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Search Results: 1 - 10 of 712 matches for " Dorota Dec "
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LA PERMEABILIDAD DEL AIRE Y CONDUCTIVIDAD HIDRáULICA SATURADA COMO HERRAMIENTA PARA LA CARACTERIZACIóN FUNCIONAL DE LOS POROS DEL SUELO
Dorner,José; Dec,Dorota;
Revista de la ciencia del suelo y nutrición vegetal , 2007, DOI: 10.4067/S0718-27912007000200001
Abstract: in order to describe the pore functions of ploughed soils, undisturbed soil samples were collected at two depths and orientations (vertical and horizontal) in structured soils in the weichselian moraine region in northern germany. the water retention curve, air permeability (ka) and saturated hydraulic conductivity (kf) were measured. the pore-size distribution, air-filled porosities and pore continuity indices were calculated. the tillage affects the soil quantitatively and qualitatively. the tillage-induced ploughed pan not only implies a reduction of the pore volume but also causes a direction-dependent behaviour of hydraulic properties through the development of a platy structure. in order to assess these qualitative changes, measurements like ka and/or kf are a good tool to describe the physical quality of a soil
LA PERMEABILIDAD DEL AIRE Y CONDUCTIVIDAD HIDRáULICA SATURADA COMO HERRAMIENTA PARA LA CARACTERIZACIóN FUNCIONAL DE LOS POROS DEL SUELO Air permeability and saturated hydraulic conductivity as a tool for the functional characterization of soil pores
José Dorner,Dorota Dec
Revista de la Ciencia del Suelo y Nutrición Vegetal , 2007,
Abstract: Con el objetivo de describir los aspectos funcionales de los poros de suelos labrados, se recolectaron muestras no disturbadas en dos profundidades y orientaciones (vertical y horizontal) en suelos estructurados del Norte de Alemania. Se determinó la curva de retención de agua, la permeabilidad de aire (ka) y la conductividad hidráulica en fase saturada (k f). Se calculó la distribución de poros por tama o, la porosidad de aire e índices de continuidad de poros. El manejo agrícola afecta al suelo cuantitativa y cualitativamente. La formación de un pie de arado implica no tan sólo una reducción del volumen de poros sino que también causa una dependencia espacial de las propiedades hidráulicas del suelo a través de la formación de una estructura laminar. Con el objeto de establecer dichos cambios cualitativos, mediciones como ka y k f son una buena herramienta para describir la calidad física del suelo In order to describe the pore functions of ploughed soils, undisturbed soil samples were collected at two depths and orientations (vertical and horizontal) in structured soils in the Weichselian moraine region in Northern Germany. The water retention curve, air permeability (ka) and saturated hydraulic conductivity (k f) were measured. The pore-size distribution, air-filled porosities and pore continuity indices were calculated. The tillage affects the soil quantitatively and qualitatively. The tillage-induced ploughed pan not only implies a reduction of the pore volume but also causes a direction-dependent behaviour of hydraulic properties through the development of a platy structure. In order to assess these qualitative changes, measurements like ka and/or k f are a good tool to describe the physical quality of a soil
Temporal and spatial variability of structure dependent properties of a volcanic ash soil under pasture in southern Chile
Dec,Dorota; D?rner,José; Balocchi,Oscar;
Chilean journal of agricultural research , 2011, DOI: 10.4067/S0718-58392011000200015
Abstract: prairies are a main source for livestock feeding in southern chile. the aim of this research was to define how grazing events and natural wetting and drying cycles (wd) affect the spatial and temporal variability of the soil?s structural properties. the investigation was conducted in a duric hapludand, valdivia series. penetration resistance (pr) and volumetric water content (wc), measured in situ, were used to prepare maps which show i) temporal (1383 to 3047 kpa for 46 to 16% wc) and spatial changes, and ii) grazing events as an important factor influencing spatial changes in pr (differences of 3421 kpa between max and min values). grazing and wd cycles induced changes in the soil?s mechanical stability and pore functions, which indicate that structure-dependent properties are dynamic. during the study, variations between 0.3 and 0.9 log μm2 were detected for air permeability (ka), whereas air capacity (acp) ranged between 5 and 18%. soil mechanical strength also varied over time and showed changes in pr. the same instrument, however, cannot be used to identify changes in soil pore functions. generally, after grazing events, soil deformation induced a reduction of air capacity and permeability; however, after wd cycles, soil pores were able to recover their functional integrity.
EFFECT OF SOIL MANAGEMENT ON THEIR THERMAL PROPERTIES
Dec,Dorota; D?rner,José; Horn,Rainer;
Revista de la ciencia del suelo y nutrición vegetal , 2009, DOI: 10.4067/S0718-27912009000100003
Abstract: in order to determine the effect of soil management on its thermal properties, undisturbed soil samples were taken from two tillage treatments (conventional and conservation treatment) at two depths (0-30cm and 30-60cm) of a stagnic luvisol (silt loam) before and after directly wheeling. the experimental field, located in harste/goettingen, germany, was cultivated with sugar beet (beta vulgaris). to calculate thermal properties of the soil, the volumetric water content (tdr needles) and temperature (pt 100 thermistors) during the simulation of the daily fluctuation of temperature were registered in laboratory and then the thermal conductivity, volumetric heat capacity and heat diffusivity were calculated following the damping depth method and the statistical-physical model. the results showed that different tillage systems as well as compaction influenced soil thermal properties. conservational tillage treatment with more stable and better developed soil structure at a depth of 0-30cm (which represents ploughing depth and decides differences between soil management) presented higher water content as the main factor deciding soil thermal properties. according to this, values of thermal conductivity and volumetric heat capacity under this treatment were greater than under conventional. thermal diffusivity, however, was lower. from the latter we can conclude that under conservation tillage treatment the soil can store more heat, but at the same time and as a result of the lower thermal diffusivity, the atmospheric variations do not affect the soil thermal regime strongly.
EFFECT OF SOIL MANAGEMENT ON THEIR THERMAL PROPERTIES Efecto del manejo del suelo sobre sus propiedades térmicas
Dorota Dec,José D?rner,Rainer Horn
Revista de la Ciencia del Suelo y Nutrición Vegetal , 2009,
Abstract: In order to determine the effect of soil management on its thermal properties, undisturbed soil samples were taken from two tillage treatments (conventional and conservation treatment) at two depths (0-30cm and 30-60cm) of a Stagnic Luvisol (silt loam) before and after directly wheeling. The experimental field, located in Harste/Goettingen, Germany, was cultivated with sugar beet (Beta vulgaris). To calculate thermal properties of the soil, the volumetric water content (TDR needles) and temperature (pT 100 thermistors) during the simulation of the daily fluctuation of temperature were registered in laboratory and then the thermal conductivity, volumetric heat capacity and heat diffusivity were calculated following the damping depth method and the statistical-physical model. The results showed that different tillage systems as well as compaction influenced soil thermal properties. Conservational tillage treatment with more stable and better developed soil structure at a depth of 0-30cm (which represents ploughing depth and decides differences between soil management) presented higher water content as the main factor deciding soil thermal properties. According to this, values of thermal conductivity and volumetric heat capacity under this treatment were greater than under conventional. Thermal diffusivity, however, was lower. From the latter we can conclude that under conservation tillage treatment the soil can store more heat, but at the same time and as a result of the lower thermal diffusivity, the atmospheric variations do not affect the soil thermal regime strongly. Con el objetivo de determinar el efecto del manejo del suelo sobre sus propiedades térmicas, se recolectaron muestras no disturbadas de suelo desde dos tratamientos de cultivo (convencional y conservacionista) en dos profundidades (0-30cm y 30-60cm) de un Stagnic Luvisol (franco limoso) antes y después del tránsito de una cosechadora. El campo experimental, ubicado in Hartse/Goettingen, Alemania, fue cultivado con remolacha azucarera (Beta vulgaris). Para calcular las propiedades térmicas del suelo, se registró el contenido volumétrico de agua (TDRs) y la temperatura (thermistors pT100) durante la simulación de la fluctuación diaria de la temperatura en laboratorio. A partir de esa simulación, se calculó la conductividad térmica, la capacidad calórica y la difusión de calor de acuerdo al método "damping depth" y "statistical-physical model". Los resultados demuestran que tanto los diferentes tipos de manejo como también la compactación del suelo afectan sus propiedades térmicas. El manejo
Temporal and spatial variability of structure dependent properties of a volcanic ash soil under pasture in southern Chile Variaciones temporales y espaciales en las propiedades que dependen de estructura de un suelo derivado de cenizas volcánicas bajo pastoreo en el sur de Chile
Dorota Dec,José D?rner,Oscar Balocchi
Chilean Journal of Agricultural Research , 2011,
Abstract: Prairies are a main source for livestock feeding in southern Chile. The aim of this research was to define how grazing events and natural wetting and drying cycles (WD) affect the spatial and temporal variability of the soil’s structural properties. The investigation was conducted in a Duric Hapludand, Valdivia Series. Penetration resistance (PR) and volumetric water content (WC), measured in situ, were used to prepare maps which show i) temporal (1383 to 3047 kPa for 46 to 16% WC) and spatial changes, and ii) grazing events as an important factor influencing spatial changes in PR (differences of 3421 kPa between max and min values). Grazing and WD cycles induced changes in the soil’s mechanical stability and pore functions, which indicate that structure-dependent properties are dynamic. During the study, variations between 0.3 and 0.9 log μm2 were detected for air permeability (k a), whereas air capacity (ACp) ranged between 5 and 18%. Soil mechanical strength also varied over time and showed changes in PR. The same instrument, however, cannot be used to identify changes in soil pore functions. Generally, after grazing events, soil deformation induced a reduction of air capacity and permeability; however, after WD cycles, soil pores were able to recover their functional integrity. Las praderas son la principal fuente de alimentación del ganado en el sur de Chile. El objetivo de esta investigación fue definir cómo afectan los eventos de pastoreo y ciclos naturales de mojado y secado (WD), la variabilidad temporal y espacial de las propiedades estructurales del suelo. La investigación fue realizada en un Duric Hapludand, Serie Valdivia. La resistencia a la penetración (PR) y el contenido volumétrico de agua (WC) determinados in situ fueron usados para preparar mapas que muestran i) que ellas cambian en el tiempo (PR: 1383-3047 kPa para WC: 46-16%) y espacio, y ii) que los eventos de pastoreo son un factor importante que influye sobre la variación espacial de PR (diferencias de 3421 kPa entre los valores max y min). El pastoreo y WD inducen cambios en la estabilidad mecánica y la función de los poros indicando que las propiedades estructurales son dinámicas. En permeabilidad de aire (k a) se detectaron variaciones entre 0,3 y 0,9 log mm2 durante el período de estudio, mientras que la capacidad de aire osciló entre 5 y 18%. La estabilidad mecánica también varió en el tiempo reflejando los cambios en PR. Este instrumento, sin embargo, no puede ser usado para identificar variaciones en las funciones de los poros del suelo. Generalmente, después de los evento
EFECTO DEL CAMBIO DE USO EN LA ESTABILIDAD DE LA ESTRUCTURA Y LA FUNCIóN DE LOS POROS DE UN ANDISOL (TYPIC HAPLUDAND) DEL SUR DE CHILE
D?rner,José; Dec,Dorota; Peng,Xinhua; Horn,Rainer;
Revista de la ciencia del suelo y nutrición vegetal , 2009, DOI: 10.4067/S0718-27912009000300003
Abstract: volcanic soils in southern chile cover approximately 60% of the arable land in the country. these soils are under a wide range of land uses from pristine systems to intensively used ones. the objective of this study was to determine the effect of the land use change on: i) the structural stability after external and internal forces, ii) the hydraulic conductivity and iii) its functional resilience. disturbed and undisturbed soil samples were collected at 5, 20 and 40 cm depths in an andisol (typic hapludand) under native forest (nf), 50 year old pasture (p50) and 1 year old pasture (pi). the water retention, shrinkage and consolidation curves, hydraulic conductivity (ks), air permeability (ka), organic carbon content (co), soil texture and allophane contents were determined. the unsaturated hydraulic conductivity (ku) was estimated according to van genuchten (1980). soil deformation indexes as a consequence of mechanical (colem) and hydraulic (coleh) stresses were calculated. the studied soil is subject to continuous changes in their structure as a consequence of mechanical and hydraulic stresses affecting the pore size distribution and its functionality. the magnitude of these changes decreased with the increasing intensity of the land use. the great shrinkage capacity of the soil may have consequences on its hydraulic behaviour depending on the drying intensity through the formation of cracks and preferential path flows. finally, the soil pores are able to recover its functional integrity after compaction, which is strongly related to the presence of organic matter contents.
EFFECT OF BULK DENSITY ON HYDRAULIC PROPERTIES OF HOMOGENIZED AND STRUCTURED SOILS
Dec,Dorota; Dorner,José; Becker-Fazekas,Orsolya; Horn,Rainer;
Revista de la ciencia del suelo y nutrición vegetal , 2008, DOI: 10.4067/S0718-27912008000100001
Abstract: in order to determine the effect of bulk density and soil structure on their hydraulic behaviour, undisturbed samples were collected and disturbed samples were prepared from a luvisol. the experimental field, located in harste/goettingen, germany, was cultivated with sugar beet (beta vulgaris). the water retention curve (wrc) and saturated hydraulic conductivity (ks) were measured on undisturbed samples and homogenized samples prepared at different bulk densities (1.2 -1.4 and 1.6 mg m-3). to determine the effect of soil shrinkage on the unsaturated hydraulic conductivity (k/ψ) ,the vertical deformation of the repacked samples was measured and relative water content differences (dθ)were determined. the hydraulic properties of soils with identical texture depend on bulk density (db) and structure. the increasing bulk density not only induces changes in the pore-size distribution but also affects the ability of soil to shrink and to conduct water under unsaturated conditions. greater shrinkage was observed for samples with lower db as a consequence of reduction of coarse pores. the water content differences increase with decreasing bulk density, inducing an increasing error in the estimation of k/ψ
EFECTO DEL CAMBIO DE USO EN LA ESTABILIDAD DE LA ESTRUCTURA Y LA FUNCIóN DE LOS POROS DE UN ANDISOL (TYPIC HAPLUDAND) DEL SUR DE CHILE Effect of Land Use on Structural Stability and Pore Functions of an Andisol (Typic Hapludand) in Southern Chile
José D?rner,Dorota Dec,Xinhua Peng,Rainer Horn
Revista de la Ciencia del Suelo y Nutrición Vegetal , 2009,
Abstract: Los suelos volcánicos del sur de Chile constituyen cerca del 60% del suelo arable del país. Estos suelos se encuentran bajo un amplio rango de usos desde sistemas prístinos hasta otros con un uso intensivo. El objetivo de este trabajo fue determinar el efecto del cambio de uso de suelo sobre: i) la estabilidad del suelo frente a presiones externas e internas; ii) la conductividad hidráulica y iii) su resiliencia funcional. Muestras disturbadas y no disturbadas de suelo fueron recolectadas a 5, 20, 40 cm de profundidad en un suelo Andisol (Typic Hapludand) bajo un renoval de bosque nativo (NF), una pradera de 50 a os (P50) y otra de 1 a o de uso (Pl). Se determinó la curva de retención de agua, contracción y consolidación, la conductividad hidráulica saturada (Ks), permeabilidad de aire (Ka), contenidos de carbono orgánico (CO), textura y alofán. Se estimó la conductividad hidráulica no saturada (Ku) de acuerdo al modelo propuesto por van Genuchten (1980). Se definieron índices de deformación de suelo como consecuencia de estreses mecánicos (COELm) e hidráulicos (COELh). El suelo estudiado está sujeto a constantes cambios en su estructura como consecuencia de estreses mecánicos e hidráulicos afectando la distribución de los poros y su funcionalidad. La magnitud de estos cambios disminuye con el incremento de la intensidad de uso del suelo. La gran capacidad de contracción del suelo puede traer consecuencias en su comportamiento hidráulico dependiendo de la intensidad del secado a través de la formación de grietas y vías de flujo de preferencial. Finalmente, los poros del suelo son capaces de recuperar su integridad funcional después de una compactación, lo que está estrechamente relacionado con los contenidos de materia orgánica. Volcanic soils in southern Chile cover approximately 60% of the arable land in the country. These soils are under a wide range of land uses from pristine systems to intensively used ones. The objective of this study was to determine the effect of the land use change on: i) the structural stability after external and internal forces, ii) the hydraulic conductivity and iii) its functional resilience. Disturbed and undisturbed soil samples were collected at 5, 20 and 40 cm depths in an Andisol (Typic Hapludand) under native forest (NF), 50 year old pasture (P50) and 1 year old pasture (PI). The water retention, shrinkage and consolidation curves, hydraulic conductivity (Ks), air permeability (Ka), organic carbon content (CO), soil texture and allophane contents were determined. The unsaturated hydraulic conductivity (Ku) was estima
EFFECT OF BULK DENSITY ON HYDRAULIC PROPERTIES OF HOMOGENIZED AND STRUCTURED SOILS Efecto de la densidad aparente sobre las propiedades hidráulicas de los suelos homogenizados y estructurados
Dorota Dec,José Dorner,Orsolya Becker-Fazekas,Rainer Horn
Revista de la Ciencia del Suelo y Nutrición Vegetal , 2008,
Abstract: In order to determine the effect of bulk density and soil structure on their hydraulic behaviour, undisturbed samples were collected and disturbed samples were prepared from a Luvisol. The experimental field, located in Harste/Goettingen, Germany, was cultivated with sugar beet (Beta vulgaris). The water retention curve (WRC) and saturated hydraulic conductivity (Ks) were measured on undisturbed samples and homogenized samples prepared at different bulk densities (1.2 -1.4 and 1.6 Mg m-3). To determine the effect of soil shrinkage on the unsaturated hydraulic conductivity (k/Ψ) ,the vertical deformation of the repacked samples was measured and relative water content differences (dθ)were determined. The hydraulic properties of soils with identical texture depend on bulk density (dB) and structure. The increasing bulk density not only induces changes in the pore-size distribution but also affects the ability of soil to shrink and to conduct water under unsaturated conditions. Greater shrinkage was observed for samples with lower dB as a consequence of reduction of coarse pores. The water content differences increase with decreasing bulk density, inducing an increasing error in the estimation of k/Ψ Con el objetivo de determinar el efecto de la densidad aparente y estructura del suelo sobre su comportamiento hidráulico, muestras no disturbadas fueron recolectadas y muestras disturbadas fueron preparadas a partir de un Luvisol. El campo experimental, ubicado en Harste/Goettingen, Alemania, fue cultivado con remolacha (Beta vulgaris). La curva de retención de agua (WRC) y la conductividad hidráulica saturada (Ks) fue determinada en muestras no disturbadas de suelo y en muestras homogenizadas preparadas a distintas densidades aparentes (1.2 -1.4 y 1.6 Mg m-3). Para determinar el efecto de la contracción del suelo sobre la conductividad hidráulica no saturada (K/Ψ), se midió la deformación vertical de las muestras ensambladas y a partir de ello se determinó la diferencia en el contenido volumétrico de agua. Las propiedades hidráulicas de suelos con la misma textura dependen de la densidad aparente y la estructura. El incremento en la densidad aparente no sólo induce cambios en la distribución de la porosidad sino que también afecta la capacidad de contracción del suelo y de conducir agua en fase no saturada. Una mayor contracción fue observada en muestras con menor densidad aparente como consecuencia de la reducción de los poros gruesos. Las diferencias en el contenido de agua aumentan con una disminución en la densidad aparente, induciendo un mayor error en l
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