Re: mulches (was Ran Pauker lecture in Berkeley

K1MIZE@aol.com wrote:
> 
> <<Reading between the lines, if you are
> using summer spray irrigation over thick mulches, and
> allow them to dry out before the next irrigation, up
> to the first inch of water may never reach the
> plants...>>

Kurt
This is an undoubted downside of sprinkler irrigation on mulched ground.
I have heard though of people solving the problem by substituting 
soaker hoses set permanently UNDER the mulch. I am a great fan of soaker
hoses myself and now rarely us sprinklers. The latter not only waste a
good deal of precious water, but on occasion may promote infection by
foilage diseases, especially where leaf surfaces remain wet during the
night.
> 
> This is particularly true if you are mulching with peat moss (often
> recommended for azaleas and other acid-lovers), which is very difficult to
> wet, once it has dried out.

I long ago abandoned the use of peat having come to the conclusion it is
a very difficult material to handle and definitely not worth the price.
If put on as a suface mulch it dries out very easily and once dry is so
light a mere breeze can blow it away. On the other hand if put into the
soil around plant roots, sometimes even if apparently fully wetted
before use, I have known it to somehow dry out and then act as a sort of
blotting paper, actually drawing moisture away from the root zone. I
suppose it can be added to compost to augment its texturising effect on
the soil, but the same effect is more easily and successfully achieved
in my opinion with other mulch materials such as straw, woodchips, pine
needles, sawdust or rotting deciduous leaves, alone or in combination.
(If you want your mulch to have more of a feeding than just a protective
or texturising role, you simply need to add some nitrogenous material
such as well-rotted animal manure, blood and bone, alfalfa meal or even
the humble grassclippings for a quicker breakdown - marvellous way of
building a good soil)

The value of an acid mulch for Azaleas and suchlike has in my opinion
been much exaggerated. Especially if one feeds the soil only with
natural materials the pH will actually regulate itself to suit the
particular plant no matter what mulch one uses..Much more valuable to
such plants  is to find a cover for the soil that will both retain
moisture and keep the roots cool. 

 Many California natives, particularly those in the Central Valley,
although
> they apparently survive on rainfall alone, are actually very dependent upon
> the snowmelt runoff from the Sierra Nevada, which once provided a sort of
> natural irrigation during the dry months of the year in the form of a high
> water table and seasonal flooding.  Now that most of this water is being
> siphoned off for human use, many once-widespread habitats and the plants they
> supported are in danger of extinction.  Valley Oak riparian forest, in
> particular, is down to about 1% of its former range.

An argument surely I would have thought for some restraint in drawing
off so much water for those (non-native) lawns.

Moira
-- 
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata (near Wellington, capital city of New Zealand)
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