Effect of pipeline installation on crop yield and some biological properties of boreal soils

Pipeline construction on the Grey soils of the Canadian boreal plains, whic h have a thin Ah horizon, could have considerable impact on their propertie s and productivity. This study was conducted because the effects of pipelin e installation on crop yield and biological properties of these soils have not been well-documented. Soil was sampled from a Grey Luvisol and a Dark G rey Solod prior to pipeline construction in 1991, and in each of the follow ing 3 yr. The right-of-way (RoW) was divided into three zones: a road (or w ork) area used for vehicular traffic; a trench where the pipeline was burie d; and a pile (or spoil) area where soil was stockpiled during construction . The RoW was cropped to barley (Hordeum vulgare L) in 1992 through 1994. B arley yield was low in 1992 (830-1120 kg ha(-1)), and near average (2050-32 90 kg ha(-1)) in 1993 and 1994. Except for low shoot P concentration (1.1-1 .3 mg g(-1)) in 1992, macronutrient concentrations (N, P and K) in barley t issues were within normal ranges. Soil organic carbon was reduced by 12-28% in all RoW areas in 1993 and 1994. Soil total N was reduced by 29-49% in a ll RoWs in 1992 and increased slightly from those levels in 1993 and 1994. Pipeline construction affected soil microbial biomass carbon (MBC) in the t hree RoW areas differently, and the effect was not consistent from year to year. However, the average level of MBC was not adversely impacted. In 1994 , soil phosphatase activity in the RoW zones tended to be lower as compared to pre-pipeline installation, particularly in the pile area of the Dark Gr ey Solod. It is concluded that although some soil biological properties wer e degraded by pipeline construction, and barley yield was reduced in 1992, crop production in the following 2 yr was not significantly affected.