Ion supply rates using ion-exchange resins.
Qian, P., J. J. Schoenau and N. Ziadi. 2008. Canadian Society of Soil Science
Abstract
Book Chapter from Soil sampling and methods of analysis 2
Sampling involves the selection from the total population of a subset of individuals upon
which measurements will be made; the measurements made on this subset (or sample) will
then be used to estimate the properties (or parameters) of the total population. Sampling is
inherent to any field research program in soil science because the measurement of the total
population is impossible for any realistic study. For example, even a single 10 ha field
contains about 100,000 1 m2 soil pits or 1X107 10 cm2 cores, and sampling of the entire
population would be more of an unnatural obsession than a scientific objective.
Sampling design involves the selection of the most efficient method for choosing
the samples that will be used to estimate the properties of the population. The definition
of the population to be sampled is central to the initial formulation of the research study
(Eberhardt and Thomas 1991; Pennock 2004). The sampling design defines how specific
elements will be selected from the population, and these sampled elements form the
sample population.
There are many highly detailed guides to specific sampling designs and the statistical
approaches appropriate for each design. The goal of this chapter is to present the issues
that should be considered when selecting an appropriate sampling design. In the final section,
specific design issues associated with particular research designs are covered. Suggested
readings are given in each section for more in-depth study on each topic
