Look up siblings and cousins for a given soil series from the current fiscal year SSURGO snapshot via SoilWeb.

The siblings of any given soil series are defined as those soil components (major and minor) that share a parent map unit with the named series (as a major component). Component names are filtered using a snapshot of the Soil Classification database to ensure that only valid soil series names are included. Cousins are siblings of siblings. Data are sourced from SoilWeb which maintains a copy of the current SSURGO snapshot. Visualizations of soil "siblings"-related concepts can be found in the "Sibling Summary" tab of Soil Data Explorer app: https://casoilresource.lawr.ucdavis.edu/sde/.

Additional resources:

siblings(s, only.major = FALSE, component.data = FALSE, cousins = FALSE)



character vector, the name of a single soil series, case-insensitive.


logical, should only return siblings that are major components


logical, should component data for siblings (and optionally cousins) be returned?


logical, should siblings-of-siblings (cousins) be returned?


A list containing:

  • sib: data.frame containing siblings, major component flag, and number of co-occurrences

  • sib.data: data.frame containing sibling component data (only when component.data = TRUE)

  • cousins: data.frame containing cousins, major component flag, and number of co-occurrences (only when cousins = TRUE)

  • cousin.data: data.frame containing cousin component data (only when cousins = TRUE, component.data = TRUE)


O'Geen, A., Walkinshaw, M. and Beaudette, D. (2017), SoilWeb: A Multifaceted Interface to Soil Survey Information. Soil Science Society of America Journal, 81: 853-862. doi:10.2136/sssaj2016.11.0386n

See also

OSDquery, siblings, fetchOSD


D.E. Beaudette


# \donttest{
if(requireNamespace("curl") &
    curl::has_internet()) {
    # basic usage
    x <- siblings('zook')
    # restrict to siblings that are major components
    # e.g. the most likely siblings
    x <- siblings('zook', only.major = TRUE)
#>    series      sibling majcompflag  n
#> 1    zook       Olmitz        TRUE 17
#> 2    zook        Vigar        TRUE 12
#> 3    zook       Vesser        TRUE 10
#> 4    zook          Ely        TRUE 10
#> 5    zook      Excello        TRUE  9
#> 6    zook         Colo        TRUE  8
#> 7    zook      Nodaway        TRUE  5
#> 8    zook          Zoe        TRUE  3
#> 9    zook Mt. Sterling        TRUE  3
#> 10   zook        Kezan        TRUE  2
#> 11   zook        Clamo        TRUE  2
#> 12   zook     Humeston        TRUE  1
#> 13   zook         Klum        TRUE  1
#> 14   zook       Quiver        TRUE  1
# }