In article ,
Michael Percy wrote:
Jim Webster wrote:

by your definition of arid damn all will grow anyway

The definition I suggested was land with less than 10 inches
avg. annual rainfall. You haven't got a clue, if you think
this describes land on which damn all will grow.

G'day Michael,

Just buying in at a late stage, so I'm not too sure whose side I'm on
in this thread. :-) Whatever...

Much of northern Australia would receive around 15 to 30 inches/year,
but virtually no rain falls April through September, and Oct/Nov
storms are unreliable. The wet season is only (Dec)Jan/March, with
March being both the wettest and the driest month in many parts (i.e.
it's very unreliable too). It is considered to be the semi-arid to
sub-humid seasonally dry tropics.

Evaporation probably exceeds precipitation for at least 8 or 9 months
each year. Moreover, much of the precipitation is high intensity
so a lot of it runs off rather than infiltrates into the soil.

Evapotranspiration is high, but many trees are deciduous and the
grasses go dormant and hay off after seeding anyway as the soil
dries out.

In most of the area crops are not grown because:
1. the growing season is too short and/or unreliable;
2. soils are too poor and fertiliser is too expensive;
3. freight costs are too high due to distance and road conditions;
4. markets are too far away and returns too low.
(There are some small exceptions where irrigation is available and the
areas are close enough to "civilisation".)

The area is used for rangeland beef cattle production. If it wasn't
used for that, it wouldn't be used at all. This beef provides the
world with an excellent protein-rich food; and it doesn't deprive the
world of an ounce of grain to produce it -- the breast-beaters and
professional bleaters of the US and Europe notwithstanding.


Cheers, Phred.

--
LID