ISO 18400-101:2017 specifies the procedural elements to be taken in the preparation and application of a sampling plan. The sampling plan describes among other things what laboratory samples are to be taken, how they are to be taken and from where they are to be taken, in order that the objectives of the investigation programme can be achieved. The principles or basic rules outlined in this document provide a framework that can be used to- produce standardized sampling plans for use in more regular or routine circumstances,- incorporate the specific requirements of national legislation, and- design and develop a sampling plan for use on a case-by-case basis.ISO 18400-101:2017 is applicable to sampling of soil and soil material, more specifically, e.g.- soil in the landscape,- soil stockpiles,- potentially contaminated sites,- agricultural soils,- landfills, and- forest soils.Ultimately, the sampling plan provides the sampler with detailed instructions on how sampling should be carried out.NOTE 1 There might be a need for more than one sampling plan to meet all the requirements of the investigation programme.NOTE 2 It might sometimes be appropriate to divide a site or above-ground deposit (e.g. stockpile) into two or more zones and to develop separate sampling plans for each zone. For example, a (potentially) contaminated site might be zoned on the basis of past use, future use, topography or geology and an agricultural site on the basis of known or suspected soil types or use (pasture, type of crops, etc.).