Soil Structure and Associated Rooting Behavior in Minesoils

The objective of this study was to identify and describe soil structural patterns and rooting behavior in reclaimed minesoils. The soil chosen for this study consists of approximately 0.4 m of topsoil (A horizon) material placed on approximately 1.5 m of a blend of B horizon, mixed paleoloesses, Sangamon paleosol, and Illinoian till. Four soil pits were excavated, exposing root systems of the corn test crop. Detailed soil and root pattern descriptions were made in each pit. Root patterns were depicted using the profile wall method. An outline of soil structural pattern was superimposed over the root pattern to provide a pictorial relationship between the two. Differences in the physical condition of subsoils were distinguished on the basis of the soil descriptions and statistical analysis of the root length determinations. An artificial soil structure was characterized and attributed to particular mining and reclamation practices. The structural arrangement consists of rounded aggregates loosely compressed together, that fall within the size classes currently used for blocklike and polyhedral aggregates. Plant rooting was distinctly more profuse where this structure was present than where the soil material was massive and compact. It is proposed that structural differences among newly constructed soils are of such significance that they should be carefully characterized and described, and where appropriate used for series level separations. Operations using a mining wheel in combination with belt transportation favor the formation of the more desirable fritted structure, whereas operations using scrapers exclusively favor the formation of the less desirable massive physical condition.