814 EXPERIMENT STATION RECORD. 



quality is entirely due to this cause. Attention is also called to the fact that 

 stony soils are favorable to the ri])ening and quality of cereals. 



Some factors influencing the percentages of mineral plant foods contained 

 in soils, O. D. von Engeln {Anier. Jour. Sci., Ji. ser., 32 (1911), No. 191, pp. 

 350-358; abs. in Chem. Abs., 6 (1912), No. 3, p. Ji02).— In this article an attempt 

 is made to correlate selected soil analyses with soil history " in order to ascer- 

 tain if any correspondence exists between the present chemical composition 

 of soils and the formative processes involved in their production." 



The general conclusion reached is that there are not sufficient reliable data 

 on the chemical composition of soils in the United States to warrant broad 

 generalizations regarding the effects of varying amounts of mineral plant food 

 on soil fertility, and that further systematic investigation along this line is 

 needed. 



The results, however, " indicate a relationship between chemical composition 

 and the geologic-physiographic conditions of soil origin and state." For ex- 

 ample, residual soils are apparently notably deficient in plant food (phosphoric 

 acid, potash, and lime) as compared with their parent rocks. Soils of the 

 younger glaciatiou uniformly show more plant food (phosphoric acid and 

 potash) than those of the older glaciatiou, the residual soils being intermediate 

 in this respect. The author is of the opinion that soil classification should 

 follow physiographic principles and that " the names of soil series might well 

 correlate with recognized physiographic and geologic formations in the United 

 States." 



A brief study of the phosphorus associated with the matiere noire, J. 

 Stewart (Abs. in Science, n. ser., 35 (1912), No. 897, p. 319). — In this paper, 

 which was presented at the Washington meeting of the American Chemical 

 Society in 1911, the author "attempts to answer the question: Is the phos- 

 phorus in the matiere noire organic or inorganic? 



" Treatment of the soil with ammonium hydroxid fails to extract any phos- 

 phorus. Partial removal of acid-soluble phosphorus and complete removal of 

 acid-soluble phosphorus, followed in each case with ammonium hydroxid ex- 

 traction, gives ammoniacal solutions with practically identical phosphorus con- 

 tent, viz, approximately 0.0103 per cent on soil. The conclusion is that all the 

 phosphorus associated with the matiere noire is organically combined. Prac- 

 tically all the iron and aluminum present in the matiere noire are organic. 

 Hydrolysis takes place during extraction with alkali and a large part of the 

 phosphorus and some iron and aluminum are converted into inorganic forms. 



" Several precipitating reagents for separating inorganic phosphorus from 

 organic were tried, but results were unsatisfactory." 



Nucleic acids in soils, E. C. Shorey (Abs. in Science, n. ser., 35 (1912), No. 

 897, p. 390). — This is an abstract of a paper presented at the Washington 

 meeting of the American Chemical Society in 1911. 



It is stated that " nucleic acids have been obtained from soils by extraction 

 with dilute sodium hydroxid, neutralizing and concentrating under reduced pres- 

 sure, acidifying with acetic acid and addition of several volumes of alcohol, as 

 a light-colored amorphous body, which on hydrolysis gave pentose sugars, purin 

 bases, pyrimidin compounds, levulinic acid, and phosphoric acid. Xanthin and 

 hypoxanthin were identified among the purin bases and cytosin among the 

 pyrimidin compounds." 



The action of nucleic acid and its decomposition product on soils and 

 plants, O. ScHREiNEE and J. J. Skinner (Abs. in Science, n. ser., 35 (1912), No. 

 897, p. 390). — In a paper presented at the Washington meeting of the American 

 Chemical Society in 1911, of which this is an abstract, it is stated that " nucleic 

 acid as well as some of its decomposition products occur in soils, and the effect 



