This page is designed to provide the reader with definitions of terms with regard to turfgrass and turfgrass maintenance.
acid soil – A soil with a pH below the neutral point of 7.0. Soil acidity is determined by the concentration of hydrogen ions in solution. Turfgrasses generally prefer slightly acidic soils.
aerate – Process of aerifying soils with hollow tines, solid tines, water, or air injection: used synonymously with aerify.
alkaline soil - A soil having a basic reaction or a pH above the neutral point (pH 7.0); a soil having an excess of hydroxyl (OH) ions, usually found in areas of relatively low rainfall.
bench setting - The height at which the bedknife is set above a firm, level surface. This is generally the accepted measure for determining cutting height.
biological control - Control of turfgrass pests by the use of living organisms.
cation – Positively charged ions including potassium, calcium, magnesium, and hydrogen.
cation exchange capacity (CEC) - The sum total of exchangeable cations that a soil can absorb. The value represents the nutrient-holding capacity of the soil.
chlorosis - The condition in plants relating to the loss or lack of green color. May be caused by disease activity, albinism, or nutritional deficiency.
cool season grasses - Grasses that grow more actively during cool portions of the growing season, primarily spring and fall (e.g. bentgrass, Kentucky bluegrass, Poa annua, and perennial ryegrass).
cultivation - Turfgrass cultivation is a mechanical procedure such as spiking, grooving, high pressure water injection, and deep tine, deep drill, solid tine, or hollow tine coring on established turf without destroying its sod characteristics.
cutting height - The distance above the soil line that grasses are clipped.
fertigation - The application of fertilizer through an irrigation system.
foliar fertilizers – Soluble plant nutrient materials applied to the leaf surface and capable of being absorbed through leaves.
fungicide – A chemical that kills or inhibits fungi.
fungus – A low form of plant life which, lacking chlorophyll and being incapable of manufacturing its own food, lives off dead or living plant or animal matter.
germination – Initial growth in which a seed or spore sprouts. The growth in a seed, plant bud, or joint.
grain – As applied to putting greens, the tendency for grass leaves and runners to make horizontal growth in one direction, which interferes with the true natural roll of the ball. With today’s low mowing heights and improved maintenance practices, the effect of grain is rarely observed on highly maintained putting greens.
grooming – In putting green maintenance, the practice of lifting leaf and stem growth of grasses prior to mowing with a specialized grooming attachment affixed ahead of the cutting reel.
infiltration rate – The speed at which water moves into a soil or root zone mixture. Frequently confused with Saturated Hydraulic Conductivity (SHC) – a laboratory procedure used to measure the speed at which water moves through the pores of the soil.
ions - Many water-soluble materials which, when dissolved in water, split apart into electrically charged atoms or groups of atoms called ions. The ions with a negative charge are called anions and those with a positive charge are cations.
liquid fertilizer - Plant nutrients applied in solution.
localized dry spot - A dry area of sod and soil which repels water. Caused by various factors such as excessive thatch or fungal organisms.
macronutrient – Essential elements required in larger amounts for plant growth (e.g. nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, carbon, hydrogen, and oxygen).
microclimate – The climate of a small, distinct area such as a golf hole, green site, etc.
microenvironment - The area in the immediate vicinity of the turfgrass plant from the surface to the depth of root penetration into the soil.
micronutrient – Essential elements required in small amounts for turfgrass growth (e.g. iron, manganese, zinc, copper, molybdenum, boron, and chlorine).
microorganisms - Small organisms, such as bacteria and other minute entities, invisible to the unaided eye.
mycelium – The vegetative body of a fungus.
nematode – Small, round worms, usually microscopic and colorless, that live in moist soil, water, or in decaying or living organic matter. Plant parasitic forms puncture plant tissues by means of a stylet and live by sucking the juice of the plant.
nitrification - Biological conversion of ammonium into nitrates in soils by soil organisms.
organic fertilizer – Fertilizers containing carbon and hydrogen.
organic, natural – Fertilizers derived from naturally-occurring, complex organic compounds not readily soluble in water.
organic, synthetic - Man-made organic fertilizers such as urea, IBDU, urea formaldehyde. All slow release nitrogen except urea.
organic matter - Material derived from plant or animal source. Often added to topdressing soil mixtures to give added water and nutrient holding capacity to the soil.
overseed - To sow seed over an area that is sparsely covered with some kind of vegetation or to plant a winter turf of a cool season species within a dormant warm season turf.
pathogen – An organism that causes disease.
pesticide - An agent used to control pests such as weeds, insects, or diseases.
pH – A numerical measurement of the hydrogen ion concentration. The measurement indications of the relative acidity or alkalinity. Values below 7 are increasingly acid; values above 7 are increasingly alkaline.
phytotoxic - Harmful to plants.
post-emergence - Term used in reference to treatments, e.g., herbicide treatment made after weed seedlings have emerged from the soil.
pre-emergence -Term used in reference to treatments, e.g., treatment made before weed seedlings emerge from the soil.
resiliency -the capability of the turf to spring back when balls, shoes, or other objects strike the surface, thus providing a cushioning effect.
rhizome - An underground, root-like stem; underground creeping stem; a root stock.
salt index – Used to measure the effect of fertilizers on soil solution, and is expressed as a ratio of increase in osmotic pressure produced by a material to that produced by the same weight of sodium nitrate.
scalping – The term for removing an excessive amount of the green leaf surface, leaving a stubbly brown turf. Continued scalping will weaken or kill the turf.
soil modification - Alteration of soil characteristics by adding soil amendments such as sand, peat, etc.; commonly used to improve physical condition.
stolons – Creeping, trailing, or reclining stems or runners above ground which may produce roots and new stems and become independent plants.
thatch - A tightly intermingled layer of dead and living parts (roots, stolons, shoots, stems, etc.) that develops between the green vegetation and soil surface. One-half inch or less is deemed desirable on turfgrass surfaces.
translocation - The movement of dissolved materials from one part of a plant to another.
transpiration – Giving-off of water vapor by the plant. Evaporation of water through the stomata.
vertical mowing (verticutting) - The thinning of turfgrasses by blades or wire tines which cut perpendicular to the soil surface. Specifically designed to remove mat, thatch, and grain from putting greens; to thin dense turf.
wet wilt – When a plant wilts from lack of water even though standing in water. Roots do not function properly. Water and oxygen movement become impaired with excessive amounts of water in the soil profile.
wilt- Loss of leaf turgidity. Drooping of plant leaves due to inadequate water supply or excessive transpiration. Also a vascular disease which interferes with utilization of water by a plant or to a toxin produced by an organism.
