Lawnmower Evolution Rotary mowers

Transcription

1 Proper Mowing and Lawnmower Maintenance Alan Zuk North Dakota State University Sheep were often used to maintain turfgrass in rural areas through the 1920s. Lawnmower Evolution Rotary mowers s -30 s s -60 s Characteristics: Best used for turf to be maintained at a height greater than 1 inch. Rotary mowers are easily serviced, and are relatively inexpensive to maintain. Push-Mower html 1960 s -70 s s -Present 1

2 Mowing Do a better job at cutting tall grass and seed stalks than reel mowers. The blade tip speed on a 20 inch walk behind rotary mower running at 3600 rpm is approx. 214 mph or 314 feet per second. Arm Sail Throw rocks and other items, can be dangerous to bystanders. Rotary mower blade Mowing Rotary mower blade maintenance Sharpen blades after every eight hours of use Sharpen at a 30 o angle 20 o will cut but cutting edge will chip easily 40 o is too blunt Sharpen blade on top side only Attach blade to mower with sail positioned upward Discard blade when arm width wears down to one inch Mowing Dull mower blades cause: A reduction in turfgrass quality An increase in disease susceptibility A decrease in shoot density A decrease in water use rates A decrease mower fuel efficiency by 22% Steinegger et al.,

3 One-third rule: Mowing Frequency A general rule of thumb for determining mowing frequency. Remove no more than 1/3 of the shoot height in one mowing. Examples: Mowing height Mow when a) 1 inch 1.5 inch 0.5 inch (1.5 x 0.3 = 0.5 inch; = 1.0 inch) Length removed One-third rule: Mowing Frequency Do not remove more than 1/3 of the blade when mowing. Bagging is not necessary when following this rule. Grass clippings are comprised of 75-85% water and contribute little to thatch if mowing is conducted with proper frequency. Clippings return the equivalent of 1 lb. nitrogen per 1000 sq. ft. by the end of the season. b) 3 inches 4.5 inches 1.5 inches (4.5 x 0.3 = 1.5 inches; = 3.0 inches) Mowing Frequency Mowing Frequency If you do would like to reduce your mowing frequency, should you maintain a high or low-cut turf? Assume that the canopy of turf (a) and (b) grows at an average rate of 1/4 inch per day and 1/3 of the blade is removed at each mowing. If turf (a) is maintained at 1 inch, it would have to mowed after 2 full days of growth: = 1.5. On the other hand, if turf (b) is maintained at 3 inches, it would have to be mowed after 6 full days of growth: = 4.5. Mowing High Mowing Low Turf mowed higher is mowed less often! This is contrary to many homeowners beliefs. 3

4 Mowing Height Lowering the mowing height on a turf area results in: Reduced carbohydrate synthesis. Reduced leaf width. Reduced root growth rate and total root production. Reduced growth of lateral stems. Increased amount of chlorophyll per unit area. Maximize rooting and lateral spread by mowing high. Be sure that the discharge chute faces out/away when mowing around stationary objects. 4

5 Also, be sure to discharge clippings away from unmowed grass as you mow. Is it okay to mow wet grass? Soil Moisture and Compaction Change mowing directions each time you mow to avoid rutting your lawn. East to west North to south Lower right to upper left Lower left to upper right. Daniel, W.H. & R.P. Freeborg,

6 Heat tracking damage Lawnmower rutting can even occur on dry soil if mowing directions are not alternated. Tracking damage caused by mowing while the turf is subjected to heat and drought stress. Mowing on frosted grass Lawn Patterns Tracking damage caused by mowing while frost on turf is visible. Achieved by bending turf in opposite directions as you mow. 6

7 Lawn Patterns Lawn Patterns -ballpark-designs.htm Intricate lawn patterns are created by brooming the turf. Lawn Patterns Mow a straight line with your mower Follow that line closely on the return pass Mow twice if striping tall grass or attach a rubber mat to your mower for greater effect. Fuel Regular unleaded should be used in small engines. Ethanol-based gasoline can be used unless the owners manual instructs you not to. Do not store your mower for long periods with ethanol-based fuel in the tank. Ethanol will varnish the carburetor over time. Ryegrass is the most conducive turf for lawn patterns because of its shiny backside Other turf species can be striped too, especially if maintained at a short height 7

8 Air Filter Maintenance Cleaner New/ html Wash sponge pre-cleaner with dish soap and water. Wring out dry. Wrap in a cloth rag and repeat. Apply a coat of air filter oil. Do not use compressed air to clean a paper filter. Tap paper element on the ground to knock out dust. Apply a coat of air filter oil. Clean and gap spark plugs annually or as needed. 8