INVESTIGADORES
ROSTAGNO Cesar Mario
artículos
Título:
Desert pavements as indicators of soil erosion on aridic soils in north-east Patagonia (Argentina).
Autor/es:
ROSTAGNO, CÉSAR MARIO; DEGORGUE, GABRIELA
Revista:
GEOMORPHOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2011 vol. 134 p. 224 - 231
ISSN:
0169-555X
Resumen:
Desert pavements are prominent features of many geomorphic surfaces in arid and semiarid lands. In the
semiarid soils of north-eastern Patagonia, gravel cover in the shrub interspace areas of shrub-dominated
communities is generally high, and contrast with that of grass-dominated patches where gravel cover is either
absent or negligible. In the present study we analyze the relationship between soil erosion and desert
pavement formation, in three sites, the upper, middle and lower slope positions of a flank pediment where
well-conserved soils served as reference areas. We used the gravel cover and mass, as well as the thickness of
the remnant A horizon, as determined by the depth of the Bt horizon of a Xeric Calciargid, as measures of soil
erosion. Surface gravel at four cardinal points in respect to mounds associated with shrub-clumps was
collected and the depth to the Bt horizon was determined. The mean thickness of the A horizon in the
well-conserved soils were 11.3, 10.0 and 13.5 cm for the upper, middle and lower slope positions,
respectively. For the same positions, the mean coarse fragment contents (N2.0 mm) in the 010 cm depth of
the A horizon in the well-conserved soils were 144, 92 and 119 g kg−1, and the mean surface gravel mass in
the eroded patches were 5.3, 3.1 and 4.7 kg m−2. Surface gravel mass and depth of the remnant A horizon
gave different estimates of the magnitude of soil erosion in the flank pediment. Thus, the mean/maximum soil
loss, as determined by the mean gravel mass on the soil surface for the upper, middle and lower slope
positions were, 28.3/68.2, 27.0/63.8 and 31.5/56.4 mm, respectively. These figures increased to a mean of 50.0,
52.5 and 82.0 mm for the same positions when soil loss was determined as the difference between the
thickness of the A horizon of the well-conserved soil and that of the remaining A horizon in eroded patches.
The loss of the A horizon by wind and water erosion seems to initiate the change from grass steppe to a stable
shrub steppe characterized, in the shrub interspaces, by well-developed desert pavements. The strong
correlation between surface gravel mass and the thickness of the remaining A horizon indicates that
accelerated soil erosion has played an important role in the formation of desert pavements, and that desert
pavements are good indicators of the extent and intensity of the erosion process in the Punta Ninfas area.
© 2011 Elsevier B.V. All rights reserved.flank pediment where
well-conserved soils served as reference areas. We used the gravel cover and mass, as well as the thickness of
the remnant A horizon, as determined by the depth of the Bt horizon of a Xeric Calciargid, as measures of soil
erosion. Surface gravel at four cardinal points in respect to mounds associated with shrub-clumps was
collected and the depth to the Bt horizon was determined. The mean thickness of the A horizon in the
well-conserved soils were 11.3, 10.0 and 13.5 cm for the upper, middle and lower slope positions,
respectively. For the same positions, the mean coarse fragment contents (N2.0 mm) in the 010 cm depth of
the A horizon in the well-conserved soils were 144, 92 and 119 g kg−1, and the mean surface gravel mass in
the eroded patches were 5.3, 3.1 and 4.7 kg m−2. Surface gravel mass and depth of the remnant A horizon
gave different estimates of the magnitude of soil erosion in the flank pediment. Thus, the mean/maximum soil
loss, as determined by the mean gravel mass on the soil surface for the upper, middle and lower slope
positions were, 28.3/68.2, 27.0/63.8 and 31.5/56.4 mm, respectively. These figures increased to a mean of 50.0,
52.5 and 82.0 mm for the same positions when soil loss was determined as the difference between the
thickness of the A horizon of the well-conserved soil and that of the remaining A horizon in eroded patches.
The loss of the A horizon by wind and water erosion seems to initiate the change from grass steppe to a stable
shrub steppe characterized, in the shrub interspaces, by well-developed desert pavements. The strong
correlation between surface gravel mass and the thickness of the remaining A horizon indicates that
accelerated soil erosion has played an important role in the formation of desert pavements, and that desert
pavements are good indicators of the extent and intensity of the erosion process in the Punta Ninfas area.
© 2011 Elsevier B.V. All rights reserved.N2.0 mm) in the 010 cm depth of
the A horizon in the well-conserved soils were 144, 92 and 119 g kg−1, and the mean surface gravel mass in
the eroded patches were 5.3, 3.1 and 4.7 kg m−2. Surface gravel mass and depth of the remnant A horizon
gave different estimates of the magnitude of soil erosion in the flank pediment. Thus, the mean/maximum soil
loss, as determined by the mean gravel mass on the soil surface for the upper, middle and lower slope
positions were, 28.3/68.2, 27.0/63.8 and 31.5/56.4 mm, respectively. These figures increased to a mean of 50.0,
52.5 and 82.0 mm for the same positions when soil loss was determined as the difference between the
thickness of the A horizon of the well-conserved soil and that of the remaining A horizon in eroded patches.
The loss of the A horizon by wind and water erosion seems to initiate the change from grass steppe to a stable
shrub steppe characterized, in the shrub interspaces, by well-developed desert pavements. The strong
correlation between surface gravel mass and the thickness of the remaining A horizon indicates that
accelerated soil erosion has played an important role in the formation of desert pavements, and that desert
pavements are good indicators of the extent and intensity of the erosion process in the Punta Ninfas area.
© 2011 Elsevier B.V. All rights reserved.−1, and the mean surface gravel mass in
the eroded patches were 5.3, 3.1 and 4.7 kg m−2. Surface gravel mass and depth of the remnant A horizon
gave different estimates of the magnitude of soil erosion in the flank pediment. Thus, the mean/maximum soil
loss, as determined by the mean gravel mass on the soil surface for the upper, middle and lower slope
positions were, 28.3/68.2, 27.0/63.8 and 31.5/56.4 mm, respectively. These figures increased to a mean of 50.0,
52.5 and 82.0 mm for the same positions when soil loss was determined as the difference between the
thickness of the A horizon of the well-conserved soil and that of the remaining A horizon in eroded patches.
The loss of the A horizon by wind and water erosion seems to initiate the change from grass steppe to a stable
shrub steppe characterized, in the shrub interspaces, by well-developed desert pavements. The strong
correlation between surface gravel mass and the thickness of the remaining A horizon indicates that
accelerated soil erosion has played an important role in the formation of desert pavements, and that desert
pavements are good indicators of the extent and intensity of the erosion process in the Punta Ninfas area.
© 2011 Elsevier B.V. All rights reserved.−2. Surface gravel mass and depth of the remnant A horizon
gave different estimates of the magnitude of soil erosion in the flank pediment. Thus, the mean/maximum soil
loss, as determined by the mean gravel mass on the soil surface for the upper, middle and lower slope
positions were, 28.3/68.2, 27.0/63.8 and 31.5/56.4 mm, respectively. These figures increased to a mean of 50.0,
52.5 and 82.0 mm for the same positions when soil loss was determined as the difference between the
thickness of the A horizon of the well-conserved soil and that of the remaining A horizon in eroded patches.
The loss of the A horizon by wind and water erosion seems to initiate the change from grass steppe to a stable
shrub steppe characterized, in the shrub interspaces, by well-developed desert pavements. The strong
correlation between surface gravel mass and the thickness of the remaining A horizon indicates that
accelerated soil erosion has played an important role in the formation of desert pavements, and that desert
pavements are good indicators of the extent and intensity of the erosion process in the Punta Ninfas area.
© 2011 Elsevier B.V. All rights reserved.flank pediment. Thus, the mean/maximum soil
loss, as determined by the mean gravel mass on the soil surface for the upper, middle and lower slope
positions were, 28.3/68.2, 27.0/63.8 and 31.5/56.4 mm, respectively. These figures increased to a mean of 50.0,
52.5 and 82.0 mm for the same positions when soil loss was determined as the difference between the
thickness of the A horizon of the well-conserved soil and that of the remaining A horizon in eroded patches.
The loss of the A horizon by wind and water erosion seems to initiate the change from grass steppe to a stable
shrub steppe characterized, in the shrub interspaces, by well-developed desert pavements. The strong
correlation between surface gravel mass and the thickness of the remaining A horizon indicates that
accelerated soil erosion has played an important role in the formation of desert pavements, and that desert
pavements are good indicators of the extent and intensity of the erosion process in the Punta Ninfas area.
© 2011 Elsevier B.V. All rights reserved.figures increased to a mean of 50.0,
52.5 and 82.0 mm for the same positions when soil loss was determined as the difference between the
thickness of the A horizon of the well-conserved soil and that of the remaining A horizon in eroded patches.
The loss of the A horizon by wind and water erosion seems to initiate the change from grass steppe to a stable
shrub steppe characterized, in the shrub interspaces, by well-developed desert pavements. The strong
correlation between surface gravel mass and the thickness of the remaining A horizon indicates that
accelerated soil erosion has played an important role in the formation of desert pavements, and that desert
pavements are good indicators of the extent and intensity of the erosion process in the Punta Ninfas area.
© 2011 Elsevier B.V. All rights reserved.