MOWINGMOWING

MowingMowing

most basic of all turfgrass cultural practices. most basic of all turfgrass cultural practices. A periodic removal of a portion of the A periodic removal of a portion of the turfgrass shoot. Is detrimental to the turfgrass shoot. Is detrimental to the turfgrass plant. First turf mowers were turfgrass plant. First turf mowers were animals.animals.

AdvantagesAdvantages

Controls top growthControls top growth Provides a uniform surfaceProvides a uniform surface Controls weedsControls weeds Reduces fire hazardReduces fire hazard Shoot growth is greater under mowed than Shoot growth is greater under mowed than

unmowed turfs.unmowed turfs.

DisadvantagesDisadvantages

Dec. food productionDec. food production Dec. root growthDec. root growth Dec. carbohydrate reservesDec. carbohydrate reserves Creates entry ports for pathogensCreates entry ports for pathogens Inc. water lossInc. water loss COST!COST!

Costs of Mowing in NCCosts of Mowing in NC

Airport - 83% Airport - 83% Parks - 60%Parks - 60% Athletic fields - 75% Athletic fields - 75% Roadsides - 72%Roadsides - 72% Golf courses - 43%Golf courses - 43% Schools - 66% Schools - 66% Home lawns - 75%Home lawns - 75%

Types of mowers Types of mowers

Rotary ReelFlail

- two types of cut: shearing (scissors) vs. impact

Reel MowersReel Mowers

Reel - Rotating reel with blades and a Reel - Rotating reel with blades and a stationary bedknife. Quality of cut depends stationary bedknife. Quality of cut depends on 1) blade sharpness, 2) proper adjustment on 1) blade sharpness, 2) proper adjustment of blades to the bedknife across the entire of blades to the bedknife across the entire width of the bedknife. Also affected by the width of the bedknife. Also affected by the relationship of the mowing height (MH) to relationship of the mowing height (MH) to the clip of the reel (CR).the clip of the reel (CR).

Triplex Greens Mower

Walk BehindGreens Mower

Low Budget Reel Mower

Clip of the ReelClip of the Reel CR - forward distance traveled between successive CR - forward distance traveled between successive

clips. Ideal cut occurs when the MH=CR. clips. Ideal cut occurs when the MH=CR. Controlled by three factors: Controlled by three factors:

1) forward speed of mower.1) forward speed of mower. 2) # blades on reel.2) # blades on reel. 3) rotational velocity of reel.3) rotational velocity of reel. Mowing quality decreases when speed is too high, or Mowing quality decreases when speed is too high, or

the height of turf is too high.the height of turf is too high. Marcelling - rippling effect. Marcelling - rippling effect.

Rotary MowersRotary Mowers

Rotary - horizontal rotation. Usually > 1" Rotary - horizontal rotation. Usually > 1" cutting height. Impact cut. Blade must be cutting height. Impact cut. Blade must be very sharp and well balanced. Need fairly very sharp and well balanced. Need fairly high rotational velocity to give best cut.high rotational velocity to give best cut. Objects - damage blade, engine shaft.Objects - damage blade, engine shaft. Injury - very dangerous.Injury - very dangerous. Versatile units - simple maintenance, less Versatile units - simple maintenance, less

costly.costly.

Riding Rotary Mower

Walk-behindRotary Mower

Flail MowerFlail Mower

Flail - Numerous knives, vertically mounted Flail - Numerous knives, vertically mounted which are free swinging. An impact cut. which are free swinging. An impact cut. Also recuts a lot of the leaf tissue.Also recuts a lot of the leaf tissue. Objects - less likely to throw objects. Utility Objects - less likely to throw objects. Utility

use, low maintenance areas. Lower quality cut.use, low maintenance areas. Lower quality cut.

Large Flail Mower

Mowing Height and MowersMowing Height and Mowers Mowing height with a reel mower is equal to 1/2 the Mowing height with a reel mower is equal to 1/2 the

diameter of the reel.diameter of the reel. Highest mowing quality is with reel mowers. However, Highest mowing quality is with reel mowers. However,

there are problems:there are problems: Objects - can cause a biting or dipping action to occur which Objects - can cause a biting or dipping action to occur which

disrupts the uniformity of cut.disrupts the uniformity of cut. Turns - tendency to cause the outside edge of the cutting unit Turns - tendency to cause the outside edge of the cutting unit

to dip and scalp the turf.to dip and scalp the turf. Use of reel mowers is a necessity for closely mowed Use of reel mowers is a necessity for closely mowed

turfs. Limitation on use where seed stalks are a problem.turfs. Limitation on use where seed stalks are a problem.

Decreasing the Mowing Height:Decreasing the Mowing Height:

1) Dec. carbohydrate synthesis and storage1) Dec. carbohydrate synthesis and storage

2) Inc. shoot growth/unit area2) Inc. shoot growth/unit area

3) Inc. shoot density3) Inc. shoot density

4) Dec. leaf width4) Dec. leaf width

5) Inc. succulence of shoot tissue5) Inc. succulence of shoot tissue

6) Inc. chhorophyll/unit area6) Inc. chhorophyll/unit area

Decreasing the Mowing Height:Decreasing the Mowing Height:

7) Dec. root growth rate and mass7) Dec. root growth rate and mass

8) Dec. rhizome growth8) Dec. rhizome growth

9) Dec. environ. stress tolerance 9) Dec. environ. stress tolerance (heat,drought, wear)(heat,drought, wear)

10) Dec. temperature insulation10) Dec. temperature insulation

11) Need to inc. turf manager's expertise11) Need to inc. turf manager's expertise

Mowing HeightsMowing Heights very close .125 - .5 " bentgrass, bermudavery close .125 - .5 " bentgrass, bermuda close close .5 - 1.0 " colonial bent, bermuda, .5 - 1.0 " colonial bent, bermuda,

zoysia zoysia medium 1 - 2 " red fescue, cent., KBG, medium 1 - 2 " red fescue, cent., KBG,

Per. rye Per. rye high 1.5 - 3 " bahia, tall fescue, high 1.5 - 3 " bahia, tall fescue,

St. Aug. St. Aug. Excessively short mowing increases weed invasion. Excessively short mowing increases weed invasion.

High mowing can increase thatch, scalping, puffiness.High mowing can increase thatch, scalping, puffiness.

ScalpingScalping

removal of an excess quantity of green removal of an excess quantity of green leaves.leaves. irregular contoursirregular contours excess thatchexcess thatch infrequent mowing intervalinfrequent mowing interval

Mowing thresholdMowing thresholdMowing thresholdMowing threshold

Defoliation effects are minimal when <40% Defoliation effects are minimal when <40% of leaf removed at any one time. Root loss of leaf removed at any one time. Root loss risk if otherwise.risk if otherwise.

Factors affecting frequency:Factors affecting frequency:Factors affecting frequency:Factors affecting frequency: 1) shoot growth rate1) shoot growth rate 2) environmental conditions2) environmental conditions 3) cutting height3) cutting height 4) turf use4) turf use 5) irrigation5) irrigation 6) fertilization6) fertilization 7) irradiance7) irradiance 8) temperature8) temperature 9) seedhead development9) seedhead development

Mowing FrequencyMowing Frequency

Mowing frequency increases with decreased Mowing frequency increases with decreased cutting height. A major factor in cutting height. A major factor in management and playability of sports turfs.management and playability of sports turfs.

Frequency Depends on Vertical Extension Rate (growth)Frequency Depends on Vertical Extension Rate (growth) Ex: St.Augustinegrass - vertical leaf Ex: St.Augustinegrass - vertical leaf

extension rate of 0.25 in/day. extension rate of 0.25 in/day. Mowing height = 3 inches, remove 40%, Mowing height = 3 inches, remove 40%,

mow at 5.0" Frequency = 8 daysmow at 5.0" Frequency = 8 days Mowing height = 2 inches, remove 40%, Mowing height = 2 inches, remove 40%,

mow at 3.5' Frequency = 5 daysmow at 3.5' Frequency = 5 days Mowing height = 1 inch, remove 40%, Mowing height = 1 inch, remove 40%,

mow at 1.75" Frequency = 3 daysmow at 1.75" Frequency = 3 days

Mowing scheduleMowing scheduleMowing scheduleMowing schedule

HeightHeight FrequencyFrequency 1/41/4 dailydaily 1/21/2 2-3 days2-3 days 11 4-5 days4-5 days 22 7-10 days7-10 days 44 14-20 days14-20 days

Remove Clippings When:Remove Clippings When:

interferes with use of turf (ball roll)interferes with use of turf (ball roll) excessively heavy, longexcessively heavy, long enhance disease development (Fusarium enhance disease development (Fusarium

only at high N rates).only at high N rates). - Minimal contribution to thatch - Minimal contribution to thatch

development.development.

Clippings are Free FertilizerClippings are Free Fertilizer

Clippings provide nutrients 3-6% N, 2-3% Clippings provide nutrients 3-6% N, 2-3% K, .5-1% P. K, .5-1% P.

Trash load to community. 14-25% material Trash load to community. 14-25% material sent to landfills is lawn debris.sent to landfills is lawn debris.

GrainGrain

Tendency of leaves and stems to grow Tendency of leaves and stems to grow horizontally in one direction. horizontally in one direction. - need to shift mowing pattern- need to shift mowing pattern - brush or comb prior to mowing (groomer - brush or comb prior to mowing (groomer

attachments)attachments)

Mowing PatternMowing Pattern

alternate directions, overlapalternate directions, overlap 1) reduce grain1) reduce grain 2) enhance appearance2) enhance appearance 3) differential compaction (ruts), clean-up pass3) differential compaction (ruts), clean-up pass

disease/weed movement - schedule problem disease/weed movement - schedule problem areas last. Wash mower afterward.areas last. Wash mower afterward.