SOILS, 1027 



The subsoil, L. Dit.mas {L'Jikj. A(/r. Gemldou.r, 12 {190.?-), No. r>, pp. 25.5-^Gl). — 

 This articU" attempts to show tliat in spite of the prerloiiiinatiiif,' influence attributed 

 to it l)y scientific and practical men, the surface soil is probably of less importance in 

 plant growth than tiie snl)soil for the following reasons: (1) The roots of plants 

 descend as rapidly as possible into the subsoil, in many cases to a considerable depth, 

 the surface soil (0.1 to 0.35 meter) serving the requirements of the i>lant oidy during 

 germination and the early stag;es of growth; (2) the plant draws its water supply 

 largely from that layer of the soil, which has a higher retentive power for water than 

 the surface soil and so holds a reserve for times of neetl; and (.S) the ]ilant only par- 

 tially uses the food supply of the surface soil and draws its nourishment during the 

 greater part of its period of growth from the supply of plant food in the subsoil. To 

 this latter fact may be ascribe<l in part the capricious action of commercial fertilizers. 

 Under ordinary systems of farming the tendency is to enrich the surface soil at the 

 expense of the subsoil. Nature seeks to restore the equililjrium by protnoting in 

 various ways the descent of the fertilizing constituents into the subsoil. Improve- 

 ment of the subsoil by thorough drainage, the occasional growth of deep rooting 

 plants such as the legumes, etc., is advised. The practice of a system whii-h returns 

 a liberal amount of organic m^iure to the soil, as opposed to the exclusive use of 

 commercial fertilizers, is also recommended. 



Humus, F. Sestini {Studi e Riccrche Isl. Lab. C'hiin. Ar/r. Univ. I'im, l'jOO-1901, 

 X<j. 17, pp. 11). — A tliscussion of the formation, properties, and functions of humus. 



Humus as a preservative against frost, W. R. Fishek {Xafurr [Lointan], 65 

 {1901), Xu. 1677, }). i.5i').— Illustrations of the fact stated by Wolhiy that spring an<l 

 autumn frosts are dangerous on peaty soils only when the surface of the latter is dry 

 are reported. 



Experiments on black pocosin soils and methods of treating- them {Bui. 

 Xorlh Carolina Slate Bd. Agr., S3 {1902), Xo 1, pp. 37, 38). — These soils, which occur 

 in consideral)le areas in the eastern part of North Carolina, contain large amounts of 

 organic matter and are quite productive when first cleared, l)ut after a few years' 

 cultivation become absolutely unproductive. The use of lime, potash salts, and 

 acid phosphate has ])een found beneficial. 



Th'" '--iprovement of peaty soils and marsh lands, R. Rogek {./oar. A(/r. Prat., 

 n. Rin:, 3 {1902), Xo. 7, pp. 217-220). 



The decomposition of organic matter in cultivated soils, H. Lagatu {Ann. 

 Ecole X(d. Agr. MoutpelUer, n. aer., 1 {1901), Xo. 1, pp. 6.5-94)- — This is a critical 

 review of the literature of this subject, dealing especially with investigations relating 

 to the comliustion of organic carbon and nitrogen in the soil. 



Studies in nitrification, J. (t. Lipman {Jour, uimer. Chem. Soc, 24 {1902), Xo. 2, 

 pp. 171-186). — Observations on the progress of nitrification in 3-Ib. lots of soil in 6-in. 

 flower pots and 100-gm. samples in 750-cc. Erlenmeyer flasks, are reported. The 

 soils used were (1) a calcareous sand, (2) a loam soil, and (3) an artificial greenhouse 

 soil rich in organic matter. "For the determination of organic and of total nitrogen, 

 the Kjeldahl and the Kjeldahl modified methods were used. The Ulsch and the 

 phenolsulphonic acid methods were used for the determination of nitrates. Of the 

 different methods proposed for the determination of nitrites in the presence of 

 nitrates, the method first proposed by Griess and known as the sulphanilic acid 

 and naphthylamin method was selected because of its convenience and delicacy. 

 Anuiionia was determined by distillation with soda or magnesia, and titration 

 against standard acid or by nesslerizing. For qualitative tests there were also used 

 metaphenylenediamin for nitrites, and brncin and diphenylamin for nitrates." 



The (iriess method for nitrites and the phenolsulphonic acid method for nitrates 

 as u.«ed in these experiments are discussed. The precautions found to be necessary 

 to insure accuracy with the latter are stated. 



