Study Finds Benefit of Leaving Clippings on Lawns

Discussion in 'Lawn Mowing' started by ECHOTURF, Jun 30, 2003.


    ECHOTURF LawnSite Member
    from usa
    Messages: 40

    Just some information I got in an e-mail from the lawn care industry. This makes me feel really good when I'm mulching everyday. -- :D --

    A small change in the way lawns and parks are groomed might improve landscape ecosystems and soil and reduce carbon dioxide in the air, all while saving money usually spent on maintenance, a recent Colorado State University study shows.

    "The study shows that if lawn clippings are left on grass after it is mowed, nitrogen and carbon, two nutrients important to plants, increase within the soil," said Yaling Qian, lead researcher on the project and an assistant professor in the Department of Horticulture and Landscape Architecture. "This also reduces the amount of fertilizer a landscape needs and reduces the emission of greenhouse gases from the landscape, which improves the environment."

    Grass landscapes, such as that on lawns, parks and golf courses, produce a large amount of clippings every year. But clippings are often removed when turf grass is mowed, and clippings contain a major amount of nitrogen that can be reused by the landscape.

    In fact, leaving clippings on landscapes and reducing typical nitrogen fertilizer applications actually improves air and soil quality, according to the study, which modeled long-term effects of leaving clippings on landscapes.

    When clippings are left on the landscape as an annual practice, 25 percent less nitrogen fertilizer can be applied between the first 10 years on established turf, 33 percent between 11 and 25 years, 50 percent between 25 and 50 years, and 60 percent after 50 years. The turfgrass is not harmed by the lower amounts of fertilizer because the nitrogen from the clippings becomes available. This reduction in fertilizer also reduces the leaching of nitrates into drinking water and the emission of gaseous nitrogen into the atmosphere. Returning the clippings to the landscape for 10 to 50 years also increases the amount of carbon stored in the soil by 11 percent to 25 percent when it is fertilized with a high amount of nitrogen, about 150 kilograms a year.

    Reducing nitrogen applications to 75 kilograms a year and leaving the clippings on the landscape increased carbon storage in the soil by up to 59 percent after the turf was established. Carbon dioxide emission is reduced by about 1 ton per acre per year when clippings are left on landscapes, considering the combined impacts of clipping management on soil carbon and fertilization requirements.

    Source: North Forty News

    Monday, June 30, 2003
  2. tiedeman

    tiedeman LawnSite Fanatic
    from earth
    Messages: 8,745

    I just read that about 15 mins ago...the funny thing is that I have known about "grasscycling" from the PLCAA for years. That is all that they promote. It's hard to sell the customers on it though
  3. mtdman

    mtdman LawnSite Gold Member
    Messages: 3,143

    If you don't give them the option of taking the clippings away, it's easy to sell them on it! :D
  4. CMerLand

    CMerLand LawnSite Senior Member
    Messages: 394

    Im all for grass cycling and as others have mentioned the idea has been around for years. And when growing under normal conditions I agree, it is absolutely possible to provide a quality cut while leaving zero visible clippings on the lawn. Normal conditions would include regularly scheduled mowings of no more then a week, proper applications of slow release fertilizer, and cutting when the turf has dried completely to allow for best dispersal.

    However, after the constant and continued rain over the past two months and the outrageous growth rate of overfertilized lawns, the lawns of those who do not collect clippings still have a layer of long dried grass clippings that just lay across the lawn. Because these clippings have now dried completly they do not contain the moisture to allow for them to break down quickly, and end up being carried into the homes on the kids or pets feet.

    While cutting during the wet weather, multiple cuttings with our Toro Z, would lead to nothing more then a heavy layer of clippings and clumps. We would then vacumn up those clumps and clippings using our walker leaving a client with a completed job that looks just as good as any other week of the year.

    We would tell our clients to look at the competition lawns if they wondered why they pay more per cut then the neighbors, with the clumps and the trails of grass throughout the lawn. In fact we have picked up clients specifically because we have the abilty to pick up the clippings and can offer that to our clients.

    Yes Im all for grass cycling, but extreme conditions may require the clippings to be removed. And being able to fill that niche has added clients to our routes.

  5. xpnd

    xpnd LawnSite Senior Member
    Messages: 378

    Have been mulch mowing since we've been in business for over eleven years. Different types of turf mulch better than some. St. Augistine disappears into nothing wet or dry. Bermuda is tougher but with a little extra work when it is wet, the crew can make it look just like a bagged lawn. I have found Fescue to be nearly impossible unless it is in drought stress. Fescue retains so much water that even when it is not wet from dew or rain it still clumps.

    We always give the customer the choice to have the lawn bagged but at a significantly higher cost due to the extra time involved. THe bags are also left at the job site in a location agreed upon with the customer. Most are amazed at how many bags are actully produced when the lawn is legitmately bagged when the bags are emptied as soon as they are full. I am always left wondering how a maintenance company can bag a lawn (5-8K) and only empty the bag one time when they get back to the trailer. I guess they have the newer more envinronmentally friendly mowers that utilize grass clippings as fuel.

    A lawn that is mulched will after one year have a better appearance than a bagged lawn and require roughly 10% less fertilizer than recommended.
  6. yardmonkey

    yardmonkey LawnSite Senior Member
    Messages: 341

    I always mulch-mow. Have just dropped my only 2 customers that insisted on having grass bagged.
  7. ElephantNest

    ElephantNest LawnSite Bronze Member
    from La.
    Messages: 1,878

    Something like 60% of needed nutrients come from mulching, as I stated in a previous post. But grasses like St. Augustine need dethaching regularly if mulched. Will survive and do ok without it, but over time will easily develop a weed problem and be prone to disease. Dethach at least once a year, you'll notice a big difference.
  8. the scaper

    the scaper LawnSite Senior Member
    Messages: 690

    i've always mulch mowed with my x-mark z rider. i've known for quite some time that clippings are some of the best fertilizers you can put on a lawn. the only time i've seen clippings on top of the lawn are on bi- weekly customers , if they complain i use that as a opportunity to convert them to weekly. i read an artical about how out in california they clog the dumps each year with enough clippings to fertilize the entire state. of coarse thats california though, i'm sure there's some of that good ole liberal wisdom behind it somewheres. ;)
  9. CMerLand

    CMerLand LawnSite Senior Member
    Messages: 394

    Elephant nest said:

    Something like 60% of needed nutrients come from mulching, as I stated in a previous post. But grasses like St. Augustine need dethaching regularly if mulched.


    i've known for quite some time that clippings are some of the best fertilizers you can put on a lawn.

    If you guys are going to praise the value of grass cycling then you better have your facts straight or your only going to defeat your own cause when you run into a client that has read up on the matter. And with the internet today, that research is much easier then ever. I would like to read that research article that states that 60% of the needed nutrients come from mulching turf grasses. The only nutrient returned to the lawn from grass-cycling is nitrogen, there is no signifcant potassium or phosphorus stored in the leaf blade, only the nitrogen taken up from fertilizer applications is prevelent to any major level.

    Secondly, the whole theory of grass cycling is that the small leaf blades will rapidly break down because of the high moisture and nitrogen content. Nothing about leaf clippings has anything to do with thatch and will not increase the amount of it. Thatch is the dead and decomposing layer of dead turf plants, stems rhizomes and stolons caused by overfertilization, poor watering or other cultural practices that get the turf ecosystem out of balance. The most signicant cause of thatch is the the type of grass and its habit of growth. Southern turf grasses such as st augustine and zoysia are more susceptiple because of their growth habits, but grass clippings, if done with the intention of grass cycling will contribute noting to thatch in a properly managed lawn.

    Get your facts straight gentlemen before you spout them to an uneducated public.

  10. ElephantNest

    ElephantNest LawnSite Bronze Member
    from La.
    Messages: 1,878

    Uh....I have my facts straight. I will look for the article that will prove my words. I've lived and worked with southern grasses for years and years, I know what I'm talking about. But of course, there's always someone like you "Who knows it all". And thank God, too, for where would we peons be without wisdom and tact such as yours?

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