ca20 {geoR} | R Documentation

## Calcium 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(ca20)

### Format

The object `ca20` belongs to the class `geodata` and is a list with the following elements:

`coords`
  a matrix with the coordinates of the soil samples.
`data`
  calcium content measured in mmol_c/dm^3.
`covariate`
  a data-frame with the covariates
  `altitude`
    a vector with the elevation of each sampling location, in meters (m).
  `area`
    a factor indicating the sub area to which the locations belongs.
`borders`
  a matrix with the coordinates defining the borders of the area.
`reg1`
  a matrix with the coordinates of the limits of the sub-area 1.
`reg1`
  a matrix with the coordinates of the limits of the sub-area 2.
`reg1`
  a matrix with the coordinates of the limits of the sub-area 3.

### 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.

### References

Oliveira, M.C.N. (2003) M'etodos de estimac{c}~ao de par^ametros em modelos geoestat'{i}sticos com diferentes estruturas de covari^ancias: uma aplicac{c}~ao ao teor de c'alcio no solo. Tese de Doutorado, ESALQ/USP/Brasil.

Further information on the package geoR can be found at:
http://www.est.ufpr.br/geoR.

[Package geoR version 1.5-7 Index]