THE ORGANIC CONSTITUENTS OF SOILS. 1 



The reports on the various phases of soil studies by the investi- 

 gators who have preceded me in this symposium must have impressed 

 you with the fact that the subject of soil fertility and infertility is 

 by no means a simple matter of arithmetic, which involves only a few 

 of the mineral constituents of the soil. It must also have become 

 clear to you that the problem of soil fertility or infertility has not 

 been solved by the application of these simple arithmetical means 

 based on soil analysis or by the crop statistics accumulated in the 

 years which have elapsed since Liebig first announced his views on 

 soil fertility, which gamed for him for all time the title of "Father of 

 Agricultural Chemistry." It is particularly gratifying to me, since 

 I am to talk to you to-day on the subject of the organic constituents 

 of soils, their chemical nature and other properties, that Liebig is 

 also known as the "Father of Organic Chemistry." To what tre- 

 mendous proportions and significance in the world's industries and 

 science this child of his (Organic Chemistry) has grown is familiar 

 to all of you, and I assure you that Liebig, were he to return to-day, 

 would be proud of its parentage. But I fear he would be displeased 

 with his other child, as having made so little progress in the inter- 

 vening years, although he started it in life strong and virile and full 

 of promise. Up to a few years ago agriculture had not shared in the 

 great impulses which modern science has given to other arts and 

 industries, and the domination of the mineral-requirement theory 

 proposed in the first half of the last century and accepted without 

 adequate proof of its validity is largely responsible for the lack of 

 development in agriculture, commensurate with the enormous strides 

 of other arts and industries under the guidance of modern scientific 

 thought and research. But a new era of scientific inquiry is at hand, 

 and all phases of scientific endeavor are being applied to the solution 

 of the problems connected with soil fertility and infertility lines of 

 endeavor which were not even known in Liebig's time, but which 

 to-day are well-recognized factors in soil fertility. I refer to the 

 study of soil bacteria, soil fungi, soil protozoa, and other micro- 

 organisms, and all the biochemical functions of these, as well as of 



i Address given at the Symposium on Soils at the Washington meeting of the American Association for 

 the Advancement of Science. The detailed results of the investigations mentioned in this address can be 

 found in Bureau of Soils bulletins Nos. 40, 47, 53, 56, 70, 73, 74, 80, 83,.86, 87, 88, 89 90. 



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