oxford: Oxford soil samples

Description Usage Format Note Author(s) References Examples

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

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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

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

Example output

    PROFILE           XCOORD        YCOORD          ELEV       PROFCLASS
 Min.   :  1.00   Min.   :100   Min.   : 100   Min.   :540.0   Cr:19    
 1st Qu.: 32.25   1st Qu.:200   1st Qu.: 600   1st Qu.:558.0   Ct:36    
 Median : 63.50   Median :350   Median :1100   Median :573.0   Ia:71    
 Mean   : 63.50   Mean   :350   Mean   :1100   Mean   :573.6            
 3rd Qu.: 94.75   3rd Qu.:500   3rd Qu.:1600   3rd Qu.:584.5            
 Max.   :126.00   Max.   :600   Max.   :2100   Max.   :632.0            
 MAPCLASS      VAL1            CHR1           LIME1            VAL2     
 Cr:31    Min.   :2.000   Min.   :1.000   Min.   :0.000   Min.   :4.00  
 Ct:36    1st Qu.:3.000   1st Qu.:2.000   1st Qu.:1.000   1st Qu.:4.00  
 Ia:59    Median :4.000   Median :2.000   Median :4.000   Median :8.00  
          Mean   :3.508   Mean   :2.468   Mean   :2.643   Mean   :6.23  
          3rd Qu.:4.000   3rd Qu.:3.000   3rd Qu.:4.000   3rd Qu.:8.00  
          Max.   :4.000   Max.   :4.000   Max.   :4.000   Max.   :8.00  
      CHR2       LIME2          DEPTHCM         DEP2LIME         PCLAY1     
 Min.   :2   Min.   :0.000   Min.   :10.00   Min.   :20.00   Min.   :10.00  
 1st Qu.:2   1st Qu.:4.000   1st Qu.:25.00   1st Qu.:20.00   1st Qu.:20.00  
 Median :2   Median :5.000   Median :36.00   Median :20.00   Median :24.50  
 Mean   :3   Mean   :3.889   Mean   :46.25   Mean   :30.32   Mean   :24.44  
 3rd Qu.:4   3rd Qu.:5.000   3rd Qu.:64.75   3rd Qu.:40.00   3rd Qu.:28.00  
 Max.   :6   Max.   :5.000   Max.   :91.00   Max.   :90.00   Max.   :37.00  
     PCLAY2           MG1              OM1              CEC1      
 Min.   :10.00   Min.   : 19.00   Min.   : 2.600   Min.   : 7.00  
 1st Qu.:10.00   1st Qu.: 44.00   1st Qu.: 4.100   1st Qu.:12.00  
 Median :10.00   Median : 72.00   Median : 5.350   Median :15.00  
 Mean   :14.76   Mean   : 93.53   Mean   : 5.995   Mean   :18.88  
 3rd Qu.:20.00   3rd Qu.:123.25   3rd Qu.: 7.175   3rd Qu.:25.25  
 Max.   :40.00   Max.   :308.00   Max.   :13.100   Max.   :43.00  
      PH1            PHOS1             POT1      
 Min.   :4.200   Min.   : 1.700   Min.   : 83.0  
 1st Qu.:7.200   1st Qu.: 6.200   1st Qu.:127.0  
 Median :7.500   Median : 8.500   Median :164.0  
 Mean   :7.152   Mean   : 8.752   Mean   :181.7  
 3rd Qu.:7.600   3rd Qu.:10.500   3rd Qu.:194.8  
 Max.   :7.700   Max.   :25.000   Max.   :847.0  
[1] "/usr/lib/R/site-library/gstat/external/oxford.jpg"

gstat documentation built on March 19, 2021, 9:06 a.m.