UBC Theses and Dissertations
Assessing the impacts of agriculture on soil quality in a five-year crop-livestock rotation in the Fraser River delta, British Columbia Augustinowicz, Grace
The Fraser River delta is one of the most intensively farmed agricultural regions of Canada. It is also an area of high ecological significance, providing habitat for migrating bird populations and aquatic species. To help provide habitat for bird populations, a five-year crop rotation has been developed for the Alaksen Wildlife Area. This rotation integrates perennial and annual crops and livestock production and could provide a promising alternative to intensive production in the region. A study of key soil quality indicators was conducted within the Alaksen to: i) compare key soil quality indicators to assess the impacts of land use type on soil quality, and ii) evaluate the effects of specific rotation practices (crop type, livestock) on key indicators to better understand the potential impacts of the five-year rotation on soil quality. In the fall of 2018, soil samples were taken from sixteen agricultural fields, three abandoned agricultural fields (old fields), and three relatively undisturbed forest patches and analyzed for soil organic carbon (SOC), bulk density (BD), pH and electrical conductivity (EC). Results showed that in the upper 15 cm depth agricultural and old fields, respectively, had 44% and 60% of the SOC as forest patches. Bulk density was 53% greater in agricultural fields than in old fields and 66% greater than forest in the upper 15 cm depth. There were no significant differences in soil indicators between annual and perennial crops fields, except for EC in annual crop fields, which was 52, 40 and 164% greater in the 0-15, 15-30, and 30-60 cm depth, respectively. Fields with livestock showed greater SOC and EC, and lower pH levels at some soil depths. Results of this study suggest that agriculture has negatively affected soil quality within Alaksen but these impacts varied with management. While including perennial crops in the rotation did not improve soil quality, including livestock offered some soil quality benefits, and merits further study based on its potential to improve soil quality in the region.
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