No. 4, February, 1922] SOIL SCIENCE 307 



bushels corn, 39.3 bushels oats, and 20.8 bushels wheat. The total yield of all products for 

 this plot was 15,011 pounds as against 2,196 pounds for the rotations average yield on the 

 5 unfertilized plots. Phosphoric acid has given the greatest yield of grain, clover hay, and 

 Kentucky blue grass. Potash has given the next greatest yield of grain and clover haj' while 

 nitrogen has given a greater yield of blue grass than potash. Acid phosphate has been 5 

 times as effective as rock phosphate, on the basis of equal amounts of phosphoric acid, in 

 bringing about increased yields. — On Volusia soil the results of 2 years' experiments show 

 that lime is indispensible in crop improvement. Six tons of manure with lime gave an in- 

 crease over manure alone of 1250 pounds hay, 10.8 bushels corn, and 4,378 pounds pasture 

 grasses. Manure reinforced with acid phosphate on limed soil gave an increase over manure 

 used alone of 1350 pounds hay, 20.3 bushels corn and 0,438 pounds pasture grasses. — On the 

 Westmoreland soil the most striking result for the 2 years is to be seen in the comparisons 

 between acid phosphate and rock phosphate. On 4 plots on which the 2 sources of phosphoric 

 acid were compared, acid phosphate was 183 per cent more effective than the rock phosphate 

 for the proportions used in the experiment. Fertilizers carrying nitrogen and phosphorus 

 have been very effective in the production of blue grass as well as native pasture grasses. 

 Manure treatments have shown the greatest development of total pasture grasses, while 

 complete fertilizer has been most effective in developing blue grass. — C. R. Orton, 



19S9. Whitney, ]\Iilton. Fundamental principles established by recent soil Investiga- 

 tions. Science 54: 348-351. 1921. — This review covers the work of the U. S. Bureau of Soils 

 for the last 20 or 30 years. The writer points out the results of study of the texture and organic 

 chemistry of the soil, the mineral chemistry of the soil solution, and the colloidal chemistry 

 of the soil. Lists are given of the organic compounds and of the mineral salts that have been 

 identified from the soil. — C. J. Lyon. 



1990. WiEGXER, G. Boden und Bodenbildung in kolloidchemischer Betrachtung. [Soil 

 and soil formation considered from a colloid-chemical standpoint.] 98 -p. Th. Steinkopff: 

 Dresden (fr Leipsic, 1918. — The relation of colloid chemistry to soil formation is treated by 

 chapters as follow^s: (1) Later developments in the study of colloid-chemistry; (2) application 

 of the results to soil science; (3) properties of colloidal solutions and precipitates (solid dis- 

 persions and dispersoids) ; (4) the protective influence of humus upon soil dispersions, humus 

 acting like certain albumens in retarding and preventing the precipitation of colloid particles 

 by electrolytes; (5) the reciprocal precipitation of oppositely charged colloids ("dispersoids") 

 and the formation of interchangeable zeolites; and (6) the formation of soils. In the last, 

 soils are classified and described under 7 types ranging from extremely arid to extremely 

 humid. [Through review by Niblas in Naturw. Zeitschr. Forst- u. Landw. 18: 191-195. 

 1920.]—/. Roeser. 



1991. Wilson, B. D. Sulfur supplied to the soil in rainwater. Jour. Amer. Soc. Agron. 

 13: 226-229. 1921. — A brief summary is given of the amount of sulphur in rain. If sulphur 

 is applied to soils for the express purpose of supplying the needs of plants with an essential 

 element, its application is unnecessary in many localities and is not desirable in the vicinity 

 of large industrial cities. — F. M. Schertz. 



ACIDITY AND LIMING 



1992. Blair, A. W. A comparison of magnesian and non-magnesian limestones. Jour. 

 Amer. Soc. Agron. 13: 220-225. 1921.— Eleven years of work with the 2 forms of Imiestone 

 are reported on 4 different crop rotations. When measured in terms of total nitrogen returned 

 in crops, the magnesian limestone appears to be slightly superior. The 2 limestones have 

 about the same corrective power when measured by the H-ion concentration and by deter- 

 minations of lime requirements of samples of the treated soils. The use of magnesian lime- 

 stone does not indicate any toxic effect. — F. M. Schertz. 



1993. Fre.\r, William. The fineness of lime and limestone application as related to crop 

 production. Jour. Amer. Soc. Agron. 13: 171-184. 1921. — The best limestone for agricultural 

 purposes is said to be that which will pass a 20 or 40 mesh sieve. — F. M. Schertz. 



