camg {geoR} | R Documentation

## Calcium and magnesium content in soil samples

### Description

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.

### Usage

    data(camg)

### Format

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

east
  east-west coordinates, in meters.
north
  north-south coordinates, in meters.
elevation
  elevation, in meters
region
  a factor where numbers indicate different sub-regions within the area
ca020
  calcium content in the 0-20cm soil layer, measured in mmol_c/dm^3.
mg020
  calcium content in the 0-20cm soil layer, measured in mmol_c/dm^3.
ctc020
  calcium content in the 0-20cm soil layer.
ca2040
  calcium content in the 20-40cm soil layer, measured in mmol_c/dm^3.
mg2040
  calcium content in the 20-40cm soil layer, measured in mmol_c/dm^3.
ctc2040
  calcium content in the 20-40cm soil layer.

### Details

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

### Source

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) Caracterização pedológica da fazenda Angra - PESAGRO/RIO - Estação experimental de Campos (RJ). (compact disc). In: Congresso BRASILEIRO de Ciência do Solo. 26., Informação, globalização, uso do solo; Rio de Janeiro, 1997. trabalhos. Rio de Janeiro: Embrapa/SBCS.

### Examples

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

[Package geoR version 1.6-19 Index]