Today it is scattered clouds in Ashburn

7 Day Forecast In Ashburn

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    Humidity - 63%
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    Humidity - 65%
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    Humidity - 71%
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    Humidity - 70%
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    scattered clouds - 26°
    Humidity - 62%
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    clear sky - 28°
    Humidity - 56%
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A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  


Acid Soil

A soil with a pH of less than 7.0. For practical purposes this typically relates to a soil with a pH of less than 6.5.


A soil condition where the pH is below 7.0.

Active Ingredient

The part of a pesticide from which the efficacy is obtained. The actual toxic material(s) present in a formulation.


Operations, which are carried out to improve turf by physical methods to ventilate the soil to improve drainage and to encourage better root.


Having gaseous oxygen as part of the environment.


A broad category of coarse particulate material including sand, gravel, crushed stone and recycled concrete. Due to the relatively high hydraulic conductivity value as compared to most soils, aggregates are widely used in land drainage applications.


A specialist dealing with the interactions of the soil (or rootzone) and its associated crop, e.g. turfgrass. A turfgrass agronomist advises on effective ways of constructing, developing and managing turfgrass areas.


The genus name for Bentgrasses. The main turfgrasses of this genus are A. capillaris (Browntop Bent), A. castellana ('Highland' Browntop Bent), A. canina ssp canina (Velvet Bent) and A. stolonifera (Creeping Bent), all of which are mostly used on fine turf areas.


Dark green slime (also called Squidge) which can be present on poorly drained turf areas. A soil with a pH of greater than 7.0.

Alkaline Soil

For practical purposes this typically relates to a soil with a pH greater than 7.5.


A soil condition where the pH is above 7.0 (alkaline soil).

All-Weather Surface

A term used to describe different types of artificial, non-grass surfaces. They are not actually "all weather", as a frozen, snow covered surface would not be played on, particularly from a health and safety perspective.


The mixing of a soil ameliorant (or soil amendment) to soil to give it better textural or structural properties and/or drainage.


The breakdown of complex organic molecules within dead and decaying organic matter to ammonium, which is the start of the nitrification process.

Anaerobic Conditions

With little or no oxygen e.g. compacted badly drained soils.


1. A detailed examination of the findings of an assessment.

2. A statement of the findings of an assessment, soil test, observation, or similar event.


The structure of a plant, looking at the internal features, particularly the cells and their assemblage into tissues.


A plant that completes its life cycle within one year.

Annual Meadow Grass

See Poa annua.


Colletotrichum graminicola. A fairly common disease of annual meadow grass in compacted fine turf areas.


A person, typically a novice, who is learning a trade, normally in a formal working environment, and who will become a skilled worker upon successful completion of the apprenticeship.


The scientific study of past societies through artefacts, fossils, etc.


Adams and Stewart Soil Binding test. Also known as a Mottie test. This is carried out in a laboratory situation to determine the strength of clay loams. This test is particularly useful for determining the suitability of a soil for cricket pitches and tennis courts.


1. Estimating the composition of something. For example the size and amount of different species within a turf area. By carrying out an appropriate number of assessments on an area, e.g. a cricket square, a groundskeeper / turf manager will be able to analyse the results to enable informed decisions to be made for maintaining the area to a good standard: Assessments are an important part of the Performance Quality Standards framework.

2. Providing a judgement of something. For example, (i) a portfolio presented by a student to an assessor; (ii) a health and safety risk assessment.


Acronym for American Society of Testing and Materials.

Attenuation (Water)

The retention of water within the ground (and the reduction of flood water).


A tool for boring into the soil and withdrawing a small sample for field or laboratory observations.

Available Water Capacity

Water that is held on the outer coating of soil particles and is freely available to the plant. It is the water which is retained in a soil between its field capacity and permanent wilting point.

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Basic Quality

Within the Performance Quality Standard framework, this is where a surface is designed within tight financial limitations and is for use at recreational level.


Reference or measurement standard used for comparison.


The continuous activity of identifying, understanding and adapting best practice and processes that will lead to superior performance.


Usually a term for the Bentgrasses, however, it is also applied to the flowering stem of perennial ryegrass, especially during the middle to end of summer when leaf growth has slowed due to a reduced water supply and the plant attempts to set seed.

Best Value

This is about making arrangements to secure continuous improvement in the way in which an organisations functions are exercised, having regard to a combination of economy, efficiency and effectiveness.


A plant that completes its life cycle in two years. Vegetative growth is achieved in the first year, with flowering and seeding in the second year.


The main part of a grass leaf, also called lamina.

Black Layer

This is the name given to a layer formed in the soil profile under wet and anaerobic conditions. The formation of the black colour is due to the production of iron sulphide.

Blinding Layer

A layer of grit which acts as a filter at the interface between coarse and fine aggregate (e.g. gravel and sand).


The science of plants and plant life itself.

Bowling Crease

The bowling crease is the line through the centres of the three stumps at that end. It is 8 ft 8 in / 2.64 m in length, with the stumps in the centre.

Broadcast Application

Reference or measurement standard used for comparison.

Brown Patch

Rhizoctonia solani. A turfgrass disease that may be increasing within the British Isles due to changing climate patterns.


The practice of moving a brush against the surface of a turf to lift non-vertical stolons and/or leaves before mowing to produce a uniform surface of erect leaves.

Bulk Density

Bulk density is defined as the dry mass of soil per unit volume: it is how much a certain volume of soil weighs, including the pore spaces within the soil. The standard measurement is grams per cubic centimetre, or g cm-3.

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Chemical symbol Ca. Soils usually contain adequate amounts of calcium. It can also form part of other fertiliser components, e.g. Superphosphate supplies Phosphorus, but also includes Calcium.


Measure rate of application of a spreader or sprayer under defined conditions.

Capillary Action

Movement of water between soil particles by virtue of surface tensional forces at the soil/particle interface and between the cells of any organism.


An organic, carbon, molecule with the building block (CH2O)n. There are different types of carbohydrate, e.g. sugar, cellulose etc.

Carrying Capacity

The level of recreation use an area can sustain without an unacceptable degree of deterioration of the character and quality of the resource or of the recreation experience. (Same as Sustainable Usage Level).


Soil and plant remains excreted and deposited by earthworms on the turf surface or in their burrows.

Chain Harrow

An implement comprising a series of vertical tines, loosely linked together, that is towed across the surface to improve surface aeration and surface uniformity.

Chafer Grub

Small white grubs with noticeable sets of front legs, which eat grass roots.

Chisel Tine

A thin tine, with a narrow blade which is broader at the end that penetrates the turf.


The green pigment in plants, which is vital for photosynthesis.


Particles with a diameter of less than 0.002 mm. They are plate like in shape.

Clay Soil

A soil type containing 40% or more clay-sized particles.


The process in which the soil aggregates and individual soil particles are forced into closer proximity by the application of an external force.


This combines the knowledge, skills and understanding to be able to perform a task or job effectively to defined (national) standards and over a period of time.

Compound Fertiliser

A fertiliser which includes two or more main nutrients and results from a chemical process which combines the nutrients: It is only produced commercially.

Contact Herbicide

An herbicide that kills weeds by direct contact rather than by translocation.

Cool Season Turfgrass

Species of turfgrass that, typically, have optimum growing temperatures of between 60 and 75°F. Common species include Agrostis, Festuca, Lolium and Poa, all of which are common to turfgrass areas within the British Isles.


A method of turf cultivation in which soil cores are removed by hollow tines or spoons (see Hollow Tining).

Cricket Loam

A blend of sand, silt and clay tailored for use in the construction and maintenance of cricket tables.


A plant of a single species that differs from another in specific characters such as disease resistance, time of flowering, height of flowering culm, leaf width, and habit of growth. A cultivated variety of a species.

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Remove an excessive thatch accumulation either (a) mechanically, as by vertical cutting, or (b) biologically, as by top dressing with suitable soil and aeration.

Design & Construct Contract

In this type of contract, the contractor is responsible for taking a concept developed by the employer (often set out in an ‘Employer’s Requirements’ document prepared by a consultant), completing the detailed design, and then pending the employer’s approval on the design, proceed with construction.


Surface moisture on grass leaves. This is usually caused by atmospheric moisture condensing onto leaves and/or by guttation.

Disease Tolerance

A species or cultivar showing some degree of tolerance to a disease infection.


A piece of turf that has come detached from the sward through the action of a golf club, football boot etc.

Dollar Spot

Sclerotinia homoeocarpa. A small patch disease (with 'circles' being less than 25 mm diameter) of slender creeping red fescue.


Resting stage through which a plant or ripe seeds usually pass and during which nearly all outward signs of life come to an almost complete standstill.

Drag Brush

A bristle drag (with bristles typically being 75-100 mm in length) which is about 2 m wide and is used for removing dew and worm casts and also for brushing grass upright prior to mowing.

Drag Mat

A flexible steel mat, which is pulled along to work in top dressings, more particularly on undulating turf surfaces.


The natural or artificial removal of surface and subsurface water.

Drainage Layer

An alternative term for a ‘raft’ which is a layer of gravel or stone chippings typically constructed 300 mm beneath a sports field to provide a means of collecting excess drainage water.


Transported rock debris overlying solid bedrock.


There are different types of drought, two of which are of particular interest to a turf manager:
1. Agricultural drought.
2. Meteorological drought.

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Members of the Annelida phylum. Whilst they are beneficial in improving soil aeration and the breakdown of organic matter, some species produce surface casts which have a detrimental effect on playing quality. They can also seal sand slits, thereby reducing the effectiveness of expensive drainage systems.


Abbreviation for the England and Wales Cricket Board.


The branch of biology concerned with the relationship between organisms and their environment.


Either the trimming of the perimeter of a grassed area by hand edging shears or the forming of a newly cut edge by the use of a half-moon edging iron.

Environmental Management Plan

A document providing a framework for dealing with the pollution risks associated with a site and activities on that site.


Water loss caused by the combined effects of direct evaporation from a surface and transpiration by plants.

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Fairy Rings

There are 3 types of fairy rings, each affecting turf in different ways:

Type 1: The most serious, which kills the affected turf and contaminates the soil. Mostly caused by Marasmius oreades.

Type 2: This produces green rings and occasional mushrooms and other fruiting bodies. It only really has a cosmetic effect on the turf which can be addressed by fertilising the sward or applying a turf tonic, depending upon the time of year.

Type 3: This produces fruiting bodies only and has a negligible effect on turf. All that is required is the picking of the fruiting bodies.


The application of essential plant nutrients to a grassed area.


This provides one or more essential plant nutrients to aid growth and health and can be applied to the turf surface or rootzone. The main fertiliser nutrients applied to turf are Nitrogen, Phosphorus and Potassium, followed by Iron and occasionally Magnesium.

Fertiliser, Analysis

The percentage by weight of the components found in a fertiliser. For 3% Phosphoric Acid (P2O5) and 7% potash (K2O). This information must be stated on the package.

Fertiliser Ratio

A ratio of the basic weights of the major nutrients found in a fertiliser. For example, a fertiliser ratio having an analysis of 18-6-6 would have a 3:1:1 ratio or 3 parts N to 1 part P2O5 and 1 part K2O.


The genus name for the fescue grasses. The main turfgrasses of this genus are: F. rubra ssp commutata; syn. F. nigrescens(Chewing's fescue), F. rubra subspecies (ssp) litoralis or ssp pruinosa (Slender creeping red fescue), F. rubra ssp rubra (Strong creeping red fescue) and F. longifolia (Hard fescue), all of which are mostly used on fine turf areas.


Accumulation of dead plant material in various stages of decay, and living (possibly moribund) stems and root at the turf base. It is usually tough and wiry in texture.

Field Capacity

Following drainage in a soil, which is typically 1 - 3 days after rainfall, this is the amount of water that remains in the soil profile and is the commencing point for the available water capacity. It is the maximum amount of water that a soil can retain against the force of gravity.


A term to describe the condition of soil when it is prone to crumbling rather than to deforming plastically.


Plants lacking chlorophyll that cannot produce their own food, parasitic forms cause turf diseases.


Any chemical which controls or destroys the growth of a fungus.

Fusarium Patch

Scientific name = Michrodochium nivale. The most destructive disease of fine turf areas, especially those dominated with annual meadow grass.

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A science that deals with the history of the earth as recorded in rocks.


Permeable fabric used to separate, filter, reinforce or protect soil.


The beginning of visible growth of a plant as it emerges from the seed.


Acronym for the Grounds Management Association, a not-for-profit membership organisation.


The slope of the ground usually expressed in terms of height increase (or decrease) over a given length eg. 1:200, 1:150.


The process of using cultivation to improve uniformity of surface levels.


There is something in the order of 9000 species worldwide. Only a handful are used in turfgrass situations in the UK: Bentgrass species, Fescue species, Perennial ryegrass and Smooth stalked meadow grass being the main ones.


Any loose rock that is larger than 2 mm in its smallest dimension and no more than 64 mm in its largest dimension.

Gravel Bands

Narrow gravel-filled trenches, typically 30 mm wide and 250 mm deep, installed above a network of lateral drains to improve surface drainage.


This is the light combing of the surface of a fine turf area.


A surface drain comprising of a perforated cover, set just below the surrounding land to provide a receptor for water accumulating on the surface.


Water droplets formed by exudation from the leaf, particularly under conditions of relatively high humidity.

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The consolidating of soil into an excavated area by a person using the heel of the foot.


A chemical used to destroy or inhibit plant growth.

High Quality

Within the Performance Quality Standard framework, this is where the surface is designed for professional and international use.

Hollow Tine Aeration

A form of aeration in which hollow tines (usually cylindrical) are used to remove cores of soil typically 10 mm) id diameter and up to 100 mm deep. Can be carried out with a hand hollow tine fork or using a powered aerator.


A plant which is the result of breeding between two different species or cultivars.

Hydraulic Conductivity

The rate of water flow through the soil.


A branch of geology that studies water on the earth and in the atmosphere.

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The spread of harmful weeds, diseases or insects in a turf area.


The downward entry of water into the soil.


Any chemical used to kill insects eg. Gamma, HCH.


Chemical symbol Fe. This is only included in small amounts in turf fertilisers, usually as sulphate of iron. It helps to green up the grass without producing a flush of growth, as usually occurs following an application of nitrogen.


The application of water to a grassed area. Small areas can be irrigated by using a hose pipe and attachment. Larger areas, especially high quality sports turf ones, will have fixed automatic pop-up sprinklers.


The International Organization for Standardization which is made up of national standards institutions from around the world. ISO is not an abbreviation, it is a word that is derived from the Greek ‘isos’, meaning 'equal'. The short form of the organisations name in any language is always ISO.


A line on a map connecting points below which a particular rock stratum has the same thickness.

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Knitting In

This is used to describe turf which has recently been laid and with the joins between the turves having been top-dressed to encourage a rapid production of a uniform sward surface, without visible joins being present.

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Lawn Sand

A mixture of sulphate of ammonia and sulphate of iron mixed together with lime-free sand in the ratio 3:1:20 by weight.


Rainfall and irrigation water washes out soluble elements from the soil solution. Leached elements end up in streams, rivers and aquifers.


Generic term for the sum of the grass blade, ligule and auricle (where present).

Leaf Spot

Scientific name = Drechslera spp. Also called Melting out. Minor diseases of some turf grasses; the main ones being on perennial ryegrass and smooth stalked meadow grass.


The larvae (grubs) of the crane fly or daddy longlegs (Tipula species). They cause severe damage to turf areas over the autumn to spring period when they are feeding on grass roots. The effects are particularly noticeable during dry spring weather when the turf starts to die off due to an inadequate root mass, which cannot provide adequate water and nutrients to the plant.


Small, usually whitish, growth at the junction of the leaf and sheath. Some grasses have a small fringe of hairs instead of the whitish feature.


An alkaline substance spread on turf to correct acidic conditions. The form most commonly used on turf is ground limestone (containing Calcium and sometimes Magnesium carbonate).

Liquid Fertilisation

A method of nutrient application as a solution of dissolved fertiliser.

Lolium perenne

Perrenial ryegrass.


A soil that contains 7-27% clay, 28-50% silt and more than 52% sand.


An implement consisting of an angle iron attached to a handle, used to work top dressing into hollows and hollow tine holes.


A method of surface working and levelling for soil, top dressing, compost, sand or like media, by use of a lute.

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Essential elements which are required by the grass plant in a relatively large amount. Macro-nutrients include carbon, oxygen and hydrogen, which are obtained from the air and water; nitrogen, phosphorus, potassium, calcium, magnesium and sulphur are obtained from the soil solution. Iron is sometimes included as a macro-nutrient. Silicon can also be a significant component of turfgrasses, although it is not classed as an essential element.


These are pores within the soil that are typically greater than 50-75 m (0.05 - 0.075 mm) in diameter.


Chemical symbol Mg. This is not a regular component of turf fertilisers, however, it may be required on sandy soils where it can be leached out.

Major Nutrients

Major plant nutrients are nitrogen, phosphorous, potassium, calcium, sulphur, and magnesium.


Calcareous clay.


Also called trace elements. Essential elements which are only required in relatively small amounts by the grass plant. These include iron (which is sometimes classed as a macro- nutrient), boron, chlorine, copper, manganese, molybdenum and zinc.


A low growing plant which can affect the quality of a turf area quite significantly. Different species can occur in a wide range of situations. Moss typically occurs under the following situations:

Moist or very dry turf; An acid soil with low fertility and especially a weak turf; A turf which has been mown too closely; Shade conditions; A compacted soil; Autumnal conditions which produce warm soils, humid air and short day lengths.

Mottie Test

A laboratory test of the strength of soil used for the top dressing or construction of cricket pitches.


Spots of different colours (typically red) on the surface of a broken lump of soil which is indicative of seasonal water logging.


Machines used to cut grass. Different types of mowers include cylinder and rotary which are the commonest two, whilst flail and reciprocating knife mowers are used on infrequently mown areas.


This is the removal of leaf growth from the grass plant by means of a mower.

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Neutral Soil

A soil with a pH of 7.0. For practical purposes this typically relates to a soil within a range of pH 6.5 - 7.5.


Chemical symbol N. The main nutrient applied to turf. It also has the most influence on the appearance and content of the sward and produces noticeable leaf growth.


A point on a stem (which can be a grass shoot, rhizome or stolon) from which arises a leaf, shoot or root, depending upon the type of stem.


Any food or material that nourishes or promotes plant growth.

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Organic Matter

Material within the soil which consists of decaying and decayed organic remains of plants and soil animals.


A point at which water exits a drainage system (typically into a ditch or watercourse). A ‘positive outfall’ is where the difference in levels ensures that the drainage water is always flowing.


Renewing existing white lines on a pitch using a proprietary compound.

Over-Sowing (Over-Seeding)

Application of additional seed to an existing sports field to address grass loss through wear.

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A term given to a soil layer that is appreciably more compact and less permeable than the layers above or below it.


An organism that takes its food from the living tissues of a host organism, causing some damage to the host.

Percolation Rate

The rate at which water moves through soil.


A plant that takes more than two years to complete its life cycle.

Perennial Ryegrass

See Lolium perenne.

Performance Indicator

This means the measure of a best value authority's performance in exercising a function.

Performance Quality Standard

A complete representation of a product that has a range of clearly defined and measurable criteria that are associated with a specified level of quality.

Performance Standard

A criterion, or function, of a product that has a defined parameter of measurement and is measured using a stated method of test. The defined parameter of measurement may be different for the three levels of quality within the performance quality standards.

Permanent Wilting Point

Water which is held very tightly by soil particles and is unavailable to the plant. To prevent a plant from wilting, additional water must be added to raise the water content above this point.


The readiness with which soil can be pervaded by water.


The ability of a species or cultivar to survive, especially under heavy wear conditions.


Used to describe a pesticide that remains in the environment for a long time.


Any substance or mixture of substances intended for preventing or controlling any unwanted species of plants and animals and includes any substances intended for use as a plant growth regulator, defoliant or desiccant. Would include fungicides, herbicides and nematicides. As per FEPA 1985, “any substance, preparation or organism prepared or used for destroying any pest.”


The pH scale ranges from 0 to 14, i.e. from acid to alkaline, with neutral being pH 7.0 and with the pH of soils within the UK mainly falling within the range pH 4.0 - 8.0.


Chemical symbol P. Required for seed and root development, particularly on newly establishing turf areas: Mature swards do not require as much applied phosphorus. Phosphorus is also readily held onto by soil particles and is not leached.


The process of light being captured by the chlorophyll within a plant, which is then used to make carbohydrates.

Playing Quality

Within the Performance Quality Standard framework, this represents how the facility will play when it is being used.

Poa annua

(Annual meadow grass). The commonest weed grass which is found in lawns and sportsturf.

Poa pratensis

Smooth stalked meadow grass - A hard wearing grass which is used in medium-fine and winter games areas.

Popping Crease

The popping crease is in front of, and parallel to, the bowling crease and 4 ft / 1.22 m from it. The popping crease is marked to a minimum of 6 ft / 1.83 m on either side of the imaginary line joining the centres of the two middle stumps and is considered to be unlimited in length.

Pop-Up Irrigation

An irrigation system comprising an arrangement of sprinklers that rise above the playing surface during operation and return to a position that is flush with, or just below, the surface upon completion.

Pore Space

The total space not occupied by soil particles in a volume of soil.


Chemical symbol K. This may help with improving drought resistance in plants and is also prone to leaching from sandy soils.


Acronym for Performance Quality Standard. This has three levels of quality: High Quality Standard, Standard Quality Standard and Basic Quality Standard (See Glossary for each). PQS can be defined as, 'A complete representation of a product that has a range of clearly defined and measurable criteria that are associated with a specified level of quality'.


Preconditioning of the seed prior to planting by placing it in a moist, oxygenated environment at optimum temperature to favour more rapid germination after seeding.

Primary Shoot

The simple shoot stage in the development of a grass seedling.

Presentational Quality

Within the Performance Quality Standard framework, this is the look of the facility. Users often perceive the facility to be good if it is well presented, without too much consideration being given to many of the underlying structural factors.

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The 'degree to which a set of inherent characteristics fulfils requirements' (BS EN ISO 9000). The three different levels of Performance Quality Standard set well defined requirements.

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An alternative term for a ‘drainage layer’ which is a layer of gravel or stone chippings typically constructed 300 mm beneath a sports field to provide a means of collecting excess drainage water.


This can relate to the use of a landscape rake - for the raking of soil when preparing ground, a garden type rake - for the raking of leaves or soil, a springbok rake - for leaves or a very light scarification, or a 'scrake' - a special scarifying rake.

Rate of Seeding

The seed rate used eg. grams per square metre or kilograms per hectare.

Red Thread

Scientific name = Laetisaria fuciformis. A common, mainly cosmetic, disease of red fescues and perennial ryegrass, which are growing in low nitrogen conditions.

Release Rate, Fertiliser

That rate of nutrient release following fertiliser application. Water soluble fertilisers are termed quick release, while insoluble or coated soluble fertilisers are referred to as slow release.


To rebuild a turf using an existing turf as the seedbed ie. Surface cultivation and reseeding a badly worn soccer goalmouth.


The inclusion of synthetic fibres within the rootzone to increase wear resistance and strength.

Return Crease

The return creases are at right angles to the popping crease at a distance of 4 ft 4 in / 1.32 m either side of the imaginary line joining the centres of the two middle stumps. Each return crease is marked from the popping crease to a minimum of 8 ft / 2.44 m behind it and shall be considered to be unlimited in length.


An underground stem which gives rise to roots and shoots at the nodes. A rhizome is often scaly, i.e. with very small types of leaves. Example plant = Couch grass, Elymus repens, syn. Agropyron repens.


A pattern of low 'ridges' or ribs appear during mowing. This can occur where a cylinder mower has been set incorrectly, with either the cutting height being too short for the grass or where the bottom blade is too tight against the cylinder.


This can be used to firm, that is consolidate, but not to compact the turf surface and is especially useful in firming the soil after any surface heave has occurred during the winter or spring.

Root System

The underground downward growth of a plant; anchors plant to the soil and absorbs moisture and nutrients from the soil for use by the entire plant.


The layer of growing medium in which the majority of plant roots are found. (When applied to ameliorated soils or soil mixes the rootzone is defined by the layer thickness at construction rather than by the amount of roots present at any depth).


The movement of excess water across the surface of a playing field following significant rainfall.

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Safety Margin

An additional area around the perimeter of a court or pitch to reduce the risk of injury to players as a result of interaction with adjacent games or site infrastructure.


Particles with a diameter from 2 mm to 0.05 mm. For turfculture purposes, sand is divided into several groups: Very coarse (2 – 1 mm); Coarse (1 - 0.5 mm); Medium (0.5 - 0.25 mm); Fine (0.25 - 0.125 mm) and Very fine (0.125 - 0.05 mm).

Sand Amelioration

The application and incorporation of sand into the surface of a sports field to improve playability.

Sand Grooves

Narrow slits, approximately 150 mm deep and 20 mm wide, introduced by a machine at a spacing of 260 mm to improve surface drainage. These grooves are forced into the soil with a tine rather than being created by excavating a narrow trench, and can be filled with sand or fine grit.

Sand Slit

Grooves, of various sizes, within a turfgrass area. A typical size of sand slit is 250-300 mm depth x 25-50 mm width and at 1 m spacing. These are cut throughout the whole of an area, such as a football pitch, to improve drainage and playing quality.


To cut the turf from the soil, or to mow extremely close, or to cut into the grass crowns.


A cultural operation carried out by means of a rake, or a mechanically operated implement to produce a healthy vertical type of growth of the desirable grasses. The process brings up flat growth of the grass so it may be mown off, so giving the turf a ‘clean look’.


browning of turf caused by misapplication of fertiliser or pesticide, spill of hydraulic oil, etc.

Secondary Drainage

Drainage systems designed to intercept surface water and convey it to a subsurface drainage system (e.g. sand grooves, slit drains and gravel bands).

Seed Mixture

A mixture in various proportions, of seed of different species or cultivars. The inclusion and the proportions of species and cultivars in the mixture depend on the use to which the turf will be put in the future.


A term referring to the state of soil following preparation for seeding (i.e. through cultivation). Typically, the tilth would be characterised by fine crumb structure.

Selective Herbicide

A weed killer capable of controlling one type of weed without damaging other types of more desirable plants.


A general term referring to any sharp object encountered in the workplace, particularly items such as broken glass or nails in wood. The term also refers to hypodermic needles.

Shear Strength

The resistance of the surface layer to horizontal motion through it. This property governs the degree of traction or grip obtained by a player wearing studded or spiked footwear.

Shoot Density

The number of grass shoots per unit area.


Particles between sand and clay, with a diameter of between 0.05-0.002 mm.

Site Waste Management Plan

A document that sets out how resources will be managed and waste controlled at all stages during a construction project. In England, a site waste management plan (SWMP) is required for all construction projects worth more than £300,000.

Slit Drains

A series of narrow, commonly 50 mm wide, sand and gravel filled trenches excavated across, and into the porous backfill of, lateral drains below. Slit drains are typically 250 to 350 mm deep and installed at 0.5 to 2.0 m spacing.

Slit Tine

A thin tine, with either a diamond shape or a narrow rectangular shape with a curved end.


A method of turf cultivation in which vertically rotating, flat blades slice intermittently through the turf and the soil. Also called slicing or slit tining.

Slow-Release Fertiliser

Designates fertiliser with a rate of dissolution less than that of completely water-soluble fertilisers; may involve compounds, which dissolve slowly, materials that must be decomposed by microbial activity, or soluble compounds coated with substances highly impermeable to water. ‘Slow release’ used interchangeably with ‘delayed release’, ‘controlled release’, ‘controlled availability’, ‘slow acting’ and ‘method release’, eg. IBDU.

Smooth Stalked Meadow Grass

See Poa pratensis.


An underground structure that disposes of unwanted water, most commonly storm water runoff, by dissipating it into the ground, where it merges with the local groundwater.

Soil Aeration

The exchange of atmospheric air and soil air.

Soil Air

This is the composition of the air within the soil and the concentration of the main gases are very similar to that which are found in the atmosphere.

Soil Acidity

The degree of acidity or alkalinity of a soil. The soil reaction (the degree of acidity or alkalinity in terms of hydrogen ion concentration) is presented on the pH scale ranging from 0, very highly acid to 14, very highly alkaline. Most soils in Britain range from pH 4.0 to pH 8.0.

Soil Compaction

A reduction of air-filled pore space in soil following loading, resulting in an increase in dry bulk density.

Soil Fertility

This refers not only to the plant food status or the soil but also aeration, moisture supply, organic matter content and acidity of the soil.

Soil Organic Matter

the organic fraction of the soil, which includes plant and animal residues at various stages of decomposition, tissues of toil organisms and other products formed by the soil population.

Soil Organisms

These range greatly in size and include moles, earthworms, protozoa, fungi and bacteria. Living organisms are very important in the breakdown of organic matter in the soil.

Soil Porosity

This is the amount of pore spaces within a soil and is primarily influenced by the structure of the soil. Soil porosity is usually divided into Air-Filled Porosity and Water-Filled Porosity.

Soil Profile

A vertical section of the soil through all its horizons. Such a profile will show the depth of tap and subsoil, degree of compaction etc. A cross-section through an area of land.

Soil Structure

The manner in which primary soil particles (ie. sand, silt and clay) are grouped into aggregates. The binding together of particles is brought about by complex interactions between soil particles, organic matter and various chemicals in the soil.

Soil Tests

Laboratory tests to determine eg. the pH (acidity or alkalinity) and nutrient status of a soil.

Soil Texture

Soils are classified into their various textural classes such as sandy loams, loams or clays by their percentage of clay, silt and sand. The texture of the soil maybe determined in a laboratory test or by smearing the soil in the hand and adjudging its stickiness or grittiness.

Solid Tine

A narrow spike, similar to that of a garden fork, but usually chunkier.


Abbreviated to spp. (singular = sp.). A group of individuals which interbreed with each other, but generally not with other species.


An explicit set of requirements to be satisfied by a material, product, or service.


A method of turf cultivation in which solid times or flat pointed blades penetrate the turf and soil surface.

Springbok Rake

A hand tool for thatch and moss removal and leaf raking.


See Algae.


A (technical) document that contains precise criteria that can be used as guidelines to ensure that materials, products, processes and services are fit for their purpose.

Standard Quality

Within the Performance Quality Standard framework, this is where the surface is designed for general club use.


A stem which grows above ground in a horizontal manner. It gives rise to roots and shoots at the nodes. Example plant = Creeping bent - Agrostis stolonifera.


a condition under which a plant suffers due to lack of moisture, nutrients, extreme heat or any combination of the three.


Acronym for the Sports Turf Research Institute.

Structural Quality

Within the Performance Quality Standard framework, this can be considered the physical make up of a particular facility, which includes vegetation, soil and organisms.


Where excessive compaction exists in a soil this can be relieved without causing severe surface disruption by sub-aeration using a mini mole plough or either the rigid or vibrating type.


The layer of soil under the topsoil.


A tractor-drawn implement for alleviating compaction in the subsoil.

Sulphate of Iron

Used as a turf tonic to help produce a darker green colour to the sward and assists in 'hardening' the grass against disease attack.

Summer of Dormancy

The cessation of growth and subsequent death of leaves of perennial plants due to heat and/or moisture stress.

Surface Heave

The production of an uneven playing surface by soil being forced upwards or during drainage work, sub-soiling or sub-aeration etc.


A material that improves the emulsifying, spreading, wetting and other surface modifying properties of chemical formulations.


Not normally applied specifically as a fertiliser, as it is included in several other fertilisers which are commonly applied, e.g. ammonium sulphate. Powdered elemental sulphur is sometimes applied to turf and soil to reduce the soil pH, however, great care needs to be taken during application to ensure an even spread is given and also any thatch which is present is not of too high a density otherwise the sulphur can become lodged within the thatch, producing excessive localised acidity which would be detrimental to the sward quality.

Sustainable Usage Level

This is considered to be that which gives the maximum usage of a pitch, or facility, without causing an unacceptable reduction in playing quality. (Same as Carrying Capacity)

Sustainable Urban Drainage Systems (SUDS)

Water management practices and facilities designed to drain surface water in a manner that will provide a more sustainable approach than what has been the conventional practice of routing run-off through a pipe to a water course.


The total surface content of a grassed area, including grasses, bare areas, weeds, pests and disease content. Often synonymously referred to as turf or turf sward.


Sometimes called swishing. Using a bamboo or fibreglass switch to remove dew and exudates from turf by moving the switch in an arc while in contact with the turf surface. Also used to break up earthworm casts and clumps of clippings.

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Take-All Patch

Scientific name = Gaumannomyces graminis. A destructive disease of bentgrasses which attacks the roots of the plant, unlike the majority of the other turfgrass diseases which attack the leaves.


A layer of intermingled dead and living shoots, stems and roots that develops between the zone of green vegetation and the soil surface.

Thatch Control

Prevention of excessive thatch accumulation by cultural manipulation and/or reduction of excess thatch by mechanical or biological means.

Thatch Fungi

A group of Basidomycete fungi, which feed upon excessive thatch in fine turf, producing localised patches or rings, which destroy that playing surface. Sometimes called superficial fairy rings.


The state of the upper layers of the soil, in respect of size of aggregations, resulting from cultivation and/or weathering.


A spike or prong such as that on a garden fork.


Degree to which a plant endures a stress.


Bulky material added to turf to improve the surface layers. It is usually physically worked in by matting, raking or brushing and often contains sand, compost and organic matter.


The practice of graphic delineation in detail, usually on maps or charts, of natural and man-made features.


The soil horizon immediately below the grass sward (typically extending to between 100 and 300 mm below the surface).

Total Porosity

The total amount of pores within the soil.

Total Weed Killer

Herbicide used to kill all existing vegetation and to keep a clean weed-free surface, eg. on footpaths, car parks or hard tennis courts.


Abbreviation for Total Quality Management. Customer satisfaction and continuous improvements are its main focus. TQM "assures maximum effectiveness and efficiency within an organization by putting in place processes and systems which will ensure that every aspect of its activity is aligned to satisfy customer needs and all other objectives without waste of effort and using the full potential of every person in the organization".

Trace Elements

see Micro-nutrients.

Traditional Contract

In such a contract the employer contracts with an architect, engineer or consultant to carry out the design. The architect, engineer or consultant, acting as the agent of the employer, supervises the construction of that design. The contractor enters into a contract with the employer to build that design.


The transfer of water vapour from the plant to the atmosphere.


An area of grass which includes the leaves and roots as well as the rootzone, or at least part of it. It may refer to an existing turf area, such as an amenity lawn, or turf which is to be laid.


A term referring to the state of soil following preparation for turfing (i.e. through cultivation). Typically, the tilth would be characterised by fine crumb structure.


The study of turf maintenance and the management of the turf environment.

Turf Cutter

A machine used to cut turf (sods) for future transportation and relaying.

Turfgrass Culture

The composite cultural practices involved in growing turfgrasses for purposes such as lawns, greens, sports facilities and roadsides ie. Non-agricultural use.

Twin Wall Pipe

Drainage pipe that is corrugated on the outside to provide additional strength, but smooth on the inside to reduce frictional losses during the conveyance of water.

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An organic compound that is now produced artificially and may be used as a fertiliser (46% N). Also called carbamide (NH2)2CO.


A slow release fertiliser providing gradual release of nitrogen over a period of time.

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Value for Money

The best use of available resources within a budget to provide a suitable relationship between capital and recurrent costs; to satisfy the user and to afford the opportunity for efficient management. Sometimes abbreviated to VFM.

Vertical Cutting (mowing)

Involves a mechanical device having vertically rotating blades that cut into the face of a turf for the purpose of controlling thatch or grain. Verti-drain a tractor drawn machine, which can break up compaction by means of tines and provide cracks and fissures along which water movement and root growth can take place.


This is a very light form of scarification carried out on fine sports turf areas, which raises loose vegetation at the base of the grass plant.


A tractor mounted implement for aeration. It typically has 12-18 solid or hollow tines of 18- 25 mm diameter, being 300-400 mm in length. These are punched into the ground and on their extraction can cause shattering of the soil profile to aid drainage and root growth.

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Waste Acceptance Criteria (WAC)

Criteria to be met before waste is accepted at a landfill site. There are different acceptance criteria for:
• Inert waste.
• Non-hazardous waste.


Any flowing body of water including rivers, streams and brooks.

Water-Filled Porosity

The amount of pore spaces within a soil that are filled with water.

Water Table

The upper surface of ground water or that level in the ground where water is at atmospheric pressure.

Water Table (Perched or Suspended)

The water table of a saturated layer of soil or sand, which is separated from an underlying, saturated layer by an unsaturated layer. In sports turf construction, gravel carpets are sometimes used to create a suspended water table, which increases moisture retention in the rootzone.

Wear Resistance

The resistance of the turf to wear. Good drainage, correct fertiliser use and the choice of a wear resistant species or cultivar of turfgrass can achieve this.


These are undesirable elements in a turf area. Weeds are generally divided into two groups: (a) Large- (sometimes called Broad-) leaved weeds, such as Dandelions, Daisy, Plantains etc. and (b) Small- (sometimes called Fine-) leaved weeds, such as Clover, Pearlwort, Yarrow. This division is particularly useful when carrying out quality assessments of turf areas, as it saves time identifying each individual weed specie and allows for a good indication of the type of maintenance which may be required to control the weeds.

Wet Wilt

Wilting of turf in the presence of free soil water when evapotranspiration exceeds water uptake by the roots. The inability of a plant to absorb enough moisture through the roots to equal the rapid loss of moisture through the leaves.

Wetting Agent

A chemical that improves the wetting properties of a solution. (see also surfactant).

Winter Fertilisation

a late autumn to winter application of fertiliser to turfgrasses at rates that maintain green colour without causing adverse physiological effects; used in regions characterised by moderate winters for the species involved.

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Yorkshire Fog

see Holcus lanatus.

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