To cite soilDB in publications use:

Beaudette D, Skovlin J, Roecker S, Brown A (YYYY). soilDB: Soil Database Interface. R package version x.x.x, https://CRAN.R-project.org/package=soilDB.

Corresponding BibTeX entry:

  @Manual{,
    title = {soilDB: Soil Database Interface},
    author = {Dylan Beaudette and Jay Skovlin and Stephen Roecker and
      Andrew Brown},
    note = {R package version x.x.x},
    url = {https://CRAN.R-project.org/package=soilDB},
    year = {YYYY},
  }