Re: lawn management (was Ran Pauker lecture in Berkeley
david feix wrote:
>
> Kurt, I think the shade is the bigger factor in
> keeping things green longer into the dry season.
Shade is undoubtedy an important factor in the effective survival of
plants in hot weather. In a vegetable garden it can be easily be
observed during the heat of the day in the different times it takes
leafy crops take to wilt. Where there is shade from something like a
building or a distant tree they spend a great deal more time in summer
turgid, which means far more time photosynthesising and therefor
actively growing. Two different factors are obviously at work, the
longer retention of moisture in the soil for the roots and the
preservation of sufficient moisture in the air around them to prevent
excessive transpiration.
As far as the roots are concerned, they can certainly be helped by
anything (such as a mulch) which will protect the soil surface from
heating and dessication, but it is also usually very important to
encourage deep rooting which will often allow them to tap moisture
surviving in the lower soil levels.
Experiments have conclusively shown that to achieve deep rooting in lawn
grass the conventional cutting to about 1" is way too short and simply
does not allow enough leafage to grow good deep roots. Raising the cut
to 3" is apparently ideal, but even a doubling of height can work
wonders for grass vigour as we have proved ourselves. Incorrect watering
methods though can however nullify many of the good effects of a larger
blade area. Frequent and shallow applications just encourage
near-surface rooting (the more one waters, the more one needs to water).
Far better and more lasting effects come from infrequent but much more
adequate waterings, which penetrate to and replenish the deeper soil
reservoir. If it was sufficiently adequate even a monthly application
could be a pretty good tactic for survival I think.
> > Amazing to me, too. Here in the Central Valley of
> > California, I would be
> > willing to bet that there is virtually NO lawn,
> > including one of Bermuda or
> > St. Augustine grass, that could be maintained with
> > only monthly irrigation.
> > Kept alive, perhaps, but not attractive. Lawns here
> > are generally maintained
> > in summer with a ONCE OR EVEN TWICE DAILY irrigation
> > regime. You can get by
> > with every other day, or even skip two days every
> > once in a while, but the
> > appearance of your lawn will suffer as a result.
The idea that anyone could be prepared to go to all this effort and
waste of resources to maintain a green lawn of a grass (bluegrass was
mentioned somewhere) apparently totally unsuited to the climate, fills
me with amazement. There are all sorts of other ways of designing an
attractive garden surely which would not require such faithful tending
and, even if one still wants a lawn, species which will do the job
pretty adequately without all this tremendous requirement for water and
tending.
Unfortunately we are very much creatures of habit and this can extend to
what we grow as well as to other aspects of our lifestyle. And not only
among gardeners, for instance, it took several killer droughts to
persuade pastoralists here in parts of our South Island to adopt the
suggestions of the Agricultural Department for substituting their
traditional pastures with more appropriate dryland species.
Moira
--
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata (near Wellington, capital city of New Zealand)
