Residual effects of pipeline construction on agricultural soils of the Canadian prairie.

The return to equivalent capability was evaluated on a >1000 km oil and gas pipeline corridor on the western Canadian prairies. Resource constraints limited this first phase of sampling to soils more likely damaged by disturbance. Three pipelines were selected to span a 55‐year period of construction. Data were collected from four transects established within each of six randomly chosen quarter sections (each 65 hectares) that included reference sites. Laboratory analysis provided data for organic carbon, pH, calcium carbonate equivalent, sodicity, salinity, and particle size distribution. Field procedures were used to obtain data for topsoil thickness, bulk density, aggregate size distribution, and carbonate distribution. The Canadian Land Suitability Rating System was employed to evaluate and compare the land capability (LSRS rating) of three pipelines to that of adjacent reference capability. Pipeline‐reference differences were detected in the topsoil for soil organic carbon (83% of reference), calcium carbonate equivalent (62% higher), and pH (0.4 units higher), and in the subsoil for bulk density (2% higher) and electrical conductivity (a fivefold increase). Carbonates were observed more frequently on the pipelines than on references. Soil organic carbon increased and electrical conductivity decreased with time since construction. The mode of land capability was class 4 on the corridor and class 3 on references. Residual effects remained. Neither soil conservation and reclamation practices, nor natural recovery had yet achieved equivalent capability for the target soil group, representing 17% of the extent of the corridor. [ABSTRACT FROM AUTHOR]