Yard Waste Management
As much as one third of the solid waste that goes into New Mexico
landfills comes from grass clippings, tree leaves, and other landscape
waste. These wastes contain valuable nutrients, which are removed from the
landscape when they are discarded. They take up landfill space, increasing
service costs and taxes to pay for their removal. Additional fertilizer
expenses are incurred to partially replace the nutrients lost when the
landscape waste was removed from the site.
The following waste reduction plan was developed by New Mexico State
University is Cooperative Extension Service. It is designed to reduce
landscape waste entering the landfills, protect the environment, and
improve the quality of New Mexico landscapes.
Two major sources of landscape waste are grass clippings and tree
leaves. The lawn care and leaf care management plans outlined below will
help you reduce the amount of fertilizer you use on the lawn, have a
healthier lawn, and to use your grass clippings and leaves rather than
sending them to the landfill.
Lawn Care Plan
MowingMowing, along with irrigation and fertilization, is one of
the most basic turfgrass cultural practices. It involves periodically
removing some of a portion of the turfgrass aboveground plant material
(leaves and stems), primarily to increase turf density. This, in return,
improves the areas appearance or provides a uniform playing surface for
certain sports. Table 1 gives the preferred mowing height of commonly used
cool and warm season turfgrass species in New Mexico.
| Table 1. Mowing heights for warm and cool season
turfgrass species. |
|
| Grass species |
Mowing height (in.) |
|
| Cool season |
|
| Fine fescues |
0.5 1.5 |
| Kentucky bluegrass |
0.75 2 |
| Perennial ryegrass |
0.75 2 |
| Tall fescue |
1.5 3 |
|
|
| Warm season |
|
| Seeded Bermudagrass |
1 2 |
| Hybrid Bermudagrass |
0.5 1.5 |
| Buffalo grass |
1.5 4 |
| Seashore paspalum |
0.25 1.5 |
| St. Augustine grass |
1 3 |
| Zoysiagrass |
0.5 2 |
|
Turfgrass areas should be mowed frequently enough to never have more
than 30% of the aboveground tissue removed. For example, if a turfgrass
areas preferred mowing height is 1 inch, it should be mowed when a height
of 1.5 inches is reached. If the desired mowing height is 2 inches it
should be mowed at 3 inches. If the proper mowing frequency is followed,
clippings can be left on lawns, returning valuable nutrients to the grass
plants. Clippings contain approximately 4% nitrogen, 0.5 to 1%
phosphorous, and approximately 2% potassium as well as essential
micronutrients. Grass clippings returned to the lawn can reduce fertilizer
use by 25%.
If turf is mowed at the proper height, clippings will not contribute to
thatch accumulation. Thatch describes a mixture of completely decomposed,
partly decomposed, and freshly deposited organic matter accumulated at the
plant and soil interface. If too much thatch accumulates, turf quality may
be reduced, because thatch interferes with water and nutrient availability
and can be host to disease organisms.
Three types of mowers are commonly used for mowing turfgrass: flail,
reel, and rotary. The mowing component in a flail mower consists of
numerous small knives hinged to a horizontal shaft. The shaft rotates, and
the knives cut any kind of vegetation and debris to a finely ground mulch.
Flail mowers are used on infrequently mowed turfs where appearance does
not play a major role (roadsides). Reel mowers use a shearing action with
the grass blade caught between the rotating reel and the bed knife. They
provide the highest quality of cut of all three types of mowers and are
best suited for very low cut areas.
Rotary mowers are the primary type of mower used on most home
lawns. A horizontally rotating blade cuts the grass. Models range in
size from small push behind units to large riding units that mow large
areas in a short period of time. Recent advancements in rotary mower
technology led to the development of mulching mowers. Modifications of
rotary mowers include specially designed mulching blades and/or
restrictions on the grass discharge ports. These modifications produce
very small clippings that can be easily decomposed within the turf canopy
and on the soil surface. Clippings do not have to be collected and sent to
a landfill.
WateringProper watering is essential to a healthy lawn.
Irrigation should be applied deeply and infrequently. Frequent and shallow
watering encourages a shallow root system that makes a lawn more
susceptible to drought and grub damage.
The amount of irrigation water to be given to the turf and the
irrigation frequency depend on the type of grass and the soil type. Grass
on clay soils generally needs to be watered less frequently because of the
greater water holding capacity of these clayey soils. Sandy soils drain
faster and have to be watered more frequently in smaller amounts.
Warm season grasses, such as Bermudagrass and Buffalo grass may need only 1
inch of water every 5 days, while cool season grasses such as Kentucky
bluegrass, perennial ryegrass, and tall fescue, have to be watered 1 inch
every second to third day. The best time to water is early morning,
because water pressure is usually high and no water is lost through
evaporation, as compared to watering midday when temperatures are high.
FertilizingAn attractive, stress tolerant lawn must have an
adequate supply of mineral nutrients available in the soil. Turf grasses
are most responsive to nitrogen, which promotes shoot growth and enhances
green color. Fertilization with phosphorous and potassium should be based
on a soil test. For slow and even turf growth, using a slow release
fertilizer, such as sulfur coated urea or urea formaldehyde, is
recommended. Table 2 lists nitrogen rates per growing month and
application dates for a medium maintenance level lawn.
| Table 2. Nitrogen requirements per growing month
and application dates for different turfgrass species in a medium
maintenance level lawn. |
|
| Grass species |
lb nitrogen/1000ft2 /growing
month |
Application dates |
|
Cool season Fine
fescues |
0.25 0.5 |
mid April, mid September, beginning of November |
| Kentucky bluegrass |
0.75 1 |
|
| Perennial ryegrass |
0.75 1 |
|
| Tall fescue |
0.5 0.75 |
|
|
|
|
Warm season Seeded
Bermudagrass |
0.75 1.5 |
mid May, mid June, beginning of August, mid September |
| Hybrid Bermudagrass |
0.5 1 |
|
| Buffalo grass |
0.25 0.5 |
mid May, mid August |
| Seashore paspalum |
0.25 0.5 |
mid May, mid June, beginning of August, mid September |
| St. Augustine grass |
0.5 0.75 |
every 8 wks in growing season |
| Zoysiagrass |
0.25 0.5 |
mid May, mid August |
|
Leaf Management PlanFallen tree leaves also contain nutrients
that can be used by turfgrass and other plants. Leaves left on the
lawn for extended periods can diminish the amount of light reaching the
grass and may cause the lawn to thin. In lawns covered with as much as 5
to 6 inches of leaf litter (ankle deep), the leaves may be shredded
by mowing and left to decompose without affecting the turf quality. If the
fallen leaves are even deeper, remove the leaves. It is important that the
leaves, shredded or unshredded, do not cover the lawn for a long period,
diminishing the light received by the grass.
It is not necessary to bag fallen leaves for disposal in a landfill.
They may remain on the lawn to return or they may be removed to mulch
flower and vegetable gardens. A mulch is any material that covers the soil
surface and conserves water, moderates soil temperatures, discourages
weeds, and reduces soil erosion and crusting. Shredding the leaves or
running the lawn mower over them will make them decompose more quickly,
create a more uniform mulch, and reduce their tendency to blow away.
Tree leaves also may be composted to create an organic soil amendment
to improve garden soil. Compost is decomposed organic material that looks
like soil. Composting may be done in piles or bins of simple or elaborate
design. To compost fallen leaves, mix the leaves with nitrogen containing
material, such as fresh vegetable waste from the kitchen, green grass
clippings, or manure. Turn and water the compost to speed decomposition.
The leaf mold made by composting yard waste may be used to enrich the
soil of gardens or may be applied as a top dressing to lawns. As a soil
amendment it will improve the drainage characteristics of clay soil and
increase the water holding capacity of sandy soil. For additional help on
composting click on this link
Techniques/1pgcompost.htm or go to
site map and find additional composting
pages.
02/01/2009
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