent, the total of 

 directly important mineral plant-food ingredients (potash, 

 lime, magnesia and phosphoric acid), constitute in moderately 

 calcareous soils only from about 2.5 to somewhat over four 

 per cent of the whole. Yet if all these were in available form, 

 the supply would be abundant for many hundreds and even 



1 While regretting to thus " secede " from the fellowship of his colleagues, the 

 writer cannot but regret equally their voluntary decision to do over again, or 

 lightly reject, all that had been done before in correlating soil-composition and 

 plant-growth. He still thinks that it is idle to expect any unification, national ot 

 international, of methods of soil analysis based upon purely arbitrary prescriptions, 

 unless previously shown to be definitely correlated with natural and cultural con- 

 ditions j as is measurably the case with Dyer's method. 



