biomassc: Measuring soil microbial biomass

In smbdata: Data from "Statistical Methods in Biology"

Measuring soil microbial biomass

Description

An experiment was conducted to investigate the effects of procedural modifications on measurements of soil microbial biomass carbon, expressed as mg C per kg of soil. The study employed a 2 × 3 × 2 factorial design, testing two sieve sizes, three sample weights, and two shaking times, resulting in 12 distinct treatment combinations. Each combination was replicated four times in a completely randomized design. The response variable recorded was the amount of microbial carbon biomass (C). The purpose of the analysis is to quantify the main effects and possible interactions among sieve size, sample weight, and shaking time, as well as to determine whether any of the alternative procedures yield results within 10

Usage

biomassc

Format

A data frame with 5 variables: DSample, Size, Weight, Time, C.

DSample

Factor. Experimental unit identifier, representing the replicate number.

Size

Factor. Sieve size used for processing soil samples ("Small" or "Large").

Weight

Integer. Sample weight used in the protocol.

Time

Integer. Duration in minutes of shaking during sample processing.

C

Integer. Microbial biomass carbon in soil, measured as mg C per kg soil.

Source

Welham, S. J., Gezan, S. A., Clark, S. J., and Mead, A. (2015) Statistical Methods in Biology: Design and analysis of experiments and regression

Examples

fit <- lm(C ~ Size * Weight * Time,
          data = biomassc |>
             transform(Weight = factor(Weight),
                       Time = factor(Time)))
anova(fit)

smbdata documentation built on Jan. 20, 2026, 5:06 p.m.