Oxford soil samples
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).
data(oxford)
This data frame contains the following columns:
profile number
x-coordinate, field, non-projected
y-coordinate, field, non-projected
elevation, m.
soil class, obtained by classifying the soil profile at the sample site
soil class, obtained by looking up the site location in the soil map
Munsell colour component VALUE, 0-20 cm
Munsell colour component CHROMA, 20-40 cm
Lime content (tested using HCl), 0-20 cm
Munsell colour component VALUE, 0-20 cm
Munsell colour component CHROMA, 20-40 cm
Lime content (tested using HCl), 20-40 cm
soil depth, cm
depth to lime, cm
percentage clay, 0-20 cm
percentage clay, 20-40 cm
Magnesium content (ppm), 0-20 cm
organic matter (%), 0-20 cm
CES as mequ/100g air dry soil, 0-20 cm
pH, 0-20 cm
Phosphorous, 0-20 cm, ppm
K (potassium), 0-20 cm, ppm
oxford.jpg, in the gstat package external directory (see
example below), shows an image of the soil map for the region
P.A. Burrough; compiled for R by Edzer Pebesma
P.A. Burrough, R.A. McDonnell, 1998. Principles of Geographical Information Systems. Oxford University Press.
data(oxford)
summary(oxford)
# open the following file with a jpg viewer:
system.file("external/oxford.jpg", package="gstat")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.