camg              package:geoR              R Documentation(latin1)

_C_a_l_c_i_u_m _a_n_d _m_a_g_n_e_s_i_u_m _c_o_n_t_e_n_t _i_n _s_o_i_l _s_a_m_p_l_e_s

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

     This data set contains the calcium content measured in soil
     samples taken from the 0-20cm layer at 178 locations within a
     certain study area divided in three sub-areas. The elevation at
     each location was also recorded.

     The first region is tipically flooded during the rain season and
     not used as an experimental area. The calcium levels would
     represent the natural content in the region. The second region has
     received fertilizers a while ago and is tipically occupied by rice
     fields. The third region has recieved fertilizers recently and is
     frequently used as an experimental area.

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

     data(camg)

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

     A data frame with 178 observations on the following 10 variables.

     _e_a_s_t east-west coordinates, in meters.

     _n_o_r_t_h north-south coordinates, in meters.

     _e_l_e_v_a_t_i_o_n elevation, in meters

     _r_e_g_i_o_n a factor where numbers indicate different sub-regions
          within the area

     _c_a_0_2_0 calcium content in the 0-20cm soil layer, measured in
          mmol_c/dm^3.  

     _m_g_0_2_0 calcium content in the 0-20cm soil layer, measured in
          mmol_c/dm^3.  

     _c_t_c_0_2_0 calcium content in the 0-20cm soil layer.  

     _c_a_2_0_4_0 calcium content in the 20-40cm soil layer, measured in
          mmol_c/dm^3.  

     _m_g_2_0_4_0 calcium content in the 20-40cm soil layer, measured in
          mmol_c/dm^3.  

     _c_t_c_2_0_4_0 calcium content in the 20-40cm soil layer.  

_D_e_t_a_i_l_s:

     More details about this data-set, including coordinates of the
     region and sub-region borders can be found in the data object
     'ca20'.

_S_o_u_r_c_e:

     The data was collected by researchers from PESAGRO and
     EMBRAPA-Solos, Rio de Janeiro, Brasil and provided by Dra. Maria
     Cristina Neves de Oliveira.

     Capeche, C.L.; Macedo, J.R.; Manzatto, H.R.H.; Silva, E.F. (1997)
     Caracterizao pedolgica da fazenda Angra - PESAGRO/RIO - Estao
     experimental de Campos (RJ). (compact disc). In: Congresso
     BRASILEIRO de Cincia do Solo. 26., Informao, globalizao, uso
     do solo; Rio de Janeiro, 1997. trabalhos. Rio de Janeiro:
     Embrapa/SBCS.

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

     plot(camg[-(1:2),])
     mg20 <- as.geodata(camg, data.col=6)
     plot(mg20)
     points(mg20)

