Improving aggregate stability of sodic sandy loam soils by organics
The objective of this study was to examine at different application rates the effectiveness of some natural and synthetic organics in improving aggregate stability of sodic soils. An attempt has also been made by multi-index approach to select
Metropolitan agglomeration and sectoral aggregation
Proposition d'une méthode qui permet d'agréger des fonctions de production sectorielles à des fonctions métropolitaines en présence d'économies d'agglomération et d'échelle. Ces fonctions sont spécifiées et intégrées dans des modèles d'équilibre
Stability of clay aggregates as a function of water regimes in Impact of water and external forces on soil structure. Selected papers of the 1st Workshop on soilphysics and soilmechanics, Hannover 1986.
The experiments confirm the results that stability of clay aggregates is not only a matter of water content. Stability of clay aggregates is a function of their water regime, which is the result of the amount of water and the corresponding pressure.
The effects of spatial and locational cueing on the analysis of aggregate cognitive mapping data
Aggregation ; Cartographical display ; Cognitive process ; Locality ; Methodology ; United Kingdom
Les AA. évaluent les effets de la quantité d'information spatiale et du nombre de localités mentionnées sur les résultats agrégés de données de cartographie cognitive (représentation de connaissances spatiales). Il conviendrait d'adopter une analyse
Agrégation ; Critère de Theil ; Donnée ; Donnée agrégée ; Economie régionale ; Géographie humaine ; Information ; Méthodologie ; Perte d'information ; Théorie de l'information
Utilisation de la théorie de l'information à l'aménagement régional non pas à des matrices contenant des données manquantes mais à une matrice contenant des données agrégées établie à partir d'une matrice plus fine. La technique peut s'appliquer à
Aggregate clast form characteristics of deposits near the margins of four glaciers in the Jotunheimen Massif, Norway
Samples of clasts from deposits with different erosional histories near the margins of four Jotunheimen glaciers revealed systematic differences in their aggregate form characteristics. Samples of frost-shattered detritus generally contain many
slabby clasts (low c: a axis ratios) but samples from subglacial deposits and talus do not. The distinction is relatable to the spacing of dilation joints in the parent rock. The potential for employing systematic differences in aggregate clast form
Simple aggregation and disaggregation subject to minimal information loss and other criteria
The main purpose of this paper is to develop a method and an algorithm for the aggregation as well as disaggregation of n-way tables, thereby minimizing a set of suitable criteria. One should observe that there is no real difference between
aggregation and disaggregation when using this method. Here are presented some basic facts about a mainly one-dimensional method and an outline showing how the method may be extended to more complex cases.
Enhanced settling velocities and vertical transport of particulate matter by aggregation in the benthic boundary layer
The importance of aggregation processes in the benthic boundary layer (BBL) with regards to settling velocities and flux of organic carbon was investigated at 4 stations on a coastal-depositional area transect in the southwest Baltic Sea, between
1996 and 1998. A second focus point of the study is the comparison of vertical and horizontal transport of both aggregated and suspended material.
A study of the role of regionalization in the generation of aggregation error in regional input-output models
Aggregation ; Error ; Input-output model ; Model ; Multiplicator ; Regional economy ; Regionalization ; Statistics
De nombreux chercheurs en analyse régionale utilisent des modèles d'entrée-sortie agrégés à l'échelle nationale. Ils effectuent les ajustements des flux à cette échelle. Les AA. expliquent en quoi cette approche peut se révéler inadaptée. Ils
Improvements of water-stability of clay aggregates admixed with aqueous polymer soil stabilizers
Aggregate ; Applied geomorphology ; Clay ; Erosion control ; Experimentation ; Mass movement ; Microstructure ; Slope ; Soil erosion ; Soil properties ; Structural stability
Aqueous soil stabilizers improve soil properties. Water-stability of soil aggregates was determined using 2 different soil stabilizers : S-type and E-type. Various concentrations of the 2 soil stabilizers were tested in soil aggregates (5-10 mm
). Testing the aggregates using the static water-measure method showed that the water-satbility index, K, increased with the concentration of soil stabilizers. Two aggregate collapse models were found and discussed. Their pattern depends on the formation
of a membrane structure on the surface of the aggregates through physicochemical bonding.
of vegetation succession on total carbon (C), aggregate C, and intra-aggregate particulate organic matter-carbon (iPOM-C) concentrations. The coarse and fine iPOM-C concentrations exhibited different trends with vegetation restoration. In conclusion, vegetation
restoration caused an increase in small macroaggregates, enhancing the uniformity of the soil aggregate size distribution and inducing greater soil organic carbon sequestration.
Laser diffraction analysis of the disintegration of aeolian sedimentary aggregates in water
Aeolian features ; Aeolian transport ; Aggregate ; Grain size distribution ; Methodology ; Sediment transport ; Soil erosion ; Water erosion ; X-ray diffraction analysis
A new method for the analysis of aggregate disintegration in water was tested using aeolian sediment samples. Repeated laser diffraction analysis of a single sample circulating in deionized water provides a detailed view of the changes in particle
size distribution as aggregates disintegrate. This methodology also allows experiments on the effects of water chemistry, exchangeable cation chemistry, and prewetting. The results suggest that aggregates of widely varying stabilities can occur
in a wide range of particle size classes; that is, aggregate stability may to some extent be independent of the hierarchy of aggregate sizes emphasized in earlier research. The methods described here are applicable to a wide range of soils and sediments.
Effects of vegetation type on soil resistance to erosion: Relationship between aggregate stability and shear strength
Aggregate ; China ; Erosion control ; Human impact ; Landslide ; Soil erosion ; Soil properties ; Vegetation ; Water erosion
The AA. investigated the effect of vegetation on both soil aggregate stability and shear strength (through direct shear tests) in former croplands converted to vegetated erosion protection areas within the context of China's sloping land conversion
programme. Significant positive linear relationships were found between vegetation, soil aggregate stability and soil shear strength. Vegetation stabilised soil under different hierarchical levels of aggregate organisation, i.e. intra- and inter-aggregate
. As herbaceous vegetation was more efficient than trees in improving aggregate stability, it is suggested that mixtures of different plant functional types would improve soil conservation on slopes, by reducing both surface water erosion and shallow substrate