Re: mulches (was Ran Pauker lecture in Berkeley

In a message dated 11/16/100 3:43:39 AM EST, theryans@xtra.co.nz writes:

<< 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. >>

Hi, Moira.  Thanks for your insightful comments.  Of course people should 
practice good water use practices in our arid climate.  The truth is, 
however, that something like 90% of California's water supply goes to 
irrigate farmland, so even a sea change in urban water use practices would 
have only a small effect on overall supplies.  Drip-irrigation for 
agriculture has proven to be something of a double-edged sword.  Yes, it 
would help to conserve water if it were only used to replace flood- and/or 
sprinkler-irrigation in the areas where those are practiced.  Unfortunately, 
where they can be practiced successfully (usually on flat farmland), those 
methods continue to be used because they are cheaper.  The introduction of 
drip-irrigation has instead had the effect of rapidly expanding the amount of 
irrigated farmland, as areas (usually hilly) once considered suitable only 
for grazing are found to grow vineyards and orchards quite successfully.  I'm 
not sure what the solution is, but I think I could be a rabid 
environmentalist without too much provocation!

Kurt
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