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")