324 EXPERIMENT STATION RECORD. [Vol. 38 



metamorphic rocks, chiefly mica schist, gneiss, granite, and slate in the Pied- 

 mont Plateau section. Twenty-four soil types of 13 series are mapped in 

 addition to swamp, gravel hills, and rock outcrop. Norfolk sand and Norfolk 

 sandy loam predominate, occupying 26.2 and 19.4 per cent of the area of the 

 county, respectively. 



Reconnoissance soil survey of south part of north-central Wisconsin, W. J. 

 Geib, a. E. Taylor, J. B. R. Dickey, C. Thompson, T. J. Dunnewald, and C. B. 

 Post ([/. S. Dept. Ayr., Adv. Sheets Field Oper. Bur. Soils, 1915, pp. 65, pis. 4. 

 flos. 2, map 1). — This survey, made in cooperation with the State of Wisconsin, 

 deals with the soils of an area of approximately 2,985,600 acres in the south 

 part of north-central Wisconsin, comprising Taylor, Lincoln, Clark, and 

 Marathon Counties. A general report and map of this area has already been 

 noted (E. S. R., 16, p. 27). 



The topography of the northern and eastern parts of the area ranges from 

 level to rough and broken, while over the remainder of the area the slopes are 

 long and gentle and there are few lakes and swamps. The .soils of the area 

 are of glacial origin, although the periods of glaciation whicli influenced the 

 regions were separated by long periods of time. Twenty-four soil types of 

 8 series are mapped in addition to areas of peat and rough, stony land, Spencer 

 silt loam and Gloucester silt loam occupying 44.8 and 14.3 per cent of the area, 

 respectively, predominating. 



The composition of the soils of south-central Texas, G. .S. Fraps {Texas 

 Sta. Bui. 213 {1917), pp. 48). — This bulletin reports chemical analyses of 

 samples of soil from an area comprising 19 counties in south-central Texas, 

 previously described and mapped by the U. S. Department of Agriculture 

 (E. S, R., 34, p. 213). Analyses of the surface and subsoils of the various soil 

 types found in the area are tabulated in a comparison of the soils by counties. 

 An interpretation of the analyses with reference to plant food deficiencies is 

 given. 



" Black alkali " in the San Luis Valley, W. P. Headden {Colorado Sta. Bui. 

 231 {1917), pp. 3-15). — Reviewing certain factors thought to be largely 

 responsible for the almost complete loss of fertility of an area of from 400,000 

 to 500,000 acres in the San Luis Valley of Colorado, and based upon his own 

 observations, the author concludes that so-called black alkali, composed largely 

 of sodium carbonate, is the primary cause of the barren soils. The waters of 

 the valley, including the rivers and artesian wells, are carriers of the carbonate, 

 and the practice of subirrigatiou has brought the alkali to the surface by 

 capillarity and evaporation. The presence of white alkali, mostly sodium sul- 

 phate, even in large quantities, and of nitrates, although the latter are .some- 

 times present in sufficient quantities to inhibit growth, are deemed of second- 

 ary importance as compared with the black alkali. The maintenance of a 

 high-water plane (22 to 12 in. from the surface), due to subirrigatiou, as a 

 contributing factor to low production, is also thought to be relatively unim- 

 portant, since good crops are produced by subirrigation in other regions. By 

 actual analyses the soils of the valley were found to be fairly well supplied 

 with the more essential plant food elements. 



It is suggested that the remedy lies in a conversion of the carbonates into 

 sulphates by the use of a sufficient amount of gypsum, for all practical purposes 

 about 9 lbs. of gypsum to 1 lb. of black alkali, and downward washing by means 

 of sui'face irrigation witli furrows or by flooding. While some drainage is 

 deemed necessary to i-eclaim parts of this area, it is still regarded as an open 

 question as to the benefits to be expected from large systems aiming to draiq 

 ^he wjiolp gectiop. 



