No. 1, May, 1921] SOIL SCIENCE 99 



SOIL SCIENCE 



J. J. Skinxer, Editor 

 F, M. ScHERTZ, Assistan' Editor 



(See also in this issue Entries 9, 13, 14, 20, 24, 25, 28, 34, 92, 93, 97, 108, 557, 604) 



675. Anonymous. Fertilizers and parasiticides. [Rev. of: Collins, S. H. Cliemical 

 fertilizers and parasiticides, xii + 273 -p. Bailliere, Tindall, and Cox: London, 1920.] 

 Nature 106: 206-207. 1920. — Review refers to fertilizers only. — 0. A. Stevens. 



676. Seals, Colonzo C. Soil survey of Cass County, Indiana. Proc. Indiana Acad. Sci. 

 1918: 186-204. 1920.— The upland soils are of the Clyde, Miami, and Dunk'rk type. Muck 

 also is present. The principal crops are corn, wheat, oats, clover, timothy, and potatoes. 

 The paper is largely descriptive. — F. M. Schertz. 



677. C ARR, R. H., AND Leroy Hoffman. The relation of nitrogen, phosphorus and organic 

 matter to corn yield in Elkhart County, Indiana. Proc. Indiana Acad. Sci. 1918: 160-165. 

 Soil map. 1920. — About 50 per cent of the soils of this county are of the Miami loam and 

 Miami sandy loam types and about 27 per cent ate of the Plainfield sandy loam type. These 

 soils are low in organic matter and 51 per cent are acid. Crop yield bears a close relation to 

 the organic matter present and this in turn is closely associated with the amounts of nitrogen 

 and phosphoric acid present. Three samples show that good crops are not always obtained 

 from soil with the requisite plant food content. The difference in yield between the 0.2 per 

 cent and the 8-10 per cent organic matter in soils averages 25.6 bushels. In average field 

 conditions for each increase of 2672 lbs. of organic matter, 71.6 lbs. of nitrogen, and 35.7 lbs. 

 of phosphoric acid per acre (2,000,000 lbs.) there is an increase of 1 bushel of corn. — F. M. 

 Schertz. 



678. Carr, R. H., and V. R. Phares. Analyses of one hundred soils in Allen County, 

 Indiana. Proc. Indiana Acad. Sci. 1918: 151-159. Soil map, pi. 1-3. 1920.— The soils are 

 of glacial origin, 70 per cent belonging to the Miami series and 18.5 per cent to the 

 Clyde series. Determinations of the volatile organic matter, phosphoric acid, and nitrogen 

 were made. In organic matter, 11 per cent of the soils had less than 4 per cent; 45 per cent 

 of the soils ranged from 4 to 7 per cent; 37 per cent from 7 to 15 per cent; and 6 per cent were 

 above 15 per cent. Each per cent increase in organic matter carried with it an increase of 

 519 lbs. of nitrogen and 72 lbs. of phosphoric acid per acre. Charts show that nitrogen has 

 more influence on high corn j'ields than has phosphoric acid. Fifty-five per cent of the soils 

 were acid to litmus, a condition causing "clover sickness." — F. M. Schertz. 



679. Hoffmann. Diingungsversuche mit neuzeitlichen Stickstoffsalzen im Emtejahr 

 1920. [Fertilizer experiments with new nitrogen salts in 1920.] Mitteil. Deutsch. Landw. Ges. 

 36: 26. 1921. — The author brings together in tabular form the records of cooperative fer- 

 tilizer experiments with various salts of nitrogen. — A. J. Pieters. 



680. NoYES, H. A., AND G. L. Grounds. Number of colonies for a satisfactory soil plate. 

 Proc. Indiana Acad. Sci. 1918: 93-101. PL 1-2, fig. 1-7. 1920.— Tests have shown that 30 

 colonies of bacteria is the optimum number for a petri dish 100 mm. in diameter. Plates 

 carrying between 10 and 100 colonies are satisfactory for computing bacterial counts. 

 F. M. Schertz. 



681. NoYES, H. A., Edwin Voigt, and J. D. Luckett. The length of time to incubate 

 petri plates. Proc. Indiana Acad. Sci. 1918: 102-109. 1920.— Counts made after 10 days' 

 incubation at 20°C. from bacterial dilutions of soil gave reliable results for the bacterial con- 

 tent of the soil, provided the number of bacteria present was small enough to allow all bac- 

 teria to develop into colonies. The rapidity with which bacteria develop into colonies varies 

 with the soil and is influenced by soil temperature, moisture, and aeration. — F. M. Schertz. 



