181-7 Spectral Spatial Analysis Leads to a Better Understanding of Penetrometer Resistance.



Tuesday, October 18, 2011: 9:35 AM
Henry Gonzalez Convention Center, Room 213A, Concourse Level

Edwin Ritchey, Ole Wendroth, Robert Pearce and John H. Grove, University of Kentucky, Lexington, KY
Tobacco is a crop that typically relies heavily on tillage.  As tillage intensity increases so does the probability of compaction.  This study was initiated to measure the extent of the impact of subsoil tillage in both moldboard plowed (MP) and no-tilled (NT) soils, using penetrometer resistance (PR).  Subsurface tillage was done following MP and prior to transplanting.  Penetrometer resistance data were collected following harvest, over the 0 to 45 cm depth increment, at an average moisture content of 0.235 g-1 g-1 (range of 0.229 to 0.245 g-1 g-1).  The PR data were examined with ANOVA and spectral spatial analysis.  The ANOVA analysis indicated that PR was greater at the 0 to 15 cm depth in subsoiled NT soils and lower below this depth in subsoiled MP soils.  The NT soils had greater bearing capacity due to a stable, undisturbed soil structure.   The ANOVA analysis found differences in PR at certain depths and distances from the row, but did not suggest responsible processes.  Spectral analysis diagnosed the field operations causing PR differences.  Subsurface tillage impacts were evident in both primary soil tillage systems, but were more prominent in NT soil.  Row position, due to soil loosening of the transplanter, was always evident but was rarely detected below 15 cm.  Wheel traffic was detected in both MP and NT soils, but was more pronounced under MP.  Traffic from different field operations was more identifiable in MP soils that were also subsoiled.  Spectral analysis was made possible by PR data that were not randomly acquired, but rather were recorded at regular intervals, both with depth and perpendicular to the general direction of field operations.  The use of both classical and spatial statistical analysis provided complementary insights into the differences in soil properties resulting from the different soil tillage management systems.
See more from this Division: ASA Section: Agronomic Production Systems
See more from this Session: General Agronomic Production Systems: I