Soil structure as influenced by simulated tillage

TitleSoil structure as influenced by simulated tillage
Publication TypeJournal Article
Year of Publication1984
AuthorsPowers, DH, Skidmore, EL
JournalJournal of Soil Science
Pagination879 -884
Accession NumberKNZ0070
Keywordssoil, tillage

Soil is often intensively manipulated by tillage, equipment traffic, and preparation for laboratory analysis. Realizing that manipulated and reconstituted soils have been and are being used in soil structure research, we used surface-soil samples of cultivated and noncultivated Reading silt loam (fine, mixed, mesic, Typic Argindolls) to evaluate the effects of simulated tillage on soil structure and to determine how well the structures of disturbed soils represent the structures of nondisturbed soils of similar composition. Soil cores 86 by 60 mm were formed after the following treatments had been applied: ultrasonically dispersed and freeze- dried, crushed and passed through a 2 mm sieve, and nondisturbed. The soil structural differences were evaluated by soil-water-characteristic curves, saturated-hydraulic conductivities, compression indices, bulk densities, wet and dry aggregate stabilities, and scanning-electron-microscopy. The results show that the soil structures of reconstituted, intensively or even mildly manipulated soils differ considerably from the nondisturbed soils of the same makeup. The greater the disturbance, the greater the differences between the nondisturbed and disturbed soils. The main differences were caused by the destruction of cements and bridges between individual aggregates, which create large, compound-unit (ped) structures. Additional Index Words: dry-aggregate stability, wet-aggregate stability, compression indices, soil-water characteristic, scanning- electron microscopy