Wednesday, March 12, 2008

TURF SCIENCE: MORE GREEN FOR LESS DOUGH

New turfgrass varieties and maintenance practices produce durable green with less water and fertilizer. Read on, because it doesn't take a turf scientist to understand that this can save you and your business time and money.
Golf course managers don't see turfgrass the way landscape contractors do. On a golf course, never-ending green is the highest priority. Limits aren't placed on water, fertilizer, pesticidesor on a work crew's sweat and toil.
It's different for the contractor who plants turf and irrigation in residential and commercial settings. With most sites connected to municipal water supplies, property owners face fines if they go over irrigation limits. What's more, increasing numbers of property owners are leery about pesticides and fertilizer. Whether their concerns are justified or not, many homeowners would be pleased if you told them that you're keeping their lawn green organically that is, without artificial fertilizer or pesticides.

Conservation Means Money
Each one of these rectangular turf plots is divided lengthwise into halves receiving fertilizer and halves receiving no fertilizer. The name of this ongoing University of California study is Winter Color Enhancement for New Warm Season Grasses. (Tall fescue, of course, is classed as a cool-season turf.)
At first glance, it might seem that forgoing traditional pesticides might mean more work for you and your crew. In fact, recent findings suggest that cutting back on water and fertilizer means that you can spend less time mowing, which can translate into reduced labor costs for you and your business.
Some of these results come from the University of California's agricultural test facility near Irvine, Calif. Over the past decade or so, turf scientists have found that warm season turf varieties like hybrid Bermudagrass and zoysia do well with less fertilizer and water than is generally recommended. What's more, new types like buffalograss perform well with limited water in arid areas across the South and West.
Another key finding is that Bermudagrass and zoysia despite their warm-season reputation will stay green long into the winter if temperatures generally stay above freezing. Adding a little fertilizer in fall and winter can go a long way to maintaining what the researchers call acceptable turf quality far into the winter months.
A lot of people ignore their turf in the fall and winter, because they think it's supposed to turn brown and go dormant. But if you continue your fertilization, you can enhance and maintain that good green color throughout the winter. In the warmer-winter regions, there are a lot of turfgrass types that hold pretty good winter color if they're maintained and fertilized.

Choose Your Turf

As with other kinds of turf, a bit of knowledge about buffalograss can help save you money. If you give buffalograss lots of water and, say, four pounds of active nitrogen per 1,000 square feet per year, you're going to be mowing a lot, and you're going to have lots of clippings maybe as much as tall fescue. But what buffalograss lets you do is to drastically cut back on irrigation and not die. It will do quite well on 40 percent of the water fescue needs and still look green even at the height of summer.
Ryegrass variety is critical to successful overseeding. Be sure to choose an annual ryegrass strain Annual rye will die off and let underlying warm-season turf resume growth in the spring. Perennial rye, on the other hand, would continue to compete with the primary turf.
Zoysiagrass is another type that offers distinct advantages over more-used turf. Zoysia offers landscape professionals the chance to keep turf green with much-reduced amounts of fertilizer. With zoysiagrass, turf stays nicely green with as little as two pounds of nitrogen (pure fertilizer) per 1,000 square feet per year. To keep tall fescue green, you'd need close to six pounds applied at the same rate.
Another zoysiagrass advantage is a slow-growth rate. Compared to buffalograss, with the same amount of fertilizer and water, zoysia produces half the amount of clippingsand needs half the time to keep it trimmed. That cuts down on labor tremendously. Old-fashioned cow manure is an economical way to get nitrogen and other nutrients to turfgrass. The pungent substance is especially useful for overseeding because it promotes good seed-soil contact. Note that overseeding is also a beneficial practice in spring, where it can help fill-in gaps. Growing from seed, of course, is easier in cooler, moister climates.

Barriers to Use
With those advantages, why don't we see zoysiagrass carpeting lawns across the South and West? The answer has something to do with tradition, and something to do with growth patterns. The slow-growth rate that limits mowing for zoysia lawns is a disadvantage when it comes to planting them. Even so, the variety can be established in warmer weather with success rates that compare favorably to Bermudagrass.
With buffalograss' exceptional drought-tolerance, why isn't it much more common? The answer is that the American native is a better choice in some areas than in others.

When buffalograss is planted in high rainfall areas or when it is irrigated and fertilized, bermudagrass and other weedy grasses invade a stand of buffalograss. Buffalograss is best adapted to low rainfall areas (15 to 30 inches annually) or areas that receive thorough, but infrequent irrigation.
Also keep in mind that buffalograss does poorly in shaded sites or in sites that get heavy use. You won't see it on football or soccer fields anytime soon. Also, given artificial irrigation and nitrogen, bermudagrass and other more aggressive grasses will outgrow buffalograss.
Remember Two Things
There are two things to remember when it comes to turf. One, it pays to do a little research before you choose your turf type for a project. You may do better (for you and your clients) with one of the newer kinds. (If you aren't sure, ask a horticulturist or a turf expert at a local university extension program.)
Second, you can reduce your fertilizer and irrigation totals significantly. If you know when and how much to apply, you can keep the grass green much longer into the winter season. And that's a win-win for you and your grass.
Pre-emergent herbicides can keep crab grass in check for an entire season, but the substance must be applied before seeds sprout in winter or early springdepending on climate zone.
Fertilizer Application: How Much and When.
The amount of fertilizer to apply depends on the fertilizer product (percent nitrogen and release rate), the square footage (area) of lawn, and the purpose the lawn serves (athletic field or low-traffic lawn).
Existing Lawns: Most mature lawns benefit from about 4 pounds of actual nitrogen per 1,000 square feet per year. Grasses suited to low nitrogen and water applications (e.g., zoysiagrass and buffalograss) found that they could perform adequately with only 2 pounds per 1,000 square feet of actual nitrogen per year. Grass growing in light shade requires less fertilizer than grass growing in full sun. Turfgrasses under a grasscycling program need slightly less nitrogen; turfgrasses under heavy wear from foot traffic or sports require more nitrogen to encourage faster growth to repair damage.
Generally, a maximum of 1 pound of actual nitrogen per 1,000 square feet should be applied at one time when using a soluble chemical fertilizer. Nitrogen is the major element, so it is the element that the application rate is based on. Also, nitrogen is the most soluble element and has the most potential for burning the grass if applied too heavily. Often, less than 1 pound of actual nitrogen can be applied, but 1/2 to 1 pound of actual nitrogen per 1,000 square feet at a time is the usual recommendation. Slow-release fertilizers can be safely applied at higher rates. See the product label for specific recommendations on rates an frequency of application; the frequency can range from every 6 to 8 weeks to as long as every 6 months.
A variety of aeration equipment is available and should be used regularly as part of an integrated turfgrass-management program. A properly aerated lawn will make the most of every fertilizer application. Aeration also promotes positive root growth and helps grass resist thatch build-up. Most lawn mowers come with attachments.

Calculating application rates. To find out how much of a particular fertilizer is needed to supply 1 pound of actual nitrogen, simply divide 100 by the first number of the analysis shown on the bag. This will give you the number of pounds of the fertilizer you need to apply to 1,000 square feet of lawn area to supply 1 pound of actual nitrogen to the turf. For example, if the fertilizer analysis is 21-0-0, 100 divided by 21 = 4.76 pounds of fertilizer needed to apply 1 pound of actual nitrogen. (A similar calculation is performed for metric measurements.)

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