622 EXPERIMENT STATION EECORD. [Vol. 36 



poor drainage. A type represented in this series, recognized as a good alfalfa 

 soil, is characterized by a high calcium content, but low in content of calcium 

 carbonate." 



Studies of the lime requirements of certain soils, L. J. Wild {Trans, and 

 Proc. New Zeal. Inst., 48 {1916), pp. 513-517). — Tests of the Hutchinson and 

 MacLennan method of determining the lime requirement of soil, which is based 

 on the absorptive capacity of the soil for calcium carbonate presented to it 

 in solution as bicarbonate (E. S. R., 33, p. 622). showed that the method gives 

 results for a given soil which agree sufficiently with what is known from other 

 sources of the lime requirements of that soil for practical purposes. 



" It has been shovm, however, that the result for any given soil varies with 

 the strength of the solution and that in practice it is necessary to make the 

 determination under standard conditions. Either a solution of uniform strength 

 must be employed for all determinations or a correcting factor must be applied," 



Tfee phenomenon of absorption in its relation to soils, .1. A. Prescott {Jour. 

 Agr. Sci. [England}, 8 {1916), No. 1, pp. 111-jlSO, fig. i).— This is a critical re- 

 view of investigations on this subject, dealing with the general facts of ab- 

 sorption, Way's chemical hypothesis, Liebig's physical hypothesis, Knop's com- 

 promise and analytical method, absorption of acid radicals, effect of tempera- 

 ture on absorption, absorption by humus, the conception of colloids, adsorption, 

 and adsorption isotherms. Particular attention is given to the applications of 

 absorption phenomena to soils. 



The definition of soil fertility by means of the analysis of plants, P. 

 Sawin (Sawine) {Zhur. Opytn. Agron. {Jour. Agr. Expt.), 11 {1916), No. 1, 

 pp. 1-12; abs. in Chem. Abs., 10 {1916), No. 22, pp. 2950, 295i ) .—Experiments 

 are reported, the results of which are taken to indicate the following: 



Oat grains contain phosphoric acid almost exclusively in organic combina- 

 tions. Phosphates are generally in the straw. The percentage of organic phos- 

 phoric acid in an entire plant varies between very narrow limits, which ex- 

 perimentally were found to be from 0.41 to 0.6 per cent. The size of harvest 

 does not influence this, and the amount of phosphoric acid which has entered 

 the plant influences it only to a small degree. If phosphoric acid is abundant 

 in the nutritive solution it enters into the plant in greater quantity, but it is 

 only an insignificant part which takes an organic form, the greater part entering 

 the straw as phosphates. The quantity of phosphates in the straw varies ac- 

 cording to the conditions of a given vegetative period. It is concluded that for 

 this reason the conditions relating to phosphoric acid can not be used for 

 indicating soil fertility. The total phosphoric acid in the straw and in the 

 entire harvest can, however, indicate the need for phosphatic fertilization. 



Certain biolo^cal chemical processes in relation to the humification of 

 plant residues, A. Trusov (Tboussoff) {Zhur. Opytn. Agron. {Jour. Agr. 

 Expt.), n {1916), No. 2, pp. 165-179, figs. 8). — The various processes and prod- 

 ucts involved in humification and the complex mixture known as humic acid 

 are discussed. 



Studies on soil protozoa and their relation to the bacterial flora, I, II, 

 J. M. Sherman {Jour. Bad., 1 {1916), Nos. 1, pp. 35-66; 2, pp. 165-185).— 

 Studies conducted at the Wisconsin Experiment Station on the life and activi- 

 ties of soil protozoa, with special reference to their influence on the numbers of 

 soil bacteria, are reported. 



In the soil studied the flagellates were the predominating type of protozoa. 

 Colpoda cucullus appeared to be the most widely distributed ciliate. It was 

 found that the ciliates C. cucullus, Balantiophortis elongatus, and Oxytricha sp. 

 are not active under ordinary soil conditions. The bacterial flora in soils con- 

 taining protozoa and free of protozoa behaved in exactly the same way wheti 



