biomass: Biomass Production in the Cape Fear Estuary
In VisCollin: Visualizing Collinearity Diagnostics

biomass

R Documentation

Biomass Production in the Cape Fear Estuary

Description

Data collected by Rick Linthurst (1979) at North Carolina State University for the purpose of identifying the important soil characteristics influencing aerial biomass production of the marsh grass Spartina alterniflora in the Cape Fear Estuary of North Carolina. Three types of Spartina vegetation areas (devegetated “dead” areas, “short” Spartina areas, and “tall” Spartina areas) were sampled in each of three locations (Oak Island, Smith Island, and Snows Marsh)

Samples of the soil substrate from 5 random sites within each location–vegetation type (giving 45 total samples) were analyzed for 14 soil physico-chemical characteristics each month for several months.

Format

A data frame with 45 observations on the following 17 variables.

loc: location, a factor with levels OI SI SM
type: area type, a factor with levels DVEG SHRT TALL
biomass: aerial biomass in gm^{-2}, a numeric vector
H2S: hydrogen sulfide ppm, a numeric vector
sal: percent salinity, a numeric vector
Eh7: ester-hydrolase, a numeric vector
pH: acidity as measured in water, a numeric vector
buf: a numeric vector
P: phosphorus ppm, a numeric vector
K: potassium ppm, a numeric vector
Ca: calcium ppm, a numeric vector
Mg: magnesium ppm, a numeric vector
Na: sodium ppm, a numeric vector
Mn: manganese ppm, a numeric vector
Zn: zinc ppm, a numeric vector
Cu: copper ppm, a numeric vector
NH4: ammonium ion ppm, a numeric vector

Source

Rawlings, J. O., Pantula, S. G., & Dickey, D. A. (2001). Applied Regression Analysis: A Research Tool, 2nd Ed., Springer New York. Table 5.1.

References

R. A. Linthurst. Aeration, nitrogen, pH and salinity as factors affecting Spartina Alterniflora growth and dieback. PhD thesis, North Carolina State University, 1979.

Examples

data(biomass)
str(biomass)
biomass.mod <- lm (biomass ~ H2S + sal + Eh7 + pH + buf + P + K + Ca + Mg + Na +
                           Mn + Zn + Cu + NH4,
                 data=biomass)
car::vif(biomass.mod)

(cd <- colldiag(biomass.mod, add.intercept=FALSE, center=TRUE))
# simplified display
print(cd, fuzz=.3)

VisCollin documentation built on Sept. 8, 2023, 5:58 p.m.