Short-term legacy effects of feedlot manure amendments on surface soil CO2 efflux under irrigated silage barley in Southern Alberta

• Published in: Canadian Journal of Soil Science 2022, Vol.102 (2), p.309-317
• Main Authors: Miller, J.J., Owen, M.L., Drury, C.F., Chanasyk, D.S.
• Format: Article
• Language: English
• Subjects: Animal manures; Animal wastes; Bedding; bedding material; Bulk density; Carbon dioxide; Clay loam; Clay soils; Composting; effets résiduels; Efflux; feedlot manure; Feedlots; fumier de bovins; Growing season; legacy effects; litière; Loam; manure type; Manures; Moisture content; soil CO2 efflux; Soil dynamics; Soil surfaces; Soil temperature; Soil water; type de fumier; émissions de CO2 du sol
• ISSN: 0008-4271; 1918-1841; 1918-1833
• DOI: 10.1139/CJSS-2021-0128

The short-term legacy effects following long-term (17 yr) feedlot manure application on CO2 efflux for a surface soil (clay loam) were studied over 2 yr (2016–2017) on a Dark Brown Chernozem in southern Alberta. The five treatments were stockpiled (SM) or composted (CM) manure with either straw (ST) or wood-chips (WD) bedding applied at 77 Mg·ha−1 (dry wt.) and an unamended control (CON). Surface soil efflux was measured during the growing season of the 2 yr using the dynamic, closed-chamber method. Ancillary measurements (soil water and temperature, total carbon, bulk density) were also obtained. Soil CO2 efflux was similar (P > 0.05) among the four amended treatments in the first (0.63–0.86 g·m−2·h−1) and second (0.40–0.46 g·m−2·h−1) years. However, soil CO2 efflux was significantly greater for amended than unamended treatments by 54–110% in the first year (CON = 0.41 g·m−2·h−1) and by 33–53% in the second year (CON = 0.30 g·m−2·h−1). Soil CO2 efflux was similar for SM and CM in both years and was significantly greater for WD than ST bedding in the first but not second year. Weak positive correlations (r ≤ 0.39) occurred between soil CO2 efflux and total soil C, water-filled pore space (WFPS), and soil temperature. Overall, our findings suggested that legacy effects of manure may persist for 1–2 yr following discontinued applications, but are mostly restricted to greater soil CO2 efflux for amended than unamended soils.