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 typically 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 fertilisers a while ago and is typically occupied by rice fields. The third region has received fertilisers recently and is frequently used as an experimental area.
data(ca20)The object ca20 belongs to the class geodata
and is a list
with the following elements:
coordsa matrix with the coordinates of the soil samples.
datacalcium content measured in \(mmol_c/dm^3\).
covariatea data-frame with the covariates
altitudea vector with the elevation of each sampling location, in meters (\(m\)).
areaa factor indicating the sub area to which the locations belongs.
bordersa matrix with the coordinates defining the borders of the area.
reg1a matrix with the coordinates of the limits of the sub-area 1.
reg1a matrix with the coordinates of the limits of the sub-area 2.
reg1a matrix with the coordinates of the limits of the sub-area 3.
Oliveira, M.C.N. (2003) M<e9>todos de estima<e7><e3>o de par<e2>metros em modelos geoestat<ed>sticos com diferentes estruturas de covari<e2>ncias: uma aplica<e7><e3>o ao teor de c<e1>lcio no solo. Tese de Doutorado, ESALQ/USP/Brasil.
Further information on the package geoR can be found at: http://www.leg.ufpr.br/geoR.