@article{fdi:010084066,
  title = {{C}omposition, fabric, and porosity of an arenic haplustalf of northeast {T}hailand : relation to penetration resistance},
  author = {{B}ruand, {A}. and {H}artmann, {C}hristian and {R}atana-{A}nupap, {S}. and {S}indhusen, {P}. and {P}oss, {R}oland and {H}ardy, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}andy uplands of northeast {T}hailand have subsoils with high resistance to root penetration that varies even though there is no variation in bulk density ({D}b). {T}he objective of this study was to determine how the resistance to penetration in these soils is related to the size, mineralogy, and arrangement of the elementary particles. {W}e studied the tilled topsoil ({A}p horizon), upper subsoil ({E} horizon), and lower subsoil ({B}t horizon) of an {A}renic {H}aplustalf. {R}esults showed similar skeleton grain-size distribution in the three horizons. {R}esults also showed similar {D}b in the {E} and {B}t horizons, and higher resistance to penetration in the {E} horizon. {D}ispersion of the material indicated the absence of a cementing agent between elementary particles. {T}he <2-?m fraction content was 37, 53, and 88 g kg-1 in the {A}p, {E}, and {B}t horizons, respectively, and that fraction was about one-third quartz. {T}he clay minerals were kaolinite with a small amount of swelling 2:1 clays in the {A}p and {B}t horizons. {M}ercury porosimetry and scanning electron microscopy ({SEM}) showed a closer arrangement of the sand resulting in less interparticle porosity in the {E} horizon than in the {B}t horizon. {T}he smaller interparticle porosity in the {E} horizon was compensated for by greater macroporosity resulting from biological activity, thus explaining the similar {D}b in the {E} and {B}t horizons. {D}espite similar {D}b, the greater penetration resistance in the {E} horizon results from a close packing of sand particles that restricts the displacement of soil particles during penetration by probe or roots.},
  keywords = {{THAILANDE}},
  booktitle = {},
  journal = {{S}oil {S}cience {S}ociety of {A}merica {J}ournal},
  volume = {68},
  numero = {1},
  pages = {185--193},
  ISSN = {0361-5995},
  year = {2004},
  DOI = {10.2136/sssaj2004.1850},
  URL = {https://www.documentation.ird.fr/hor/fdi:010084066},
}