Comparison of porosity in a Chernozemic clay loam soil under long-term conventional tillage and no-till

Abstract

Comparison of porosity in a Chernozemic clay loam soil under long-term conventional tillage and no-till. Can. J. Soil Sci. 78: 619-629. Tillage practice can alter soil structure, porosity and the size distribution of pores. Consequently, this study was conducted to compare the long-term (since 1968) effects of conventional tillage (CT) using a heavy-duty cultivator and no-till (NT) on structure and porosity of a Dark Brown Chernozem (clay loam) soil in southern Alberta. Number and porosity of total, round, intermediate and elongated pores, maximum equivalent circular diameter (MECD), and mean circularity of pore sizes 50-500 µm (P-150), 500-1000 µm (P-500) and >1000 µm (P-1000) diameter were quantified. These parameters were determined for three depths (0-10, 10-20 and 20-30 cm) and two orientations (vertical, horizontal) using UV-dye impregnated soil sections and image analysis. The surface soil (0-10 cm) of CT was dominantly granularspongy, but for NT it was dominantly crack to massive. Since tillage treatments were not replicated, only general trends on the effect of tillage and its interaction with depth and orientation are given and probability levels are not reported. Tillage treatment had an influence on P-150 and P-500 pores but little or no influence on P-1000 pores. Mean number and porosity of total and intermediate P-500 pores, which are the most important pore size class for seedling root growth in these soils, were higher for CT than NT for the surface soil, but were higher for NT than CT for the subsoil. For example, the total porosity of P-500 pores was 2.21% for CT and 1.95% for NT at the 0-to10-cm depth, 3.80% for NT and 2.27% for CT at the 10-to 20-cm depth, and 3.18% for NT and 2.80% for CT at the 20-to 30-cm depth. These results suggested a higher potential for seedling root growth in the surface soil of CT, but a greater potential for root growth in the subsoil of NT.Key words: structure, porosity, image analysis, tillage Miller, J. J., Kokko, E. G. et Kozub, G. C. 1998. Effets à long terme du travail du sol classique et du semis direct sur la porosité d'un loam argileux tchernozémique. Can. J. Soil Sci. 78: 619-629. Le mode de travail du sol peut modifier la structure et la porosité du sol, notamment la répartition des pores selon le calibre. L'objet des présents travaux était de comparer les effets de longue durée, depuis 1968, du travail classique du sol (TC) au cultivateurs lourd et du semis direct (SD), sur la structure et sur la porosité d'un loam argileux tchernozémique brun foncé du sud de l'Alberta. Étaient quantifiés le nombre et la porosité des pores totales, sphériques, intermédiaires et allongées, le diamètre circulaire équivalent maximum et la circularité moyenne des calibres des pores, P-150 (50-500 µm), P-500 (500-1000 µm) et P-1000 (+ de 1000 µm). Ces paramètres étaient déterminés pour trois tranches de profondeur : 0-10, 10-20 et 20-30 cm et à deux orientations : verticale et horizontale, à partir de sections de sol imprégnées de résine contenant un colorant UV et par analy...

Micromorphological analysis of soil structure under no tillage management in the black soil zone of Northeast China

“…According to Pagliai et al (2004), a plow pan was formed in the 20-25 cm layer under CT as the macroporosity <10 %. Similar results were found in Pagliai et al (1995) (silt loam soil, 10 years experiment) and Miller et al (1998) (clay loam soil, 24 years experiment). Under CT treatment, tillage operations formed unstable macropores in the upper layer, decreased macroporosity in the lower layer, and a plow pan was observed.…”

Temporal and spatial variability of soil bulk density and near-saturated hydraulic conductivity under two contrasted tillage management systems

“…Tillage treatment was also a significant factor of K variability for the highest matric potentials (≥−0.1 kPa) but not for the lowest matric potentials (Table 3) indicating that tillage had mainly affected macropores (Miller et al, 1998;Kribaa et al, 2001;Wahl et al, 2004). At the beginning of May (set 1), the global geometric mean of K S under conventional tillage was higher than under conservation tillage (71 vs. 44 mm h − 1 ).…”

“…Furthermore, primary tillage operation was done in November under conservation tillage and it was done much later (in April) under conventional tillage. As indicated by Miller et al (1998), the timing of tillage events relative to the measurements has a strong influence on K(h) data. It may completely mask short-term tillage effects.…”

Tillage effects on soil hydraulic properties in space and time: State of the science

“…Alternatively, soil samples impregnated with resin containing fluorescent dye were cut into thin sections, and images of ultraviolet light were analyzed to classify the pore space and quantify the structure (Ringrose-Voase, 1996). The effects of tillage (CT versus NT) on soil structure and porosity have also been studied using ultraviolet-dye-impregnated thin sections of a clay loam (Miller et al, 1998).…”