624 EXPERIMENT STATION RECORD. [Vol.35 



It was found that " the sulphur removed in the drainage water from an 

 unplanted, unlimed soil that had received some farm manure but no commercial 

 fertilizer amounted to 44 lbs. per acre annually. The application of lime in- 

 creased the quantity of sulphur removed by the drainage water. Soil on which 

 crops were grown lost less sulphur in the drainage water than did unplanted 

 soil when otherwise similarly treated. The annual application of sulphate of 

 potash at the rate of 200 lbs. per acre markedly increased the quantity of sul- 

 phur in the drainage water. From one-half to two-thirds of the sulphur applied 

 annually as sulphate of potash was removed in the drainage water." 



Physicochemical studies of soils. — IV, The cause of the fixation of phos- 

 phoric acid by the soil, U. Pbatolongo (Staz. Sper. Agr. Ital., 48 {1915), Nos. 

 5-1, pp. 457-J,90. figs. 2; abs. in Chem. ZentU., 1915, 11, No. 17, p. 911). — Con- 

 tinuing previous work (E. S. R., 35, p. 21). experiments with loose alluvial 

 soils, alluvial clay, humus soil, and calcareous clay soils and monobasic phos- 

 phates are reported. The results are taken to indicate that the fixation of 

 phosphoric acid can be attributed to absorption processes by positively charged 

 soil colloids, mainly the hydroxids of iron, aluminum, and manganese, and also 

 to chemical fixation by calcium salts. 



The oxidizing' power of soils, F. C. Geeretsen (Arch. Suikerindus. Nederland. 

 Indie, 23 (1915), No. 21, pp. 833-841, figs. 2; Meded. Proefstat. Java-Suikerindus., 

 5 {1915), No. 11, pp. 311-331, figs. 2; abs. in Chem. Abs., 10 {1916), No. 4, p. 503; 

 Internat. Inst. Agr. [Rome], Mo. Bui. Agr. Intel, and Plant Diseases, 6 {1915), 

 No. 12, pp. 1583, 1584; Jour. Sac. Chem. Indus., 35 {1916), No. 6, p. 372).— In 

 tests with 19 cane soils having normal oxidizing power, it was found that when 

 tested before and after sterilization the amount of iodin liberated by the soils 

 from 1 per cent potassium iodid solution decreased noticeably. This is taken 

 to indicate that " in case soils have an oxidizing power it is at least partly due 

 to oxidases." In six cases where the stand of cane was good from 120 to 354 

 mg. of iodin were liberated by 100 gm. of soil ; in three cases where the stand 

 was fair to moderately poor from 79 to 184 mg. were liberated ; and in eleven 

 cases where the stand was bad there was no iodin liberated in eight cases and 

 up to 47 mg. in the others. " The amount of gaseous oxygen necessary to lib- 

 erate the average amount of iodin would amount to 30 to 100 per cent of the 

 pore space in a heavy clay soil. Hence it is concluded that the poor stand of 

 cane on strongly reducing soils is due to lack of oxygen at the root tip." 



A method of determining the oxidizing power of soil by means of potassium 

 iodid solution is described. 



The principles of crop production, E. J. Rttssell {Jour. Chem. Soc. [Lon- 

 don], 101 {1915), No. 638, pp. 1838-1858, pi. 1, figs. 9; abs. in Nature [London'], 

 96 {1916), No. 2412, pp. 579-583, figs. ^).— This is a brief review of work by the 

 author and othei'S in which the main factors influencing crop production are 

 discussed, special attention being drawn to the so-called limiting factor. 



Soil survey of Walker County, Alabama, J. O. Veatch, A. M. O'Neal, Jr., 

 and J. F. Stroud {U. S. Dept. Agr., Advance Sheets Field Operations Bur. Soils, 

 1915, pp. 30, fig. 1, map 1). — This survey, made in cooperation with the State oE 

 Alabama and issued July 31, 1916, deals with the soils of an area of 510,720 

 acres in northwestern Alabama, the surface of which is prevailingly undulating 

 to hilly, with small areas of extremely rough and broken country. 



" The soils of the greater part of the county are residual in origin, and are 

 derived from shales and fine-grained sandstones. The silt loam and fine sandy 

 loam types of soil predominate. The soils are generally well drained and easily 

 tilled." Exclusive of steep broken land, 12 soil types of 8, series are mapped, 

 of which the Dekalb very fine sandy loam, shale loam, and silt loam, and the 



