Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile

Shear strength of aggregates and the bulk soil matrix in two Haploxeroll of central Chile was assessed in order to determine: (1) the effect of previous tillage on shear parameters between aggregates and in the soil matrix and (2) the effects of structure development on differences between dry-wet m...

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Autores principales: Fuentes,I, Seguel,O, Casanova,M
Lenguaje:English
Publicado: Chilean Society of Soil Science / Sociedad Chilena de la Ciencia del Suelo 2013
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Acceso en línea:http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400005
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spelling oai:scielo:S0718-951620130004000052014-01-29Shear strength of aggregates compared with bulk soil of two haploxerolls from ChileFuentes,ISeguel,OCasanova,M Shear test cohesion internal friction angle soil structure Shear strength of aggregates and the bulk soil matrix in two Haploxeroll of central Chile was assessed in order to determine: (1) the effect of previous tillage on shear parameters between aggregates and in the soil matrix and (2) the effects of structure development on differences between dry-wet mechanical parameters. Undisturbed soil cylinders and single aggregates (0-10 cm layer) were collected from untilled and conventionally tilled sites in the Santiago (STG) and Mapocho Soil Series (MPC). General soil properties and shear parameters were determined. The shear tests were conducted on confined and free-draining aggregates and on soil cores, equilibrated at field capacity and air-dried, to obtain data on cohesion and angle of internal friction in the samples. Dry aggregates from the tilled sites showed 40 and 70% greater cohesion compared to untilled sites in STG and MPC soils, respectively, associated with a decrease in coarse porosity in the STG soil and a decrease in organic matter in the MPC soil, thus reducing its friability. In air-dried condition, aggregates from untilled sites developed 6-7 fold strength compared with soil matrix and the difference increased (9-13 fold) in samples from tilled sites. Undisturbed soil cores showed higher friction values when air-dried (68° in average, compared with 43° in individual aggregates), but at -33kPa water tension the tendency was reversed. The results of this study confirm that smaller differences between wet and dry behaviour are associated with better structural development and lower tillage intensity.info:eu-repo/semantics/openAccessChilean Society of Soil Science / Sociedad Chilena de la Ciencia del SueloJournal of soil science and plant nutrition v.13 n.4 20132013-12-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400005en10.4067/S0718-95162013005000065
institution Scielo Chile
collection Scielo Chile
language English
topic Shear test
cohesion
internal friction angle
soil structure
spellingShingle Shear test
cohesion
internal friction angle
soil structure
Fuentes,I
Seguel,O
Casanova,M
Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile
description Shear strength of aggregates and the bulk soil matrix in two Haploxeroll of central Chile was assessed in order to determine: (1) the effect of previous tillage on shear parameters between aggregates and in the soil matrix and (2) the effects of structure development on differences between dry-wet mechanical parameters. Undisturbed soil cylinders and single aggregates (0-10 cm layer) were collected from untilled and conventionally tilled sites in the Santiago (STG) and Mapocho Soil Series (MPC). General soil properties and shear parameters were determined. The shear tests were conducted on confined and free-draining aggregates and on soil cores, equilibrated at field capacity and air-dried, to obtain data on cohesion and angle of internal friction in the samples. Dry aggregates from the tilled sites showed 40 and 70% greater cohesion compared to untilled sites in STG and MPC soils, respectively, associated with a decrease in coarse porosity in the STG soil and a decrease in organic matter in the MPC soil, thus reducing its friability. In air-dried condition, aggregates from untilled sites developed 6-7 fold strength compared with soil matrix and the difference increased (9-13 fold) in samples from tilled sites. Undisturbed soil cores showed higher friction values when air-dried (68° in average, compared with 43° in individual aggregates), but at -33kPa water tension the tendency was reversed. The results of this study confirm that smaller differences between wet and dry behaviour are associated with better structural development and lower tillage intensity.
author Fuentes,I
Seguel,O
Casanova,M
author_facet Fuentes,I
Seguel,O
Casanova,M
author_sort Fuentes,I
title Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile
title_short Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile
title_full Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile
title_fullStr Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile
title_full_unstemmed Shear strength of aggregates compared with bulk soil of two haploxerolls from Chile
title_sort shear strength of aggregates compared with bulk soil of two haploxerolls from chile
publisher Chilean Society of Soil Science / Sociedad Chilena de la Ciencia del Suelo
publishDate 2013
url http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-95162013000400005
work_keys_str_mv AT fuentesi shearstrengthofaggregatescomparedwithbulksoiloftwohaploxerollsfromchile
AT seguelo shearstrengthofaggregatescomparedwithbulksoiloftwohaploxerollsfromchile
AT casanovam shearstrengthofaggregatescomparedwithbulksoiloftwohaploxerollsfromchile
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