Turfgrass Management Terms A

Abaxial - abaxial surface of a leaf or grass blade is the lower surface, which faces away from the plant’s axis or stem. This side of the leaf is responsible for the exchange of gases, such as the absorption of carbon dioxide from the environment and the release of oxygen from photosynthesis. Because the abaxial surface reflects light differently than the upper or “adaxial” surface, mowing swaths of grass in opposing directions creates lawn stripes

Acidic – the state when a substance, such as soil, measures between 0.0 and 7.0 on the pH scale, where 0.0 is the most acidic. When soil is too acidic, many plants can't thrive. Soil amendments, such as lime, make soil less acidic

Acid soil - soil having an acid reaction of pH below the neutral point, which is pH 7.0; a soil having an excess of hydrogen ions. Turfgrasses generally prefer slightly acid soils, in the pH range of 6.0 to 6.5. Also known as “sour soil" 

Acuminate - gradually tapering to a sharp point

Acute - sharp pointed but less tapering than accuminate, angle less than 90 deg

Adaxial - adaxial surface of a leaf or grass blade is the upper surface, which faces toward the axis or stem of the plant. This chlorophyll-rich upper leaf surface is responsible for capturing light needed for photosynthesis. Because the adaxial surface and the lower or “abaxial” leaf surface reflect light differently, mowing a lawn in opposing directions will create stripes in a lawn

Aeration - process of coring lawns to allow more air into the soil and to relieve compacted soil and encourages healthy grass growth; used synonymously with aerification. It is essentially putting holes in the turf, aeration creates pathways that allow vital air, water, and nutrients to penetrate thatch and compaction to reach grass roots. How often aeration occurs depends on the health of the turf and how heavily it is used, but most turfgrasses benefit from annual aeration

Agrostology - branch of botany concerned with the study of grasses, especially their classification. From the Greek word “agrostis,” meaning “type of grass”

Algae - growth of minute single-celled plants containing chlorophyll that develops on thin or bare areas in hot humid weather when soils are saturated with moisture

Alkaline – the state when a substance, such as soil, measures between 7.0 and 14.0 on the pH scale, where 14.0 is the most alkaline. Many plants suffer nutrient deficiencies in high-alkaline soil. Amendments, such as sulfur, reduce soil alkalinity. See also: acidic, amendment, soil pH

Alkaline soil - soil with a pH of greater than 7. Its opposite is acidic soil, which has a pH of less than 7. Soil pH ranges from 0 to 14, and most plants like soil somewhere near the neutral mark of 7. Alkaline soil is good for some plants and bad for others. Most grass varieties prefer slightly acidic soil. Also known as “sweet soil” and usually found in areas with relatively low rainfall

Amendment – substance (soil amendments) added on or incorporated into soil to improve its quality, increase its productivity, or correct deficiencies. Amendments can restore pH balance, increase nutrient availability, improve soil structure, add nutrients and deliver other benefits. Amendments such as lime affect pH and nutrient availability. Other amendments, such as organic matter, improve soil structure and deliver nutrients

Annual – plant that naturally completes its life cycle within one year. Annuals germinate from seed, flowers, produces seed, and then dies — from root to tip — each year (one growing season), regardless of climate. Some annuals self-seed and new plants grow from the seeds the next year

Anaerobic - lacking in oxygen. A soil structure that is anaerobic, typically due to poor drainage or soil compaction, will cause grasses and other plants to suffocate and eventually die. Aeration can help relieve soil compaction and improve air and water movement through anaerobic soil

Annual grasses - grasses naturally complete their life cycle in one year and then die, regardless of the growing zone. Annual grasses such as fast-rooting annual ryegrass are often used to stabilize and provide fast color to newly seeded lawns while slower-germinating perennial grasses take root

Apron - fairway area close to and in front of the putting green, adjoining the putting green collar. This area is normally mowed at fairway height but sometimes is mowed slightly closer

Attenuate- gradually narrowing to a slender apex or base

Auricle - ear-like lobes at the base of a blade or the top of the sheath

Awn - a more or less stiff bristle on the end of lemmas or glumes


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