Soil crusts and deposits as sheet erosion indicators in southern Mali

Bodnar, F.; Hulshof, J.

doi:10.1111/j.1475-2743.2006.00010.x

Cited by 17 publications

(8 citation statements)

References 7 publications

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“…Thus it might be presumed that the dunes store noteworthy amounts of soil water from precipitation. It may be caused by a water-storing effect of the coarse sand, which allows deep percolation and minimizes runoff and evaporation losses, and thus can be expected to provide storage of plant available water (compare Ganssen 1968;Weidelt 1989;Minnich 1995;Bodnar and Hulshof 2006). According to the author's own observations, even after a little rainfall of less than 10 mm, the surface dries fast (illustrated in Fig.…”

Section: Discussionmentioning

confidence: 99%

Tree water potentials supporting an explanation for the occurrence of Vachellia erioloba in the Namib Desert (Namibia)

Krug

2017

For. Ecosyst.

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Background: Site-vegetation relations of Vachellia erioloba, Faidherbia albida, Euclea pseudebenus and Tamarix usneoides in two contrasting locations in the Namib Desert (Namibia) were evaluated with the goal to relate soil water availability to the occurrence of trees under hyper-arid conditions. Methods: Plant water potentials were measured using a pressure chamber in the field. Pre-dawn water potentials were assessed to reflect the soil water potential of the rhizosphere. Midday water potentials were measured to assess the strongest negative water potential applied by the sample trees. Results: Pre-dawn water potentials and midday water potentials indicated access to soil water in the rhizosphere and by this, provide an explanation for an occurrence of V. erioloba within the extreme environmental conditions of sand dunes in the Namib Desert. Diurnal ranges seem to reflect more and less suitable stands, in terms of soil water availability, within the sampling sites. While the impact of the ephemeral Kuiseb river on soil water availability was assessed through the four species' plant-internal water relations, comparable pre-dawn water potentials of V. erioloba at both sites indicate soil water availability also in the dunes of Namibrand. The extreme midday water potentials of the dune plants possibly show the upper limit of tolerance for V. erioloba. Conclusions: The preliminary data provide an explanation of the occurrence and distribution of the investigated species in beds of ephemeral rivers and on dunes under the hyper-arid climatic conditions of the Namib Desert and qualify suitability within the assessed sites. Understanding the plant-physiological processes and assessing the plant-internal water potential provides a valuable tool to evaluate soil water availability within the rhizosphere and to describe an adaptation potential of investigated species. The comparability of pre-dawn water potentials at both sites indicates unexpected soil water availability within lower parts of the dunes of Namibrand. Further research needs are derived concerning the origin and distribution of such soil water. These species in these specific tree-environments are understudied and little published, thus the results support an improved understanding of the ecology in arid environments.

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Section: Discussionmentioning

confidence: 99%

Tree water potentials supporting an explanation for the occurrence of Vachellia erioloba in the Namib Desert (Namibia)

Krug

2017

For. Ecosyst.

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“…the former occurs in high terrains and the latter occurs in surface depressions. Therefore, the spatial variability of these crusts is another factor influencing the infiltration capacity of tilled soil (Fox et al , ; Bodnar and Hulshof, ; Valentin, ). Bielders et al () believed that surface topography is an essential factor contributing to crust development.…”

Section: Introductionmentioning

confidence: 99%

Effects of different spatial distributions of physical soil crusts on runoff and erosion on the Loess Plateau in China

Lü

Xie

Wang

et al. 2017

Earth Surf Processes Landf

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The response of runoff and erosion to soil crusts has been extensively investigated in recent decades. However, there have been few attempts to look at the effects of spatial configuration of different soil crusts on erosion processes. Here we investigated the effects of different spatial distributions of physical soil crusts on runoff and erosion in the semi-arid Loess Plateau region. Soil boxes (1.5 m long × 0.2 m wide) were set to a slope of 17.6% (10°) and simulated rainfall of 120 mm h −1 (60 minutes). The runoff generation and erosion rates were determined for three crust area ratios (depositional crust for 20%, 33%, and 50% of the total slope) and five spatial distribution patterns (depositional crust on the lower, lower-middle, middle, mid-upper, and upper slope) of soil crusts. The reduction in sediment loss ('sediment reduction') was calculated to evaluate the effects of different spatial distributions of soil crusts on erosion. Sediment yield was influenced by the area ratio and spatial position of different soil crusts. The runoff rate reached a steady state after an initial trend of unsteadily increasing with increasing rainfall duration. Sediment yield was controlled by detachment limitation and then transport limitation under rainfall. The shifting time of erosion from a transport to detachment-limiting regime decreased with increasing area of depositional crust. No significant differences were observed in the total runoff among treatments, while the total sediment yield varied under different spatial distributions. At the same area ratio, total sediment yield was the largest when the depositional crust was on the upper slope, and it was smallest when the crust was deposited on the lower slope. The sediment reduction of structural crust (42.5-66.5%) was greater than that of depositional crust (16.7-34.3%). These results provide a mechanistic understanding of how different spatial distributions of soil crusts affect runoff and sediment production.Note: SAR, small area ratio of depositional and structural crusts at 20%; MAR, medium area ratio of the crusts at 33%; LAR, large area ratio of the crusts at 50%.

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“…deposits are good indicators. The advantage of soil crusts and deposits is that they are found in most fields, unlike gullies, and that they correlate well with both erosion risk and with crop yield (Bodnár and Hulshof, 2006). During observations halfway the rainy season, structural crusts were found in all fields, in situ depositional crusts in 59% of the fields, and runoff deposit of fine and coarse sand in 54% and 95% of the fields, respectively.…”

Section: Erosion Controlmentioning

confidence: 92%

“…However, only observations done halfway the rainy season are useful as erosion indicators. Towards the end of the rainy season, runoff deposit of coarse sand is gradually covered with runoff deposit of fine sand and in situ depositional crusts (Bodnár and Hulshof, 2006).…”

Section: Structural Crustmentioning

confidence: 99%