oxford                 package:gstat                 R Documentation

_O_x_f_o_r_d _s_o_i_l _s_a_m_p_l_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     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).

_U_s_a_g_e:

     data(oxford)

_F_o_r_m_a_t:

     This data frame contains the following columns:

     _P_R_O_F_I_L_E profile number

     _X_C_O_O_R_D x-coordinate, field, non-projected

     _Y_C_O_O_R_D y-coordinate, field, non-projected

     _E_L_E_V elevation, m.

     _P_R_O_F_C_L_A_S_S soil class, obtained by classifying the soil profile at
          the sample site 

     _M_A_P_C_L_A_S_S soil class, obtained by looking up the site location in
          the soil map

     _V_A_L_1 Munsell colour component VALUE, 0-20 cm

     _C_H_R_1 Munsell colour component CHROMA, 20-40 cm

     _L_I_M_E_1 Lime content (tested using HCl), 0-20 cm

     _V_A_L_2 Munsell colour component VALUE, 0-20 cm

     _C_H_R_2 Munsell colour component CHROMA, 20-40 cm

     _L_I_M_E_2 Lime content (tested using HCl), 20-40 cm

     _D_E_P_T_H_C_M soil depth, cm 

     _D_E_P_2_L_I_M_E depth to lime, cm 

     _P_C_L_A_Y_1 percentage clay, 0-20 cm

     _P_C_L_A_Y_2 percentage clay, 20-40 cm

     _M_G_1 Magnesium content (ppm), 0-20 cm

     _O_M_1 organic matter (%), 0-20 cm

     _C_E_C_1 CES as mequ/100g air dry soil, 0-20 cm

     _P_H_1 pH, 0-20 cm

     _P_H_O_S_1 Phosphorous, 0-20 cm, ppm

     _P_O_T_1 K (potassium), 0-20 cm, ppm

_N_o_t_e:

     'oxford.jpg', in the gstat package data directory, shows an image
     of the soil map for the region

_R_e_f_e_r_e_n_c_e_s:

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

_E_x_a_m_p_l_e_s:

     data(oxford)
     summary(oxford)

