216 EXPERIMENT STATION RECORD. 



tion, fires, the continued use of commercial fertilizers ; all these tend unduly to 

 lower the humus content. This complex organic soil ingredient supplies nitro- 

 gen and available mineral plant food, augments the water storage capacity, 

 promotes its warmth, betters its texture and permeability, and aids micro- 

 organic growth. Seriously to lessen its content in the soil is to lower the crop- 

 producing power of the individual farm and to impair national resources. Its 

 lack may be diagnosed by careful observation, but it is particularly apt to be 

 deficient in the more open and porous soils. The supply is best augmented by 

 adequate crop rotation, using legumes and grass as renovating crops, by the free 

 use of farm manures or by the practice of green manuring." 



A short list of references to articles on the subject is given. 



What the chemist has found in Pennsylvania soils, and the relation of 

 chemistry to agriculture, W. Freak (Penn, Dept. Agr. Bui. 157, pp. 77-94)- — • 

 This article discusses briefiy the origin and general characteristics of the rep- 

 resentative soils of Pennsylvania, reports analyses of a number of typical soils 

 of the State, and explains in some detail the fertilizer requirements of the soils 

 as determined by a series of cooperative fertilizer experiments with farmers in 

 different parts of the State. 



The three main types of soils considered are sedentary, alluvial, and glacial 

 or drift soils. As measured by solubility in both strong acid and in 1 per cent 

 citric acid, the soils are as a rule abundantly supplied with potash. A number 

 of them, however, are deficient in phosphoric acid. A number of the soil sam- 

 ples examined were from limestone regions and therefore abundantly supplied 

 with lime; others were deficient in this constituent. 



The relative merits of different methods of determining the fertilizer require- 

 ments of soils are briefly discussed. 



On soils derived from carboniferous limestone, A. Gregoire {BuI. iS'oc. 

 Chim. Belg., 22 (1908), No. 2, pp. 93-104; Bui. Inst. Chim. et Bad. OemUoux, 

 1908, No. 75, pp. 99-108; abs. in Chem. ZentU., 1908, I, No. 17, p. 1642).— A 

 peculiar unproductive soil of the region of Condroz is described and analyses 

 are reported. This soil, which is locally known as " Flin," is a compact ocher- 

 ous clay containing a large amount of calcium silicate, limonite, and calcareous 

 fossils and also a high percentage of magnesia. Thp peculiar character of the 

 soil is believed to be due to decalcification of carbonifei'ous limestone, resulting 

 in a lack of fiocculation of the clay produced, and not to an excess of magnesia. 

 In view of the fact that the restoration of the lime would be a difficult opera- 

 tion, the author recommends that the soils can best be utilized and improved by 

 putting them down in grass and liming at frequent intervals. 



Where crop yields are curtailed by lack of phosphoric acid and lime in the 

 soil, A. Agee (I'oin. Dept. Agr. Bui. 157, pp. 94-102). — This article calls atten- 

 tion to the fact that while limestone soils are usually fertile soils, abundantly 

 supplied with both lime and i)hos])horic acid, there are cases in which such .soils 

 are benefited by the application of lime and phosphates. The more general use 

 of ground limestone and of fine ground raw phosphate is recommended, par- 

 ticularly in connection with the growth of leguminous crops. 



A contribution to knowledge of the composition of buntersandstein soils, 

 R. HoBNBERGER (ZtscJir. Foist u. Jdgdw., 40 {1908), No. 2, pp. 94-102; abs. in 

 Zentbl. Agr. Chem., 37 (1908), No. 9, pp. 577-579).— Detailed chemical studies 

 of typical soils of this kind are reported. 



Some representative soils, H. Ingle (Transvaal Agr. Jour., 6 (1908), No. 

 22, pp. 238-243). — Chemical analyses of several samples from each of three dis- 

 tricts of the Transvaal are reported, with brief discussions of their fertilizer 

 requirements. 



Analysis of grain soils [of Cape of Good Hope], C. F. Juritz (Agr. Jour. 

 Cape Good Hope, 32 (1908), No. 2, irp. 228-230).— Mechanical and chemical 



