Submitted to: Catena
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/16/2003
Publication Date: 6/20/2004
Citation: Shaw, J.N., West, L.T., Bosch, D.D., Truman, C.C., Leigh, D.S. 2004. Parent material influence on soil distribution and genesis in a paleudult and kandiudult complex, southeastern usa. CATENA. 57(2):157-174. Interpretive Summary: Increased attention is being given to site-specific farming, managing different portions of agricultural fields based upon their yield potential and/or environmental risk. Site-specific farming could be improved if detailed, large scale information were available describing how soil properties and parent materials vary across the land surface. Portions of the Coastal Plain region are ideal for collecting this information, even though few such studies have been conducted. Soil formation processes were studied on a site located in the Upper Coastal Plain of Georgia. Large differences in soil properties (capacity to hold and transport water) were found over short distances (100 m). Variations in clay amounts within a soil profile and over short distances from one soil profile to another have direct impact on soil classification, plant available water, water holding capacity, nutrient retention, rooting depth, and water movement thus impacting how producers manage soils. These measurements and our increased understanding of soil variability will assist land managers in developing site-specific farming techniques.
Technical Abstract: Some SE Coastal Plain (CP) associations of upland soils have variable sandy epipedon thickness and argillic horizons of variable texture. Most of these landscapes have developed from episodic fluvial events and we theorize that lateral and vertical parent material variability inherited from fluvial sediments dictates differences in soil distribution. Eleven upland pedons located on an interfluve in the Upper CP were examined and grain size and distrubtion within and between pedons was analyzed. Thickness of sandy eluvial horizons decreased from west to east and soils were mostly in Grossarenic, Arenic and Typic subgroups of Pale- and Kandiudults. Loamy pedons had argillic horizons showing two distinct increases in clay with larger increases between eluvial and illuvial horizons and higher clay amount than sandy pedons. Elevations of the top of the argillic horizon compared to present soil surface suggested that the upper part of the argillic horizon was associated with the contemporary surface. Laterally discontinuous parent materials resulted in a relatively abrupt transition from sandy to loamy argillic horizons across the plot. Horizontal discontinuities as identified by sand grain size distribution and size fraction ratio differences correspond to the bottom of solum and data suggested that these soils had aeolian/fluvial component in the solum, whereas subjacent horizons appeared to be completely fluvially derived. Sandier pedons had attributes of more advanced weathering as evaluated by gibbsite kaolinite ratios that we hypothesized may be due to rapid permeability enhancing leaching and Si loss.