potency@violet.berkeley.edu (Tom Slone) (05/24/89)
In article <8323@pyr.gatech.EDU> steve%revolver@gatech.edu writes: >In article <1989May23.190505.18229@utpsych.toronto.edu+ raymond@psych.toronto.edu (Raymond Shaw) writes: >+Would the lawn produce more oxygen (which I presume is good for the environment) >+if I didn't mow it, and just let it grow? > You can stop worrying. Grass is biomass and perennial. It draws its >energy and nutrients from the sun and the soil. When it dies, the elements >return from whence they came. No net gain or loss in oxygen. The net loss to the environment has already happened when the lawn was installed in the first place: - Loss of native species (including native grasses) and habitat - Loss of species diversity (when the ecosystem was changed to a monocrop) - Reduction of biomass (from multi-foot high trees and shrubs to inch high grass) - Consequent loss of carbon bank, released as CO2 to the atmosphere - Potential releases of poisons to the environment from lawn maintenance chemicals and their production potency@violet.berkeley.edu {decvax|hplabs|ihnp4|decwrl|nbires| \ sdcsvax|tektronix|ulysses}!ucbvax!violet!potency
ajw@stout.cis.ufl.edu (Andy Wilcox) (05/31/89)
In article <24792@agate.BERKELEY.EDU> potency@violet.berkeley.edu (Tom Slone) writes: > >The net loss to the environment has already happened when the lawn was >installed in the first place: There are some important steps you can follow to make things better for the environment. * If you mow your lawn, don't use a gasoline powered mower. * If possible, blow your grass over your yard, and let it decompose there. Raw grass contains a sizeable portion of nitrogen that is returned to soil by this method. Leaving grass on the lawn does not cause thatch, which is most commonly caused by over fertilization. * If you bag your grass, be sure to compost it, and spread it back over your yard in the next season. Again, your lawn will love the nitrogen boost. --Andy
rbc@cuuxb.ATT.COM (~XT6511100~Rick Clark~C24~H15~6011~) (06/01/89)
In article <20388@uflorida.cis.ufl.EDU> ajw@manatee.cis.ufl.edu (Andy Wilcox) writes: > * If possible, blow your grass over your yard, and let it decompose > there. Raw grass contains a sizeable portion of nitrogen that is > returned to soil by this method. Leaving grass on the lawn does > not cause thatch, which is most commonly caused by over > fertilization. I do not bag my clippings, and I have a dog that "selectively fertilizes" my lawn, so I have a some good first hand data on thatch vs. fertilization. FACT MODE ON: On my lawn (northern Illinois clay in almost full sun): No fertilizer == thatch. Good fertilizing == no thatch. Over fertilizing == no grass. FACT MODE OFF, PONTIFICATION MODE ON: Grass clippings return nitrogen to a dense stand of grass. Grass clippings speed the thatching rate of a sparse stand of grass without returning much nitrogen to the soil (it is released to the air instead of the soil by the sunlight exposure). Partial shade also beats thatch in my lawn. I suspect watering copiously and regularly would too. I think manicured lawns are silly for this part of the country too, but I also think it is important not to spread misinformation, regardless of the cause. -- =Richard B. Clark Lisle, IL ...!{att,lll-crg}!cuuxb!rbc OR cuuxb!rbc@arpa.att.com
ries@arcturus (Marc Ries) (06/01/89)
In article <20388@uflorida.cis.ufl.EDU> ajw@manatee.cis.ufl.edu (Andy Wilcox) writes: >In article <24792@agate.BERKELEY.EDU> potency@violet.berkeley.edu (Tom Slone) writes: >> >>The net loss to the environment has already happened when the lawn was >>installed in the first place: Last time I heard, concrete doesn't provide oxygen to the atmosphere. >There are some important steps you can follow to make things better >for the environment. There are. Only lets get them CORRECT! > * If you mow your lawn, don't use a gasoline powered mower. Let's be more specific. Use a push mower. An electric mower requires juice from the utility Co. which has to be produced somehow (burning coal, gas, nuclear, etc.). > * If possible, blow your grass over your yard, and let it decompose > there. Raw grass contains a sizeable portion of nitrogen that is > returned to soil by this method. Leaving grass on the lawn does > not cause thatch, which is most commonly caused by over > fertilization. Unfortunately, raw "grass" clippings actually USE UP available soil nitrogen in the process of decomposition. It's crops like CLOVER (that turn fixed nitrogen [nitrogen in the soil that other plants can't utilize] into free nitrogen [nitrogen that plants can utilize]) that release their accumulated nitrogen in the decomposition process. RTFM 8-) You should actually ADD free nitrogen so that the decomposing grass does not deplete the nitrogen in the soil. While letting grass clipping stay in the grass does not guarantee a thatch problem, it won't help. Thatch is a layer of dead organic matter, not yet decomposed, that hinders the infiltrations of air, water, and nutrients to the grass roots. Mechanical aeration or increased microbial activity (to decompose the thatch) will help control "thatch". > * If you bag your grass, be sure to compost it, and spread it back > over your yard in the next season. Again, your lawn will love the > nitrogen boost. It may help the soil by providing organic matter to aerate the soil and improve microbial activity, but composted "grass" does NOT give your lawn a nitrogen "boost"! Marc Ries <somewhere>!ries "PHOTOVOLTAICS: safe/clean Electricity from the SUN"
rbc@cuuxb.ATT.COM (~XT6511100~Rick Clark~C24~H15~6011~) (06/03/89)
In article <1785@spp2.UUCP> ries@spp2.UUCP (Marc Ries) writes: >In article <20388@uflorida.cis.ufl.EDU> ajw@manatee.cis.ufl.edu (Andy Wilcox) writes: >> * If possible, blow your grass over your yard, and let it decompose >> there. Raw grass contains a sizeable portion of nitrogen that is >> returned to soil by this method. Leaving grass on the lawn does >> not cause thatch, which is most commonly caused by over >> fertilization. > > Unfortunately, raw "grass" clippings actually USE UP > available soil nitrogen in the process of > decomposition. It's crops like CLOVER (that turn Are you sure about that Andy? I recall from my MSU crop and soil science courses that straw decomposition is a net consumer of nitrogen but that hay was a net contributor. (They didn't specify clover or timothy). I suspect the fresh clippings are analogous to hay and the thatch is analogous to straw (clippings with the nitrogen decay products already leached into soil and air by rain and sun). If you can compost the clippings or get them into dense shade at roots of good grass to rot quickly, I think they do return more nitrogen than they consume from the decay process. They do NOT return more nitrogen than they originally took from the soil (like clover can), but it is better than not returning anything. -- =Richard B. Clark Lisle, IL ...!{att,lll-crg}!cuuxb!rbc OR cuuxb!rbc@arpa.att.com
jma@abel.UUCP (Jeff Abrahamson) (06/08/89)
Several people have debated the pros and cons of fertilizer w.r.t. thatch. Could someone clue me in on why you don't want thatch? Unless you cut your grass quite short (which wastes water in all but the wettest areas), you shouldn't see much brown through the green. And thatch makes for a softer lawn. When I walk (--> barefoot) or lie on grass, I much prefer to see grass and thatch than topsoil (as I do on some well-raked lawns). -- ---------- Jeff Abrahamson jma@abel.uucp, abel!jma@manta.pha.pa.us UPenn Mathematics jma@grad1.cis.upenn.edu Bicycle Coalition of the Delaware Valley
rbc@cuuxb.ATT.COM (~XT6511100~Rick Clark~C24~H15~6011~) (06/09/89)
In article <415@abel.UUCP> jma@abel.UUCP (Jeff Abrahamson) writes: > > Several people have debated the pros and cons of fertilizer >w.r.t. thatch. Could someone clue me in on why you don't want thatch? > > Unless you cut your grass quite short (which wastes water in >all but the wettest areas), you shouldn't see much brown through the >green. And thatch makes for a softer lawn. When I walk (--> >barefoot) or lie on grass, I much prefer to see grass and thatch than >topsoil (as I do on some well-raked lawns). >-- >---------- >Jeff Abrahamson jma@abel.uucp, abel!jma@manta.pha.pa.us >UPenn Mathematics jma@grad1.cis.upenn.edu >Bicycle Coalition of the Delaware Valley Well, there is thatch, and then there is THATCH. This is more of a problem in parts of the country drier than your Delaware Valley. Thatch in good, barefoot turf you can only see by looking carefully deep in between the blades. THATCH, on the other hand makes the lawn look like thin, green streaks on a background of pale brown that glares in the sunlight. In bad cases, the grass retreats to little islands of struggling green, and there are many pock marks as big as your fist with no grass at all. THATCH is definitely not pleasant to walk or lay on. The grass gets into lumpy tufts. The grass blades develop stiff, protective sheathes that poke tender skin. the ground gets compacted under the thatch without grass roots to aerate it. The grass is not dense enough to maintain a cool, moist microclimate. It feels like it reflects nearly as much heat on a pedestrian as a concrete sidewalk. Ants and large weeds however, think THATCH makes a major improvement in a lawn. -- =Richard B. Clark Lisle, IL ...!{att,lll-crg}!cuuxb!rbc OR cuuxb!rbc@arpa.att.com