Good practice guide for landscaping - tools

A decision tree, checklist and glossary have been developed to signpost to the relevant technical documents, assist with the application of BSI PAS 100 compost and ‘jargon bust’ some key terms related to the use of compost



Aggregation: refers to the way in which sand, silt and clay particles come together to form a soil structure

Ameliorant: substance added to soil to improve growing conditions for plants

Attrition: as part of soil remediation technology removes fine particles and contaminant from the surface of primary material i.e. soil

Biomass: refers to the mass of biological organisms in an area or ecosystem at any given time

Bioremediation: is a process which uses micro-organisms or enzymes to breakdown or remove contaminants

Biowaste: source-segregated biodegradable waste

Brownfield: refers to both known contaminated sites and any land or premises which have previously been used or developed and not currently fully in use (this excludes agricultural land) 

Bulk density: the mass of a unit volume of soil, generally expressed in g/cm3. Light and porous soils have low bulk densities, whereas heavy and compacted soils have high bulk densities

Carbon sequestration: long-term storage of carbon dioxide or other forms of carbon to mitigate global warming

Cation exchange capacity (CEC): the total amount of exchangeable cations that a particular soil, or soil forming material can adsorb at a given pH. Light textured soils (in the sandy categories) possess low cation exchange capacities (CEC) and adding compost raises the CEC of these soils. This enables the soil to better hold onto nutrients, such as potash and nitrogen, which would otherwise leach beyond the rooting depth.

Compost: solid particulate material that is the result of composting, that has been sanitised and stabilised and that confers beneficial effects when added to soil, used as a component of a growing medium, or is used in another way in conjunction with plants. This definition refers to BSI PAS 100 compost for the purposes of this document

Composting: process of controlled biological decomposition of biodegradable materials under managed conditions that are predominantly aerobic and that allow the development of thermophilic temperatures as a result of biologically produced heat

Domestic use: compost use by members of the public in their own gardens, communal or shared gardens, and allotments 

Electrical conductivity: measurement relating to the concentration of soluble ionic constituents, particularly ammonium, calcium, chloride, magnesium, nitrate, phosphate, potassium, sodium and sulfate

Food derived compost: compost that has been made from suitable low-risk food wastes such as household and commercial kitchen wastes. Facilities producing such composts are authorised by Animal Health to ensure that they achieve appropriate conditions to ensure their safety

Fertiliser: soil amendment containing nutrients (macronutrients and micronutrients), added to promote plant growth

Green compost: the feedstock used to produce green compost is source segregated material collected independently from other waste streams from sources such as domestic gardens, municipal parks and recreational areas 

Green waste: arboreal and other botanical residues such as grass clippings and other plant residues derived from parks, gardens, nurseries and amenity areas and sometimes waste from vegetable or fruit processing activities

Growing medium: material, other than soils in situ, in which plants are grown

Land reclamation: the recovery of land from a brownfield or underutilised state to make it suitable for reuse achieved through stabilisation, contouring, maintenance, conditioning, reconstruction and vegetation establishment

Land remediation: The process of making a site fit-for-purpose through the removal or containment of contaminants. Environmental damage is reversed or treated through the management, removal, sealing or treatment of dangerous substances or stabilisation in order to render the site safe for a specific use, but not necessarily for all possible uses

Land restoration: the process of making a site fit-for-purpose through (among other activities carried out), amelioration of the site’s soil or soil forming materials.

Micro-organisms: include bacteria, algae, fungi and protozoa. They recycle nutrients and actively decompose organic matter

Mulch: substance spread and allowed to remain on the soil surface to conserve soil moisture, suppress weeds and shield soil particles from the erosive forces of raindrops, run-off and wind

Oxygen diffusion capacity: the capacity of the soil to transfer oxygen to plant roots

PAS: Publicly Available Specification

Rotavator: a machine designed to break up soil using rotating blades 

Sewage sludge cake: dewatered, organic-rich sewage sludge that is an output from the sewage treatment process

Soil improver: material added to soil in situ primarily to maintain or improve its physical properties, and which may improve its chemical and/or biological properties or activity

Stable, stabilised: degree of processing and biodegradation at which the rate of biological activity under conditions favourable for aerobic biodegradation has slowed and microbial respiration will not significantly resurge  under altered conditions, such as manipulation of moisture and oxygen levels, or temperature or the addition of a source of water soluble nitrogen

Subsoil/substrata: the layer of soil below the layer of topsoil

Sustainable Urban Drainage Systems (SUDS): Surface water drainage systems developed in line with the ideals of sustainable development are collectively referred to as Sustainable Urban Drainage Systems (SUDS)

Topsoil manufacture: blending of soils available on site and potentially other organic or inorganic materials with BSI PAS100 compost to produce a soil that suits the requirements of a specific site and which provides the same function as topsoil

Tilth: state of aggregation of soil and its condition for supporting plant growth

Topsoil: the uppermost layer of soil, where the majority of biological soil activity, concerning micro-organisms and organic matter, occurs

Water holding capacity: the ability of soil to retain water and thus making it available for a longer period of time in dry conditions


Wetlands: an area where the soil is saturated with moisture either permanently or seasonally