Soil nitrogen and carbon in two fields
Soil nitrogen and carbon in two fields
A data frame with 200 observations on the following 6 variables.
fieldfield name, 2 levels
samplesample number
xx ordinate
yy ordinate
nitronitrogen content, percent
carboncarbon content, percent
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.
Waynick, Dean, and Sharp, Leslie. (1918). Variability in soils and its significance to past and future soil investigations, I-II. University of California press. https://archive.org/details/variabilityinsoi45wayn
## Not run:
library(agridat)
data(waynick.soil)
dat <- waynick.soil
# Strong relationship between N,C
libs(lattice)
xyplot(nitro~carbon|field, data=dat, main="waynick.soil")
# Spatial plot
libs(sp, 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
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.