Journal ArticleDOI
Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology
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In this paper, a unified framework for the measurement of aggregate stability is proposed to assess a soil's susceptibility to crusting and erosion, which combines three treatments having various wetting conditions and energies (fast wetting, slow wetting and stirring after pre-wetting).Abstract:
Summary
Crusting and erosion of cultivated soils result from aggregate breakdown and the detachment of soil fragments by rain, and the susceptibility of soil to these processes is often inferred from measurements of aggregate stability. Here, theories of aggregate breakdown are reviewed and four main mechanisms (i.e. slaking, breakdown by differential swelling, mechanical breakdown by raindrop impact and physico–chemical dispersion) are defined. Their relative importance depends on the nature of the rain, as well as on the soil's physical and chemical properties. The relations between aggregate breakdown, crusting and water erosion are analysed, and existing methods for the assessment of aggregate stability are reviewed. A unified framework for the measurement of aggregate stability is proposed to assess a soil's susceptibility to crusting and erosion. It combines three treatments having various wetting conditions and energies (fast wetting, slow wetting, and stirring after pre-wetting) and measures the resulting fragment size distribution after each treatment. It is designed to compare different soils, or different climatic conditions for a given soil, not to compare time-dependent changes in that soil.read more
Citations
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Journal ArticleDOI
Role of a cyanobacterial cover on structural stability of sandy soils in the Sahelian part of western Niger
TL;DR: In this article, the structural stability of these soils by testing aggregate breakdown under fastwetting, slow-wetting and mechanical breakdown was investigated, which revealed the great stability of aggregates from soils with a cyanobacterial cover (MWD 1.82 to 3.10 mm).
Journal ArticleDOI
Land degradation impact on soil organic carbon and nitrogen stocks of sub-tropical humid grasslands in South Africa
TL;DR: In this article, a degraded grassland showing an aerial cover gradient from 100% (Cov100, corresponding to a non-degraded grassland) to 50-75%, 25-50% and 0-5% was selected in South Africa.
Journal ArticleDOI
Evaluation of soil aggregate microstructure and stability under wetting and drying cycles in two Ultisols using synchrotron-based X-ray micro-computed tomography
TL;DR: In this article, the effect of soil pore characteristics on wet aggregate stability and aggregate tensile strength was evaluated using synchrotron-based X-ray micro-computed tomography (SR-mu CT) under wetting and drying cycles.
Journal ArticleDOI
The effect of straw and wood gasification biochar on carbon sequestration, selected soil fertility indicators and functional groups in soil: An incubation study
Veronika Hansen,Dorette Sophie Müller-Stöver,Lars J. Munkholm,Clément Peltre,Henrik Hauggaard-Nielsen,Lars Stoumann Jensen +5 more
TL;DR: In this paper, the effect of straw removal and gasification biochar (GB) addition on soil biological, chemical and physical properties in a 22-months soil incubation study with a temperate sandy loam soil was investigated.
Journal ArticleDOI
Effects of the inoculation of cyanobacteria on the microstructure and the structural stability of a tropical soil
Oumarou Malam Issa,Christian Défarge,Yves Le Bissonnais,Béatrice Marin,Odile Duval,Ary Bruand,L. P. D’Acqui,Sophie Nordenberg,Marcus Annerman +8 more
TL;DR: New data is presented demonstrating the improvement of soil physical quality in a few weeks after cyanobacteria inoculation, likely related to the changes induced in micromorphological characteristics by cyanobacterial filaments and EPS.
References
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Journal ArticleDOI
Organic matter and water-stable aggregates in soils
Judith. Tisdall,J.M. Oades +1 more
TL;DR: In this article, the effectiveness of various binding agents at different stages in the structural organization of aggregates is described and forms the basis of a model which illustrates the architecture of an aggregate.
Journal ArticleDOI
Aggregate structure and carbon, nitrogen, and phosphorus in native and cultivated soils
TL;DR: In this article, the macroaggregate-micraggregate conceptual model is applied to help explain accumulation of soil organic matter under native conditions and its loss upon cultivation in North American grassland soils.
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A Direct Method of Aggregate Analysis of Soils and a Study of the Physical Nature of Erosion Losses1
TL;DR: The physical nature of the erosion process was studied on carefully controlled field plats of Cecil clay located on several slopes, and losses from this strongly aggregated soil occurred primarily in the form of water stable aggregates.
Journal ArticleDOI
Aggregate hierarchy in soils
J.M. Oades,A.G. Waters +1 more
TL;DR: In this article, a range of disaggregating treatments from gentle to vigorous were applied to different particle sizes and the results indicated the potential role of roots and hyphae in the stabilization of larger aggregates, and for fragments of roots as nuclei for smaller aggregates.
Journal ArticleDOI
The relation of raindrop-size to intensity
J. Otis Laws,Donald A. Parsons +1 more
TL;DR: The applicability of such results to conditions of natural rainfall has been thrown in doubt as discussed by the authors, and the results have been found to be affected by the drop-size and velocity of the artificial rains applied.