814 EXPERIMENT STATION RECORD. 



and brown medium to sandy loams, (5) gray and brownish gray medium to 

 sandy loams, and (6) sandy soils and a number of miscellaneous soils, are 

 also reported. 



" One feature of these soils is their poverty in the silt, fine silt, and very fine 

 silt fractions. In this respect the typical gray soils are better supplied than 

 the typical red sedentary soils, but even they show comparatively small per- 

 centages of the finer silts. The gray soils also contain less fine gravel and 

 ' sand ' and more ' fine sand ' than the corresponding red and brown soils." 



The important cementing material of the soils was found to be iron oxid. 

 Data on the relation between the color of soils and their iron oxid content in- 

 dicate that " the gray soils are very much poorer in iron oxid than the red and 

 brown soils, and the brown soils are as a rule poorer than the red soils 

 except where the humus content is high. The brown in any case is to be re- 

 garded as a mixture of red due to iron oxid, and black due to humus. The 

 percentages of iron oxid in the clay fraction would probably be a better guide, 

 as the iron oxid locked up in the ironstone grains (which are abundant in 

 many soils) can not have much coloring effect." 



Studies of two soils showed that in one case a third and in the other case a 

 quarter of the total phosphoric oxid in the soil was locked up in the ironstone 

 grain. 



Experimental data on podzol formation, V. P. Smirnov {Ezheg. Oeol. i Min. 

 RossU, 14 {1912), No. 7-8, pp. 206-210, fig. 1; abs. in Zhur. Opytn. Agron. {Rtiss. 

 Jour. Expt. Landw.), 15 (1914), No. 3, jjp. 228, 229).— In experiments with a 

 sandy podzol soil two glass tubes 5 cm. in diameter were filled with the soil 

 in its natural stratification, and distilled water, distilled water containing 

 carbon dioxid, and a solution of ammonia were allowed to percolate thi-ough 

 the soil for twenty-four hours. The filtrates contained different amounts of 

 leached-out organic and inorganic constituents, the smallest amount being in 

 the distilled water containing carbon dioxid and the most in the ammonia 

 solution. 



These results, together with preliminary analyses of the soil layers, led to 

 the conclusion that the cementing material of the subhorizons of podzol soil 

 consists of organic matter and colloidal silica. In the tube treated with am- 

 monia a brown ring appeared between the lower subhorizon and the subsoil, 

 which is thought to be an ortstein formation. 



The question of the formation of secondary minerals in the ortstein- 

 producing horizons of soils, B. B. Polynov {Ezheg. Oeol. i Min. RossU, IJf 

 {1912), No. 9, pp. 273-280; abs. in Zhur. Opytn. Agron. {Russ. Jour. Expt. 

 Landw.), 15 {1914), No. 3, p. 228). — A brief morphological description and 

 mechanical and chemical analyses of each layer of two podzol soils are re- 

 ported, together with experiments on the absorptive power of each layer for 

 ammonia. 



A marked increase in absorptive power and in amount of sesquioxids, chemi- 

 cally combined water, alkaline earths, potassium, and mechanical clay (less 

 than 0.01 mm.) was observed in the ortstein-producing subhorizons as com- 

 pared with the upper horizons. The increase in absorptive power for am- 

 monia is attributed to the presence in the ortstein-producing layers of " sec- 

 ondary soil minerals," such as the collodial hydrates of silica and ferric oxid, 

 which have a high absorptive power for ammonia, and also to accumulations 

 in these layers of zeolite-like secondary hydrous aluminum silicates of mag- 

 nesium, potassium, and calcium. 



Alkali or kalar experiments and completion report of the Daulatpur recla- 

 mation station, Sind, G. S. Henderson {Dept. Agr. Bombay Bui. 64 {1914), 

 pp. 34, pis. 6, figs. 2). — In this report experience in the United States and in 



