Published April 8, 2014 Published March 28, 2014 Pedology Vertisols and Vertic Properties of Soils of the Cherokee Prairies of Kansas Soils in the Kansas Cherokee Prairies have formed in various parent materi- Paul E. Hartley als and exhibit differences in the degree of expression of vertic properties. Kansas Livestock Association Despite large clay contents, few soils meet the criteria for a Vertisol. In an Environmental Services, Inc. effort to investigate the cause of these differences, pedogenic processes, pri- 1303 Yucca St. Scott City, KS 67871 marily clay illuviation and shrink–swell processes, were evaluated in eight pedons. Relatively high coefficient of linear extensibility (COLE) values were DeAnn R. Presley* found in all soils. The clay mineralogy of four sites was dominated by smec- Michel D. Ransom tite, but only two of those sites classified as Vertisols. In the other four sites, smectite was the most common clay mineral, yet there were several other Ganga M. Hettiarachchi clay minerals present in significant quantities. Disruption of illuvial clay fea- Dep. of Agronomy tures by shrink–swell movement was evident in the thin sections of all soils. Kansas State Univ. Striated b-fabrics dominated except in surface soils that exhibited a small 2004 Throckmorton Plant Sciences Center COLE value and occurred above an argillic horizon. Linear planes lined with Manhattan, KS 66506-5501 stress-oriented clay and representing zones of shear failure were observed, along with argillans that had been distorted and embedded within the matrix Larry T. West by swelling pressure and soil movement. In conclusion, when present, a non- USDA–NRCS expansive silty surface layer acts as a buffer and may limit shrink–swell by National Soil Survey Center (retired) allowing expansive subsoils to dry more slowly. 100 Centennial Mall North Lincoln, NE 68508 Abbreviations: COLE, coefficient of linear extensibility; MLRA, Major Land Resource Area; XRD, X-ray diffraction. he Cherokee Prairies Major Land Resource Area (MLRA) 112 is an area characterized by gently sloping to rolling, dissected plains situated within Kansas, Missouri, and Oklahoma. In southeastern Kansas, the region is Tbounded on the north by the Kansas River and on the west by the Flint Hills phys- iographic region. Many of the soils in the Cherokee Prairies are characterized by large clay contents and large shrink–swell potential. Although most soils in this region are not classified as Vertisols, their vertic properties and claypan character- istics cause soil management to be difficult and pose problems for agricultural, -en vironmental, and engineering uses. Collecting more information and improving our understanding of the frequency and circumstances where vertic soils are likely to be present are important steps toward improving soil management techniques. A section of MLRA 112 and the area in which all sampling occurred for this study is referred to as the Osage Cuestas physiographic region of Kansas. The Osage Cuestas are named for the low, rolling escarpments that are somewhat steep on one side and gently sloping on the other. Local relief is typically only 1 to 3 m, and major valleys are generally <25 m below adjacent uplands. The region is underlain with alternating layers of shales and limestones of Pennsylvanian and Mississippian age. The soils reflect this geology, and multiple parent materials are often described. Soils form in residuum overlain by colluvium, local alluvium, and/or alluvium. A Contribution 13-153-J of the Kansas Agricultural Experiment Station. Soil Sci. Soc. Am. J. 78:556–566 doi:10.2136/sssaj2013.06.0217 Received 5 June 2013. *Corresponding author ([email protected]). © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Soil Science Society of America Journal thin loess cap is also common on upland areas throughout this ample, although commonly occurring in vertic soils, speckled region. The soils in this study area predominantly have a ther- (asepic), stipple speckled (argillasepic or insepic), mosaic speck- Pedology mic soil temperature regime and a udic soil moisture regime. The led (mosepic), and random striated (omnisepic) were considered region has a humid continental climate with an average annual unrelated b-fabrics by Blokhuis et al. (1988). Void types found in rainfall of 865 to 1145 mm. Most precipitation falls from high- vertic soils are not so different than other soils, although planar intensity, convective thunderstorms from late spring through voids often form at shear planes and tend to dominate the subsoil autumn (NRCS, 2006). The humid climate provides adequate horizons of vertic soils. moisture for the processes of in situ clay mineral formation and The objective of this study was to investigate the macro- and clay translocation. micromorphology as well as the clay mineralogy of selected ver- The genesis of nearly all Vertisols and vertic intergrades is tic soils of the Cherokee Prairies MLRA. In addition, we aimed dependent on two conditions: (i) a large quantity of 2:1 expand- to understand the genesis and pedogenic processes, particularly able clay minerals; and (ii) a seasonal wet–dry cycle that causes clay illuviation and shrinking–swelling and the effect that this the expansion and contraction of the soil material (Soil Survey has on the expression of vertic processes, particularly in this re- Staff, 1999). The spectrum of vertic characteristics and proper- gion where Vertisols are not common. ties is wide. Vertic soils occur in nearly every major climatic zone and under many different vegetation types. Materials AND METHODS The vast majority of vertic soils are dominated by smectite. Field Description and Sampling The smectitic clays may be inherited from the original rock par- Eight pedons representative of the clayey, vertic soils ent material or may have formed in place as a result of neogenesis common to this region were selected for this study (Fig. 1). or transformations from primary minerals. In general, soil-form- Pedons were sampled in the following Kansas counties: Osage, ing processes that lead to the formation of vertic soils control the Franklin, Woodson, Allen, Wilson, and Neosho. Three pedons formation and stability of smectites in soil. Such minerals are were sampled through the spring and summer of 2009: Site A capable of expanding and contracting with changes in the mois- (Bucyrus 09KS139001); Site B (Woodson 09KS059001); and ture status (Eswaran et al., 1988). The expansion and contraction Site C (Summit 09KS207001). The remaining six pedons were of interlayer spaces as well as interparticle shrinkage between sampled and described by NRCS soil scientists before the begin- stacked clay particles and clay particle aggregates (domains) in ning of this study, including: Site D (Woodson 73KS001003); the microstructure is responsible for the shrink–swell phenom- enon that defines vertic soils. Several other minerals can be pres- ent in the clay fraction of vertic soils as well and can be in equal or greater abundance than smectite. For instance, kaolinite, ver- miculite, clay mica, and quartz often can significantly contribute to the clay fraction. At the microscopic level, plasma separations, stress cutans, and planar voids are characteristic of Vertisols and vertic inter- grades (Blokhuis et al., 1988). Lineated zones of oriented plasma (clay particles) in which clay platelets are stacked face to face form within the microfabrics of vertic soils due to the shear stresses as- sociated with swelling. These elongated zones of oriented plasma are known as plasma separations and represent zones of previ- ous shear failure (Coulombe et al., 1996; Wilding and Tessier, 1988). Porostriated (vosepic), granostriated (skelsepic), parallel striated (masepic), and cross-striated (lattisepic) b-fabrics in- dicate microshear (Wilding and Tessier, 1988). Nettleton and Sleeman (1985) cited many researchers who found that shearing produced parallel-striated b-fabrics within the clay-sized mate- rial. Gunal and Ransom (2006a) found that shrink–swell was as- sociated with striated b-fabrics in Bt horizons in central Kansas. Often the striated b-fabrics occurred in the upper part of the argillic horizons with larger COLE values (Gunal and Ransom, 2006a, 2006b). Shearing in both the horizontal and vertical di- rections is believed to produce cross-striated fabric (McCormack and Wilding, 1974). Unrelated plasma separations were not considered characteristic of vertic soils by Blokhuis et al. (1988); Fig. 1. Cherokee Prairies Major Land Resource Area 112 is located however, they are commonly described in these soils. For ex- in Missouri, Kansas, and Oklahoma. Eight sites (labeled A–H) were sampled in Kansas. www.soils.org/publications/sssaj 557 Site E (Zaar 05KS205002); Site F (Zaar 97KS205001); Site G Particular attention was given to the description of the micro- (Kenoma 05KS133003); and Site H (Parsons 06KS133001). All mass and pedofeatures. pedons were sampled by excavating to a depth of 1 to 2 m with a backhoe. Pedons were described using Schoeneberger et al. Laboratory Characterization (2012). For each horizon, bulk samples