Most studies that use the stable isotope technique to infer the sources of plant water uptake rely on the extraction of water from soil and plant samples, such as soil cores, small wood cores, stems, branches, leaves, root collars or others.


In this section, we focus on the destructive sampling protocols to collect such samples. More specifically, we provide an overview of the collection of ancillary data and other measurements of plant physiological performance related to plant water uptake and of important aspects that need to be taken into account during sampling. Nondestructive sampling techniques that allow for direct in situ collection of liquid soil water are also reviewed. Recent advancements in laser-based spectroscopy have allowed for the development of continuous in situ measurements of the isotopic composition of plant- and soil-water vapor.