These turfgrass statistics may surprise you:
- In a well maintained, thick 10,000 square foot (929 square meter) lawn there will be 6 turf plants per square inch (25.4 millimeters), 850 turf plants per square foot (30.45 square meters) for a total of 8.5 million turf plants.
- Grass plants are 75 to 80% water, by weight.
- Up to 90% of the weight of a grass plant is in its roots.
- Clippings contain nutrients useable to the grass, when left on the lawn.
- A lawn, 50 by 50 feet (15.24 by 15.24 meters) (2,500 square feet) (232 square meters) releases enough oxygen for a family of four, while absorbing carbon dioxide, ozone, hydrogen fluoride, and peroxyacetyl nitrate.
- A dense, healthy lawn prevents run-off, absorbing rainfall six times more effectively than a wheat field and four times better than a hay field.
- Turfgrass helps control pollution, trapping much of an estimated 12 million tons (10.9 million metric tons) of dust and dirt released annually into the US atmosphere.
- The front lawns of eight average houses have the cooling effect of about 70 tons (68 metric tons) of air conditioning, while the average home-size central air has only a 3 to 4 ton capacity (2.7 to 3.9 metric tons).
- As part of a well-designed and maintained landscape, turfgrass increases a home’s property value by 15 to 20 %.
- Safety-sightlines discourage intruders and heighten visibility.
- Absorbs noise and reduces glare.
In all practicality for homeowners, the water salt load is rarely critical – because you're using "drinking water." Almost all lawns and shrubs can tolerate our "drinking water" in Arizona. For people who manage large turf acreages (golf courses, parks, etc.), other water sources may be used. Water salinity may be much different (greater) from these sources than domestic water. If salt crystals appear within the middle of the lawn, you need to apply more [of the same water source] to wash the salts down.
To help increase the downward movement of water, it is best to poke holes in the lawn, using a power driven aerifier. These machines poke holes 2-3 inches in the ground. You should leave the holes open. The grass will actually fill in the holes. Don't be tempted to, or feel that you must "fill in" the holes with sand. Rake up the soil cores, or grind them up in place with a rotary mower. The open holes are more important to have to keep the salt levels tolerable.
Bermudagrass is quite salt tolerant. Tall fescue and ryegrass are moderately salt tolerant. Kentucky bluegrass is less salt tolerant than the above. Remember that salt stress causes the turf to look like it needs water! The grass will be dark blue-green in color, it will start to "wilt" and "curl" even though the soil is moist (screw driver goes in easily).
If your lawn suffers from salt stress, you can also help the lawn by mowing the turf at a higher mowing height that it is set for currently. This is not a problem for common bermudagrass, E-Z Turf, Midiron bermuda, or 99% of the improved seeded lawn type bermudagrass varieties, tall fescue, perennial ryegrass, and most lawn type Kentucky luegrass. Raising the height on Tifway (419) bermudagrass above 1-1/2 inches can often result in a scalped lawn, even if you mow three times/week. This is because most of the leaves will "migrate" to the end of the upright stems. When you mow off the tips of the stems, you can actually remove a lot of the leaves – because they are located at the tips of the stems. They exist at the tip, because of the unusually higher mowing height. Normally, when Tifway (419) Bermuda is mowed at ¾", three times per week with a sharp reel-type mower, the stems grow along the ground. The leaves are more evenly spaced across the entire length of the stem. So, less scalping occurs on Tifway when it gets mowed regularly at 3/4" or less.
Always remember, scalping a lawn is bad. Scalping a lawn that has salt stress is very bad.
To figure out how much salt is in your irrigation water, contact your local County Extension Office. They will give you an address for labs that will test samples.
