agridat (version 1.8.1)

waynick.soil: Soil nitrogen and carbon in two fields

Description

Soil nitrogen and carbon in two fields

source

Waynick, Dean, and Sharp, Leslie. (1918). Variability in soils and its significance to past and future soil investigations, I-II. University of California press. http://archive.org/details/variabilityinsoi45wayn

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

dat <- waynick.soil

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

# Spatial plot
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 = "Davis field - nitrogen",
       col.regions =  bpy.colors(8), key.space = "right")

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