Drop testing aggregate stability of some soils near Merida, Spain

Bergsma, E.; Valenzuela, Carlos R.

doi:10.1002/esp.3290060310

Cited by 15 publications

(7 citation statements)

References 13 publications

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“…MWD was similar in RG and RS soils, and significantly higher (indicating that aggregates were more stable) in the secondary NG soils. Aggregate stability is an index of soil erodibility, since larger aggregates are less prone to erosion [34][35][36]. We can therefore infer that erosion will be lowest in areas that have been naturally revegetated, in accordance with previous findings that erosion moduli of cropland, RG, and RS soils of the Loess plateau are high (>15 000 t km À2 a À1 ) [37].…”

Section: Aggregate Stabilitysupporting

confidence: 89%

Effects of Vegetation Restoration on Soil Physical Properties in the Wind–Water Erosion Region of the Northern Loess Plateau of China

Mao

Zhang³

et al. 2011

CLEAN Soil Air Water

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In the northern Loess Plateau that has been severely affected by wind-water erosion, shifts from arable land to forest or grasslands have been promoted since 1998, using both native and introduced vegetation. However, there is little knowledge of the ecological consequences and effectiveness of the vegetation restoration in the region. Therefore, relationships between watershed-scale soil physical properties and plant recovery processes were analyzed. The results show that soil physical properties such as bulk density, hydraulic conductivity, mean weight diameter, and the stability of >1 mm macro-aggregates have been significantly ameliorated in the 0-20 cm soil layer under secondary natural grasslands. In contrast, re-vegetation with introduced species such as Caragana korshinskii or Medicago sativa had adversely affected the soil physical properties, probably due to the deterioration of soil water conditions and lower organic matter inputs resulting from severe erosion. Reductions in bulk density and increases in saturated hydraulic conductivity could be used as indicators of soil structure amelioration since they are closely related to most other measured properties. Practical considerations for future re-vegetation projects are suggested, particularly that native species with lower water consumption rates than the introduced species should be used to avoid further soil degradation.

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Section: Aggregate Stabilitysupporting

confidence: 89%

Effects of Vegetation Restoration on Soil Physical Properties in the Wind–Water Erosion Region of the Northern Loess Plateau of China

Mao

Zhang³

et al. 2011

CLEAN Soil Air Water

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“…Instead, aggregates were wet by capillarity from the soil above, so that the percentage of larger aggregates in the ring samples was significantly higher (Table IV). A similar increase in aggregate size with depth below the rainimpacted surface was observed by Briggs (1974) for the &lo mm and 1&20 mm layers of a brown clay and the &5 mm and 5-10 mm layers of a krasnozem.…”

Section: Sampling Techniquesupporting

confidence: 77%

“…The stability of soil aggregates under rain is of major importance for surface sealing and runoff (Hoogmoed and Stroosnijder, 1984) and soil erodibility (Wischmeier and Mannering, 1969;Bryan, 1976). A wide range of tests have been developed to assess aggregate stability under rain.…”

Section: Introductionmentioning

confidence: 99%

Effects of time under rain, sampling technique and transport of samples on size distributions of water‐stable aggregates

Cleary¹,

Loch

Thomas³

1987

Earth Surf Processes Landf

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Two methods for sampling aggregates in the soil surface under simulated rain were compared using two soil types. Results showed that aggregate size distributions obtained by spatula sampling were not significantly different from those obtained using rings buried in the soil surface, provided both were sampled to the same depth. The effect of transporting samples over a distance of 60 km was non-significant when samples were placed in bottles half-filled with rainwater and transported in an upright position. The per cent aggregates > 0125 mm was found to be the most suitable index of aggregate stability for both soils.

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“…Although this procedure is not specifically designed to replicate the real world, it is generally felt desirable to have the aggregates wetted in some way (Bergsma and Valenzuela, 1981;Imeson and Jungerius, 1976). Also, work by Cousen and Farres (in press) shows that moisture content dictates time to breakdown, and the variation of those times about a measure of central tendency becomes smaller, i.e.…”

Section: The Nature Of' the Aggregate And R6le Of' Pretreatmentmentioning

confidence: 99%

“…The major difference between this and the McCalla approach is that the aggregates are prewetted to a known moisture tension, and the critical size of the aperture used to define breakdown is 3mm. Bergsma and Valenzuela (1981), De Meester and Jungerius (1978), Bruce-Okine and La1 (1975), and Grieve (1979), all use similar procedures with some variations in fall height, drop size, length of time for prewetting, rate of drop application, size of aperture to define breakdown, and definition of stable aggregates. These differences are summarized in Table I.…”

mentioning

confidence: 99%

An improved method of aggregate stability measurement

Farres

Cousen

1985

Earth Surf Processes Landf

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The stability of individual soil aggregates to impacting water drops is now regarded as a fundamental parameter required in any soil erodibility assessment. This stability has been measured by the use of single drop rainfall simulators, the characteristics and operation of which have, in the past, shown considerable variation. The drop sizes, impact frequency, drop fall height, chemistry of drop-forming liquid, aggregate pretreatment, and definition of breakdown affect the way in which the apparatus can be used to define stability. Within this paper each one of these characteristics is considered and a piece of apparatus proposed which is believed to give results with increased consistency and replicability. The described apparatus can be readily reproduced in any laboratory situation, and has the added advantage of being not only appropriate for the measurement of indices of stability, but also of providing an environment in which the mechanisms of aggregate breakdown can be investigated.

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Drop testing aggregate stability of some soils near Merida, Spain

Cited by 15 publications

References 13 publications

Effects of Vegetation Restoration on Soil Physical Properties in the Wind–Water Erosion Region of the Northern Loess Plateau of China

Effects of Vegetation Restoration on Soil Physical Properties in the Wind–Water Erosion Region of the Northern Loess Plateau of China

Effects of time under rain, sampling technique and transport of samples on size distributions of water‐stable aggregates

An improved method of aggregate stability measurement

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