R: Oxford soil samples

oxford {gstat} | R Documentation

## Oxford soil samples

### Description

Data: 126 soil augerings on a 100 x 100m square grid, with 6 columns and 21 rows. Grid is oriented with long axis North-north-west to South-south-east Origin of grid is South-south-east point, 100m outside grid.

Original data are part of a soil survey carried out by P.A. Burrough in 1967. The survey area is located on the chalk downlands on the Berkshire Downs in Oxfordshire, UK. Three soil profile units were recognised on the shallow Rendzina soils; these are Ia - very shallow, grey calcareous soils less than 40cm deep over chalk; Ct - shallow to moderately deep, grey-brown calcareous soils on calcareous colluvium, and Cr: deep, moderately acid, red-brown clayey soils. These soil profile classes were registered at every augering.

In addition, an independent landscape soil map was made by interpolating soil boundaries between these soil types, using information from the changes in landform. Because the soil varies over short distances, this field mapping caused some soil borings to receive a different classification from the classification based on the point data.

Also registered at each auger point were the site elevation (m), the depth to solid chalk rock (in cm) and the depth to lime in cm. Also, the percent clay content, the Munsell colour components of VALUE and CHROMA , and the lime content of the soil (as tested using HCl) were recorded for the top two soil layers (0-20cm and 20-40cm).

Samples of topsoil taken as a bulk sample within a circle of radius 2.5m around each sample point were used for the laboratory determination of Mg (ppm), OM1 %, CEC as mequ/100g air dry soil, pH, P as ppm and K (ppm).

### Usage

    data(oxford)

### Format

This data frame contains the following columns:

PROFILE

  profile number

XCOORD

  x-coordinate, field, non-projected

YCOORD

  y-coordinate, field, non-projected

ELEV

  elevation, m.

PROFCLASS

  soil class, obtained by classifying the soil profile at the sample site

MAPCLASS

  soil class, obtained by looking up the site location in the soil map

VAL1

  Munsell colour component VALUE, 0-20 cm

CHR1

  Munsell colour component CHROMA, 20-40 cm

LIME1

  Lime content (tested using HCl), 0-20 cm

VAL2

  Munsell colour component VALUE, 0-20 cm

CHR2

  Munsell colour component CHROMA, 20-40 cm

LIME2

  Lime content (tested using HCl), 20-40 cm

DEPTHCM

  soil depth, cm

DEP2LIME

  depth to lime, cm

PCLAY1

  percentage clay, 0-20 cm

PCLAY2

  percentage clay, 20-40 cm

MG1

  Magnesium content (ppm), 0-20 cm

OM1

  organic matter (%), 0-20 cm

CEC1

  CES as mequ/100g air dry soil, 0-20 cm

PH1

  pH, 0-20 cm

PHOS1

  Phosphorous, 0-20 cm, ppm

POT1

  K (potassium), 0-20 cm, ppm

### Note

`oxford.jpg`, in the gstat package external directory (see example below), shows an image of the soil map for the region

### Author(s)

P.A. Burrough; compiled for R by Edzer Pebesma

### References

P.A. Burrough, R.A. McDonnell, 1998. Principles of Geographical Information Systems. Oxford University Press.

### Examples

    data(oxford)
    summary(oxford)
    # open the following file with a jpg viewer:
    system.file("external/oxford.jpg", package="gstat")

[Package gstat version 2.0-3 Index]