FORMATION AND BREAKDOWN OF Co60-TAGGED WATER-STABLE SOIL AGGREGATES IN A NORTON SILT LOAM SOIL

Toth, S. J.; Alderfer, R. B.

doi:10.1097/00010694-196010000-00005

Cited by 11 publications

(11 citation statements)

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“…However, Coughlan et al (1973) found that after wetsieving macroaggregates of various sizes separated by dry sieving, the size distribution of the unstable portions was similar and independent of the dry aggregate size. In an earlier study, Toth and Alderfer (1960) traced the fate of labelled aggregates and found that as the size of the labelled aggregate decreased, its contribution to the formation of larger aggregates decreased. Together, these results suggest that the architecture of aggregates may be definable and predictable.…”

Section: Theorymentioning

confidence: 99%

A modeling approach to quantifying soil macroaggregate dynamics

Plante¹,

Feng²,

McGill³

2002

Can. J. Soil. Sci.

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. 2002. A modeling approach to quantifying soil macroaggregate dynamics. Can. J. Soil Sci. 82: [181][182][183][184][185][186][187][188][189][190]. While several researchers have suggested that soil aggregate turnover is a significant control on organic matter dynamics, the quantification of soil aggregate dynamics has yet to be achieved. Quantification of soil aggregate turnover is essential to testing any hypothesis concerning the relationship between aggregate turnover and organic matter dynamics. The goal of the current work was to propose a modeling approach to the quantification of soil macroaggregate dynamics. The approach taken was to define model compartments representing water-stable soil aggregate size fractions and describing the flows between compartments using first-order kinetics. Soil aggregate data from a 2-yr field study on two contrasting soils were used to calibrate the model and yielded soil aggregate mean residence times ranging from 4 to 95 d, where aggregate dynamics were generally two to three times more rapid in a Gray Luvisol compared to a Black Chernozem. The model was subsequently used to predict the distribution of applied tracer spheres in water-stable aggregate size fractions from an initially free state. The models closely predicted the Dy "mean weight diameters" (Dy-MWD) after two growing seasons. While the models have several limitations, they offer the first attempt to quantitatively describe soil macroaggregate dynamics, which is essential to predicting the response in organic matter dynamics to changes in aggregate dynamics. [181][182][183][184][185][186][187][188][189][190]. Plusieurs chercheurs soutiennent que la rotation des agrégats dans le sol commande sensiblement la dynamique de la matière organique. Pourtant, nul n'a encore quantifié la dynamique des agrégats du sol. Avant de tester la moindre hypothèse sur les liens entre la rotation des agrégats et la dynamique de la matière organique, il importe de quantifier cette rotation. L'étude dont il est question ici avait pour but la création d'un modèle qui permettrait de quantifier la dynamique des macro-agrégats dans le sol. L'approche retenue consistait à paramétrer les compartiments du modèle correspondant aux fractions hydrostables d'agrégats d'une granulométrie donnée et à décrire les échanges entre ces compartiments par la cinétique au premier degré. Les auteurs se sont servis des données sur les agrégats recueillies lors d'une étude sur le terrain de deux ans, sur deux sols contrastants, pour étalonner leur modèle. Ils ont obtenu un temps de rétention moyen de 4 à 95 jours pour les agrégats, la dynamique des agrégats étant généralement 2 à 3 fois plus rapide dans le luvisol gris que dans le tchernoziom noir. Par la suite, ils ont utilisé le modèle pour prévoir la répartition de traceurs sphériques, de l'état libre aux fractions hydrostables de granulométrie donnée. Les modèles prédisent étroitement le rapport entre le Dy et le diamètre moyen pondéré après deux périodes végétatives. En dépit de leurs limites, ces m...

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Section: Theorymentioning

confidence: 99%

A modeling approach to quantifying soil macroaggregate dynamics

Plante¹,

Feng²,

McGill³

2002

Can. J. Soil. Sci.

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“…Given the successes of the artificial gamma‐emitting radionuclides, caesium‐134 ( 134 Cs; t 0.5 = 2.06 years; measured at 604 keV) and cobalt‐60 ( 60 Co; t 0.5 = 5.26 years; measured at 1,171 keV), in previous sediment‐related work (Greenwood, ; Greenwood, Walling, & Quine, ; Quine et al, ; Syversen, Øygarden, & Salbu, ; Toth & Alderfer, ), they were selected as tracers in this investigation. Open‐source material was supplied by Eckert & Zeigler Isotope Products (Berlin) in the chemical forms, caesium chloride (CsCl) and cobalt chloride (CoCl 2 ), both in 0.1 M hydrochloric acid (HCl).…”

Section: Methodsmentioning

confidence: 99%

Documenting soil redistribution on livestock‐poached pasture using caesium‐134 and cobalt‐60 as tracers

Greenwood

Meusburger

2018

Land Degrad Dev

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Poaching is caused by the excessive trampling of soil and vegetation by herd animals and is prevalent in intensively managed grasslands. It is viewed as detrimental to soil fertility, has the potential to contribute to soil erosion, and thus represents a form of land degradation that is unsustainable. Attempts to document sediment redistribution by poaching have been hampered by a lack of techniques capable of measuring the movement of poached material at requisite spatial and temporal scales. We present a new tracing technique, using caesium‐134 (134Cs) and cobalt‐60 (60Co), which is designed to overcome those problems. Nine areas (plots) of grassland, each measuring 0.04 m2, were directly labelled with a known activity of either 134Cs or 60Co. Three plots were located on level, unpoached ground for use as controls, and six were located in livestock‐poached areas. Initial surface inventories were documented and then remeasured on three occasions after rainfall. Inventory changes were converted to estimates of sediment redistribution, which was documented across all poached plots at each remeasurement. Erosion represented the predominant mechanism, with average soil losses estimated at an equivalent of 0.03 kg m−2 d−1 at the first remeasurement (T1), 0.11 kg m−2 d−1 at T2, and 0.18 kg m−2 d−1 at T3. Despite assuming erosion would diminish, increasing soil loss is attributed to reduced surface roughness. These findings not only confirm the viability of the tracing technique but also demonstrate that livestock‐poached areas act as sediment sources over timescales of at least a few months after poaching has ceased.

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“…The success of the labelling technique culminated in the same authors conducting a year-long investigation into the formation and breakdown of the 60 Co-labelled WSAs [56]. The reported success of both the labelling technique and the tracing application provided an initial indication of the potential value of 60 Co as a candidate for sediment tracing work of a similar nature.…”

Section: Cobaltmentioning

confidence: 99%

“…[30,31,38,40,[53][54][55][56]), their use in erosion investigations has attracted surprisingly little attention over the last ca. 50 years.…”

Section: Artificial Gamma-emitting Radionuclides As Sediment Tracersmentioning

confidence: 99%

“…Studies that have made reference to those particular characteristics do not discuss its toxicity potential in great detail (e.g. [51,55,56,69,74,75]) but infer that its likely rate of transfer and accumulation from soils into and through the food chain and its injurious potential to organisms at low concentrations are minimal. This inference is corroborated, albeit by logic alone, via the wide variety of ecological and medical tracing applications where 60 Co has been introduced onto, or into, numerous organisms (including humans) during tracing investigations, some of which are listed in Table 1.…”

Section: Cobaltmentioning

confidence: 99%

See 1 more Smart Citation

A Review of the Radionuclide, Cobalt-60, as a Fine-Sediment Tracer

Greenwood¹

2017

Cobalt

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The chapter firstly outlines the global crisis concerning accelerated soil erosion, the implications that this could have on longer-term food security and ways that soil loss has been quantified originally through catchment-scale monitoring but with a recent shift toward the use of sediment tracers. It then briefly reviews some of the most commonly used tracers in sedimentation studies, before focusing on artificial, gamma-emitting radionuclides, and in particular, on Cobalt-60 (Co-60). Some historical background information on previous uses of Co-60 are then provided, and the suite of key environmental characteristics that, from the perspective of studies in hydrology and geomorphology, make Co-60 a potentially attractive candidate for fine-sediment tracing. The chapter then outlines and reviews three ways in which Co-60 has been experimentally applied in varying erosion and sedimentation scenarios where most of the more commonly used tracers would be unsuitable or would lack the level of sensitivity needed to return meaningful data. It then outlines some of the notable drawbacks associated with using Co-60, before highlighting refinements and prospects for future work. The chapter finally concludes by evaluating the versatility and efficacy of Co-60 as a fine-sediment tracer.

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FORMATION AND BREAKDOWN OF Co60-TAGGED WATER-STABLE SOIL AGGREGATES IN A NORTON SILT LOAM SOIL

Cited by 11 publications

References 0 publications

A modeling approach to quantifying soil macroaggregate dynamics

A modeling approach to quantifying soil macroaggregate dynamics

Documenting soil redistribution on livestock‐poached pasture using caesium‐134 and cobalt‐60 as tracers

A Review of the Radionuclide, Cobalt-60, as a Fine-Sediment Tracer

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