Effect of subsoil tillage during pipeline construction activities on near-term soil physical properties and crop yields in the right-of-way

Persistence of subsoil compaction in construction right-of-way (ROW) areas is a major cropland concern following installation of underground pipelines. Soil physical disturbance and remediation practices including removal of topsoil, subsoil tillage and replacement of topsoil were investigated in a soybean-corn rotation field, which was located within a pipeline ROW. The objectives of the study were to investigate the effectiveness of subsoil tillage (300 and 450 mm) applied shortly after the pipeline installation used to help restore soil physical properties and to recover crop yields. Soil bulk density, soil cone index and crop yields (soybean and corn) from three ROW trafficked zones (Z1, Z2 and Z3) and adjacent unaffected zones were compared at one year and two years after pipeline installation. Compared to 300 mm of subsoil tillage in the ROW zones, 450 mm of subsoil tillage did not significantly improve the soil bulk density and crop (soybean and corn) yields. Compared to 300 mm of subsoil tillage, 450 mm of subsoil tillage created significantly lower soil cone index values within the treated soil layer. Compared to yield data from the adjacent unaffected zones, the ROW zones (Z1, Z2 and Z3) had statistically significant (p < .05) crop yield declines of 25% in soybean (2017) and 15% in corn (2018). The near-term soil physical properties and crop yield have been improved from the subsoil tillage applied in the affected zones; however, their recovery to normal conditions as in the unaffected areas has not been achieved within the 2-year period.