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| Titel |
Effects of tractor loads and tyre pressures on soil compaction in Tunisia under different moisture conditions |
| VerfasserIn |
Chiheb Khemis, Khaoula Abrougui, Lidong Ren, Eunice Ann Mutuku, Sayed Chehaibi, Wim Cornelis |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250150727
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| Publikation (Nr.) |
 EGU/EGU2017-15218.pdf |
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| Zusammenfassung |
| Vegetables in Tunisia demand frequent tractor traffic for soil tillage, cultural operations and
phytosanitary treatment, resulting in soil compaction. This study evaluates the effects of four
levels of compaction by using different loads and tyre pressures of tractors, i.e., load 1 (C1) =
1460 kg, load 2 (C2) = 3100 kg, tyre pressure 1 (C3) = 800 kg cm−2, tyre pressure 2
(C4) = 1500 kg cm−2 on the hydraulic and physical properties of a sandy loam
(10% clay, 20% silt, 68% sand) under three natural moisture conditions H0, H1
(15 days later), H2 (30 days later). At H0 average water content between 0 and
30 cm depth varied from 0.04 to 0.06 kg kg−1, at H1 between 0.13 and 0.07 kg
kg−1, and at H2 between 0.10 and 0.09 kg kg−1. Each test run was limited to one
pass. Undisturbed soil cores were collected in the topsoil (0–10 cm), at 10–20 cm
and in the subsoil (20–30 cm) below the trace of the wheel at sites in the Higher
Institute of Agronomy of Chott Mariam, Sousse, Tunisia. Soil compaction level was
determined by penetration resistance using a penetrologger. Porosity, bulk density and
permeability were then determined to evaluate the impact of the four load/tyre pressure
combinations at the three moisture conditions on soil compaction. Prior to the experiment
(C0), bulk density was 1.4 Mg m−3. After the tractor pass, the highest degree of
compaction was observed with tractor load C2 and tyre pressure C4 which significantly
changed soil bulk density resulting in values of up to 1.71 Mg m−3 in the topsoil and
compacted subsoil under H2, which is significantly above the critical value of 1.6
Mg m−3 for soils with clay content below 17.5%. The high degree of compaction
significantly affected penetration resistance and porosity of both topsoil and subsoil
layers accordingly. Permeability was significantly reduced as a result of the induced
compaction. The results demonstrate that different degrees of soil compaction under
different moisture levels could greatly influence hydraulic and physical properties in
different ways. Even under relatively low water contents, i.e., below or near field
capacity, substantial top and subsoil compaction was induced after one tractor pass. |
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