agridat (version 1.16)

waynick.soil: Soil nitrogen and carbon in two fields

Description

Soil nitrogen and carbon in two fields

Format

A data frame with 200 observations on the following 6 variables.

field

field name, 2 levels

sample

sample number

x

x ordinate

y

y ordinate

nitro

nitrogen content, percent

carbon

carbon content, percent

Details

Two fields were studied, one at University Farm in Davis, the other near Oakley. The Davis field is silty clay loam, the Oakley field is blow sand.

Examples

# NOT RUN {
data(waynick.soil)
dat <- waynick.soil

# Strong relationship between N,C
require(lattice)
xyplot(nitro~carbon|field, data=dat, main="waynick.soil")

# Spatial plot
if(require(sp) & require(gstat)){
d1 <- subset(dat, field=="Davis")
d2 <- subset(dat, field=="Oakley")
coordinates(d1) <- data.frame(x=d1$x, y=d1$y)
coordinates(d2) <- data.frame(x=d2$x, y=d2$y)
spplot(d1, zcol = "nitro", cuts=8, cex = 1.6,
       main = "waynick.soil - Davis field - nitrogen",
       col.regions =  bpy.colors(8), key.space = "right")

# Variogram
v1 <- gstat::variogram(nitro~1, data=d1)
plot(v1, main="waynick.soil - Davis field - nitrogen") # Maybe hasn't reached sill
}

# }