618 EXPERIMENT STATION RECORD. [Vol. 36 



Soil survey of Yell County, Arkansas, E. B. Deeteb and C. Lounsbuky 

 (U. S. Dep-t. Agr., Advance Sheets Field Operations Bur. Soils, 1915, pp. ^1, 

 flg. 1, map 1). — This survey, issued January 10, 1917, deals with the soils of a 

 naturally well drained area of 603,520 acres in west-central Arkansas. A large 

 proportion of the county includes mountains, and relatively broad, level to 

 gently rolling intervening valley areas constitute the principal farming land. 

 The upland soils, comprising more than 80 per cent of the area, are of residual 

 origin and consist largely of loams, sandy loams, and stony loams. Including 

 rough stony land and riverwash, 23 soil types of 12 series are mapped, of which 

 the Hanceville stony loam, rough stony land, Hanceville loam, and Conway 

 silt loam cover 33.2, 14.9, 14.8, and 12.1 per cent of the area, respectively. 



Composition of Hawaiian soil particles, W. T. McGeoege {Hawaii Sta. Bui. 

 42 (1917), pp. 12). — A study of the composition of the coagulable and non- 

 coagulable clay grains and an investigation on the composition of the clay, 

 fine silt, silt, fine sand, and coarse sand separates in the important types of 

 Hawaiian soils are reported. The origin of Hawaiian soils and the changes 

 which these soils undergo during disintegration are also discussed. 



A wide variation was found in the composition of soil particles of the same 

 size from different Hawaiian soil types. This variation is attributed primarily 

 to the number and intensity of action of the several weathering agents which 

 are instrumental in the disintegration of the lava. " Iron, titanium, and man- 

 ganese are present in largest amount in the coarse grains. Silica, alumina, and 

 phosphoric acid predominate in the finest particles; lime and magnesia in the 

 coarse grains. The influence of coagulants upon Hawaiian clays varies with the 

 composition of the clay. Those most difficultly coagulable are higher in iron 

 and silica than those readily coagulable." 



Summary of Illinois soil investigations, C. G. Hopkins, J. G. Hosier, and 

 F. C. Bauer {Illinois Sta. Bui. 193 {1916), pp. IfSO-IfSlf, pi. 1, figs. 6).— This 

 bulletin summarizes the results of soil investigations which have been carried 

 on in Illinois since 1901, including systematic soil surveys, chemical analyses, 

 and cultural experiments. Illinois soils exist in 14 great soil areas and in the 

 counties covered by the first 10 soil reports, 62 individual and extremely di- 

 verse soil types have been discovered and grouped into 6 classes as prairie, 

 timber, terrace, ridge, swamp and bottom land, and residual soils. 



" Fertility invoices of the individual soil types show a great variation in the 

 content of the essential plant-food elements. Illinois soils may be deficient In 

 one or more of five plant-food elements, namely, nitrogen, phosphorus, potas- 

 sium, calcium, and magnesium, and they may be either acid or alkaline. Thus 

 the problem of maintaining the fertility of the soil is sometimes complicated, 

 though usually limited essentially to the application of limestone and phosphorus 

 and the turning under of nitrogenous organic matter. 



"As a rule, the results of the field experiments harmonise with the informa- 

 tion given by the chemical composition of the soil. They have shown (1) that 

 the maintenance of organic matter and nitrogen is the greatest practical prob- 

 lem of the Illinois farmer, (2) that phosphorus is the one element of plant 

 food that is most universally deficient, and (3) that limestone must be supplied 

 in abundance to many soils before they can be permanently improved. On the 

 ordinary corn-belt soil, proper treatment has produced a total value for one 

 rotation (1911-1914) of $98.58, as contrasted with $65 where no treatment was 

 given. One dollar invested in rock phosphate has paid returns as follows : 

 First rotation, $1.18 ; second rotation, $1.62 ; third rotation, $2.70. . . . 



" Southern Illinois prairie land has been improved by proper soil treatment so 

 that the total Increase over untreated land has been 207 per cent. On peat 

 soil, potassium has increased corn yields by mere than 30 bu. per acre. On sand 



