ABSTRACT
Soil sampling for soil health assessment Skye Wills, Stephen Roecker and Candiss Williams, USDA-NRCS, USA; and Brian Murphy, Office of Environment and Heritage, Australia
1 Introduction
2 Defining objectives and generating hypotheses
3 Initial steps in designing a sampling plan
4 Sampling schemes: sample placement
5 Sampling sufficiency and compositing samples
6 Collecting the data
7 Metadata and implementation
8 Conclusions
9 Where to look for further information
10 Acknowledgements
11 References
Sampling for soil health should provide information on the properties and indicators of interest (such as those covered elsewhere in this book). There have been many papers and books that focus on the philosophy of soil quality and soil health and the indicators and properties that are associated with those concepts (Karlen et al., 2003; Palm et al., 2007; Harris and Romig, 2002; Carter, 2002; Gregorich, 2002; Doran and Parkin, 1994). This chapter focuses on the sampling portion of soil health assessment. Sampling is the process of collecting observations or measurements from a population, so that inferences can be made of the population. It is a critical step before any actual analysis can take place or conclusions can be drawn. A well-planned soil health sampling design will ensure that the resulting data are representative of the sample population and study objectives. Before developing a sampling design, it is important to consider the following phases of the research design:
1 Define objectives and generate hypotheses 2 Design sampling plan
3 Collect data 4 Analyse data: summarize, model and test (statistics) 5 Interprete results: evaluate, infer and project or/extrapolate 6 Action: draw conclusions and make recommendations.
