Pedosphere 18(4): 421--430, 2008
ISSN 1002-0160/CN 32-1315/P
©2008 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Evaluating the effect of tillage on carbon sequestration using the minimum detectable difference concept |
X. M. YANG1 , C. F. DRURY1, M. M. WANDER2 and B. D. KAY3 |
1 Agriculture and Agri-Food Canada, Harrow, Ontario, N0R 1G0 (Canada)
2 Department of Natural Resources and Environmental Science, University of Illinois at Urbana-Champaign, Urbana, IL61801 (USA)
3 Department of Land Resources, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada) |
| ABSTRACT |
| Three long-term field trials in humid regions of Canada and the USA were used to evaluate the influence of soil depth and sample numbers on soil organic carbon (SOC) sequestration in no-tillage (NT) and moldboard plow (MP) corn (Zea mays L.) and soybean (Glycine max L.) production systems. The first trial was conducted on a Maryhill silt loam (Typic Hapludalf) at Elora, Ontario, Canada, the second on a Brookston clay loam (Typic Argiaquoll) at Woodslee, Ontario, Canada, and the third on a Thorp silt loam (Argiaquic Argialboll) at Urbana, Illinois, USA. No-tillage led to significantly higher SOC concentrations in the top 5 cm compared to MP at all 3 sites. However, NT resulted in significantly lower SOC in sub-surface soils as compared to MP at Woodslee (10-20 cm, P = 0.01) and Urbana (20-30 cm, P < 0.10). No-tillage had significantly more SOC storage than MP at the Elora site (3.3 Mg C ha-1) and at the Woodslee site (6.2 Mg C ha-1) on an equivalent mass basis (1350 Mg ha-1 soil equivalent mass). Similarly, NT had greater SOC storage than MP at the Urbana site (2.7 Mg C ha-1) on an equivalent mass basis of 675 Mg ha-1 soil. However, these differences disappeared when the entire plow layer was evaluated for both the Woodslee and Urbana sites as a result of the higher SOC concentrations in MP than in NT at depth. Using the minimum detectable difference technique, we observed that up to 1500 soil sample per tillage treatment comparison will have to be collected and analyzed for the Elora and Woodslee sites and over 40 soil samples per tillage treatment comparison for the Urbana to statistically separate significant differences in the SOC contents of sub-plow depth soils. Therefore, it is impracticable, and at the least prohibitively expensive, to detect tillage-induced differences in soil C beyond the plow layer in various soils. |
| Key Words: carbon sequestration, minimum detectable difference, moldboard plow, no-tillage, soil depth |
| Citation: Yang, X. M., Drury, C. F., Wander, M. M. and Kay, B. D. 2008. Evaluating the effect of tillage on carbon sequestration using the minimum detectable difference concept. Pedosphere. 18(4): 421-430. |
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