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This article in SSSAJ

  1. Vol. 59 No. 5, p. 1413-1423
    Received: June 21, 1994

    * Corresponding author(s): arshadc@abrsbl.agr.can
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Tillage Effects on Thermal Conductivity of Two Soils in Northern British Columbia

  1. R. H. Azooz and
  2. M. A. Arshad 
  1. Northern Agriculture Research Centre, Agriculture and Agri-Food Canada, Box 29, Beaverlodge, AB, Canada T0H 0C0



Tillage management practices may affect crop growth, in part by altering soil thermal properties. Effects of long-term conventional (CT), no tillage (NT), and modified no tillage (NTR: NT with surface residue pushed away from a 7.5-cm zone over the seed rows) systems on soil thermal conductivity (K) and water content (θ) were evaluated on Donnelly silt loam and sandy loam (Typic Cryoboralfs). Measured K (M1) was compared with calculated K using the McInnes equation (M2) and a modified McInnes equation (M3, which included additional soil properties). The K in both soils increased with an increase in soil θ; the differences among the tillage systems decreased as the soil dried. Soil K for the silt loam was 0.81 (θ = 0.13 m3 m−3), 0.83 (θ = 0.14 m3 m−3), and 0.84 W m−1 K−1 (θ = 0.15 m3 m−3) in CT, NTR, and NT, respectively, at 25 d after planting in 1992 (a dry year). It was 1.13 (θ = 0.42 m3 m−3), 1.53 (θ = 0.50 m3 m−3) and 1.55 W m−1 K−1 (θ = 0.57 m3 m−3) in CT, NTR, and NT, respectively, at 47 d after planting in 1993 (a wet year). Soil K for sandy loam was significantly lower than for silt loam. Soil K measured by M1 and calculated by both the M2 and M3 methods were highly correlated. However, the calculated K values were somewhat improved, although not significantly, with the M3. Mean K was lower by 0.133 W m−1 K−1 in M2 and by 0.045 W m−1 K−1 in M3 than in M1 under CT on silt loam. Increased soil water storage under long-term NT produced a greater thermal contact area and, consequently, a significantly greater K under NT and NTR than CT.

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