Major oil spill in Alberta likely caused by poor soil compaction

Effects of compaction on aeration and morphology of boreal forest soils in Alberta, Canada

Canadian Journal of Soil Science ◽

10.4141/cjss06037 ◽

2009 ◽

Vol 89 (1) ◽

pp. 45-56 ◽

Cited By ~ 30

Author(s):

A D Startsev ◽

D H McNabb

Keyword(s):

Boreal Forest ◽

Forest Soils ◽

Soil Compaction ◽

Boreal Forests ◽

Warm Season ◽

Soil Morphology ◽

Undisturbed Soil ◽

Protective Measures ◽

Soil Aeration ◽

Poor Soil

Poor soil aeration is a factor limiting the productivity of boreal forests in western Canada. Soil compaction reduces air-filled porosity, which is hypothesized to further restrict soil aeration. Soil morphology at nine clearcut sites in west-central Alberta that had been significantly compacted by ground-based harvesting equipment and soil in an adjacent non-trafficked control were related to air-filled porosity and redox regimes. A warm-season air-filled porosity of about 0.1 m3 m-3 separated soils having adequate or restricted aeration, and was confirmed by redox < 200 mV. The values applied to both the undisturbed and compacted soil. Ratios of Feo:Fed and acid-soluble Fe:Mn in concretions were only associated with hydromorphism of undisturbed soil. Compaction reduced soil aeration for 3–4 yr after harvesting, and changed morphology of moderately well-drained soil to imperfectly drained soil at two of four sites; faster removal of water because of slope or vegetation probably prevented changes at the other two sites. Morphology of better and poorer drained soils was not altered by compaction because they either remain adequately aerated or aeration was naturally restricted. Sites with moderately well-drained soils are most at risk of detrimental soil compaction and in need of protective measures to maintain their productivity in these forests. Key words: Soil morphology, drainage class, air-filled porosity, soil aeration, redox potential, boreal forest soils, compaction

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Soil compaction as the possible cause of wilting and premature ripening of sunflower – Short Communication

Plant Protection Science ◽

10.17221/2759-pps ◽

2010 ◽

Vol 42 (No. 3) ◽

pp. 112-117

Author(s):

K. Veverka ◽

I. Křížková ◽

J. Palicová

Keyword(s):

Soil Compaction ◽

Soil Structure ◽

Short Communication ◽

Early Summer ◽

Causal Organism ◽

Uppermost Layer ◽

Dry Conditions ◽

Possible Cause ◽

Poor Soil ◽

Infective Agent

Brown patches of the size from several square metres to hectares or individual dying plants appeared in otherwise green stands. Affected plants wilt and ripen sooner than healthy ones, causing them to have smaller seeds or none at all in the central part of the heads. Under extreme conditions the plants wilt and die in early summer when they are less than 50 cm high. No infective agent was found as a causal organism. Disturbed plants root only in the upper 10 cm layer of the soil, or just below the surface. Poor soil structure and aeration are supposed to be responsible for limited root development. It prevents a sufficient supply of water to the plants during the hot and dry summer months and causes them to wilt. In contrast to cereals, winter rape and some other field crops that ripen during July, sunflower grows very intensively and needs a good supply of water even towards the end of August and in the first half of September. Thus, sunflower plants rooting only in the shallow uppermost layer of the soil suffer much more than other crops from hot and dry conditions.

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Grazing effects on soil physical properties and the consequences for pastures: a review

Australian Journal of Experimental Agriculture ◽

10.1071/ea00102 ◽

2001 ◽

Vol 41 (8) ◽

pp. 1231 ◽

Cited By ~ 254

Author(s):

K. L. Greenwood ◽

B. M. McKenzie

Keyword(s):

Physical Properties ◽

Soil Compaction ◽

Soil Physical Properties ◽

Grazing Management ◽

Soil Conditions ◽

Physical Conditions ◽

Grazed Pasture ◽

Grazing Systems ◽

Physical Degradation ◽

Poor Soil

Grazing animals exert pressure on the ground comparable to that of agricultural machinery. As a result, soil under pasture can be compacted. In grazing systems based on permanent pastures or rangelands, there is little opportunity to ameliorate poor soil physical conditions through tillage. Hence, it is important to understand the effects of grazing on soil physical properties and the consequent effects of these properties on pasture growth and composition. Most soils under grazed pasture, even those managed to minimise soil physical degradation, will be compacted to some extent. However, the magnitude of this compaction is usually small, and limited to the upper 50–150 mm of the soil. Compaction to greater depth, and other changes in soil physical properties, are more likely in recently tilled or wet soils. The response of pasture to the poorer soil conditions caused by grazing is difficult to determine, but it is likely to be small compared with the defoliation effects of grazing. Maintenance of a vigorous pasture should be a major aim of grazing management and would also achieve the secondary aim of maintaining acceptable soil physical conditions.

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