permaculture

["Lawrence F. London, Jr." <london@sunsite.unc.edu>]

http://sunSITE.unc.edu/london   InterGarden   
london@sunSITE.unc.edu   llondon@bellsouth.net

Maybe mowing lawns, pastures and hay crops the traditional way
with sharp scythes (resharpened in the field as needed) would
put more people to work, reconstitute said work force, provide
more focus on natural agricultural methods and reduce the 
pollution described below.
LL
---------- Forwarded message ----------
Date: Wed, 22 Apr 1998  8:17 -0600
From: "Kephart, Kevin          PltSc." <KEPHARTK@mg.sdstate.edu>
To: forage-mg@web.CSS.ORST.EDU
Subject: Grass Gas
-
Colleagues:
I found this information on the Discovery Channel web site last night.
Kevin
-
Study: Grass is
               Environmentally Unfriendly

               Lawns and grasslands release vast quantities of
               pollutants into the air, according to one of the first
               studies of gaseous emissions from grass and clover.

               Firing up the mower and cutting the grass will just
               make things worse.

               Scientists from Australia's CSIRO Research Institute
               and Monash University have found that emissions of
               chemicals increase approximately 100-fold after
               grass is cut, and take hours to reduce to their original
               levels.

               Cattle grazing or trampling will have a similar effect
               to mowing, increasing emission rates from grass.

               Scientists believe that some of the additional gases
               released by cut grass are natural antibiotics, which
               act to disinfect the wound site. Gases released by
               grass include the volatile organic compounds
               methanol, ethanol, propanone and butanone,
               according to CSIRO.

               This study has shown that grasslands around the
               world may be one of the biggest sources of the
               gases methanol, and perhaps ethanol, in the
               atmosphere.

               "It's not just cars and industry, or lawnmowers
               themselves, that cause air pollution," says Ian
               Galbally, from the CSIRO Division of Atmospheric
               Research.

               "Plants release highly reactive hydrocarbons that can
               add significantly to photochemical smog problems,"
               Galbally says.

               To measure emissions of these air pollutants from
               grass, scientists from Monash and CSIRO set up a
               transparent chamber in a grass paddock in
               Gippsland, south-eastern Victoria. Over two years,
               the scientists collected and analyzed gases released
               by the grass to learn how emissions are affected by
               variations in temperature and light intensity, and by
               drought.

               Although grasslands and pastures cover a quarter of
               the Earth's land surface, this study is one of the first
               of emissions from grass and clover. "Emissions from
               grass are at their greatest in warm weather and at
               around midday, when sunlight is most intense," says
               Galbally. "No gases are released at night."

               Wayne Kirstine from the Gippsland campus of
               Monash University conducted the research with
               Galbally.

Kevin D. Kephart
Associate Professor of Plant Science
Plant Science Department
South Dakota State University
Brookings, SD  57007

email: kkephart@abs.sdstate.edu
Tel: (605) 688-4751
FAX: (605) 688-4452