SOILS FERTILIZERS. 713 



Investigations on weathering in the Tropics, E. C. J. Mohr (Bui. D6pt. 

 Agr. liuUs Xccrhind., lUOD, \o. ii2, piJ. 26, /rVy-s-. 2). — Investigations on the effect 

 of rain water on freshly ground tertiary basalt under moist warm climatic 

 conditions are reported. 



The rock was used in 3 sizes, J to i, 1 to 1^, and 3 to 4 mm. particles. It 

 was subjected to the action of rain water from July, 1906 to December, 1908, 

 in an apparatus so arranged that in one series the level of the water was above 

 that of the rock particles, and in the other the particles were kept moist by 

 rise of water from below. The principal fact noted in the first series was 

 that the silicic acid corresponding to the decomposed augit and lime feldspar 

 was washed out with the soluble bases while the silicic acid corresponding to 

 the alkali feldsiiar remained behind as kaolin. In the second series, only the 

 silicic acid corresponding to decomposed augit was removed and the silicic acid 

 corresponding to lin)e feldspar remained behind. 



Experiments on the plant food requirements of forest soils and tests of 

 samples of porphyrite soils, II. Vatee {Tharand. Forstl. Jahrb., 59 {1909), 

 No. 2, pp. 177-212). — The methods used in studying the composition and fertilizer 

 requirements of the soils are described. The general result obtained in the 

 fertilizer experiments was that on the i)orphyritic soils poor in silica the turning 

 under of a dead cover 5 cm. (1.97 in.) deep gave only 7 per cent of the in- 

 creased growth of trees obtained with complete manuring, rhosjihoric acid 

 was apparently the fertilizing constituent most needed in the soils e.\i«rimented 

 with. 



Mechanical and chemical analyses of soils, C. A. Weber (Arb. Dciit. Landw. 

 GeseU.. 1909, No. Hi'), pp. I.n-l'i2). — Analyses of a number of marsh soils are 

 reported. 



Chemical composition and fertilizing of the soils of the Taurida Govern- 

 ment, X. DuBROvsKii {Zap. SUnfer. Otd. Imp. Ross. Obshch. Sadov., 1908, July,' 

 abs. in Zltnr. Opuitn. Agron. (liiiss. Jour. Expt. Landw.), 10 {1909), No. .), pp. 

 566-568). — These soils are poor in i»hosi)horic acid but sutficiently i)rovided witli 

 nitrogen and potash. They are therefore greatly benefited by phosphatic fer- 

 tilizei's, which cause a considerable increase of the yields of wheat and rye. 



Analytical study of some soils of southern Italian Somaliland, G. Man- 

 GANO {Agr. Colon. [Ualij], S {1909). No. 6, pp. 398-Jtl3, fig. /) .—Physical and 

 chemical analyses of 40 samples of soils are given, together with detailed 

 observations on the vegetation and physical characteristics of the locality from 

 which each sample was taken. There is also a table showing the status (de- 

 ficiency, sutticiency, or abundance) of each sample of soil in regard to niti'ogen, 

 phosphoric acid, potash, and lime. 



The general conclusion is that most of the soils show a good degree of fertility 

 and that when a sufficient system of irrigation is installed it will be possible to 

 cultivate many of the important economic i)lants of the tropics. 



Nature of the soil and subsoil and the underground waters of the Nile 

 Valley, C. Beauge (Jour. Agr. Prat., n. ser., 19 {1910), No. 3, pp. 89-91; Rev. 

 (rC'iK Agron., n. ser., 5 {1910), No. 1, pp. 4-7). — It is shown that while the soils 

 of the Nile Valley are variable in character, the predominating type in the 

 cultivated area is a silt clay. 



The average of a large number of analyses of samples of this soil shows a 

 composition of silica 45 per cent, clay 53 per cent, magnesia 0.2 to 1.6 per cent, 

 lime 1.3 to 4.9 per cent, nitrogen 0.03 to 0.1 per cent, and phosphoric acid 0.03 to 

 0.3 per cent. There are certain heavy soils which contain as high as 84 per 

 cent of clay and some very light soils containing as high as 68 per cent of sand. 

 The percentage of chlorin notably increases as the Mediterranean Sea is ap- 



