Michael Percy writes

I do not mean Sahel, but a good part of Sahel must be arid.
By all means post how much beef is produced from it if you know.

I've been to parts of it, and similar areas round kenya-Tanzania. They
are almost all pastoralists (like the masai) although in wetter areas
some grain is grown.

It's not the sort of place that does government records, and even if
they did I wouldn;t believe them.

--
Oz
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Michael Percy wrote in message
...
Jim Webster wrote:


Michael Percy wrote in message
...
Oz wrote:

Michael Percy writes

My argument stands. Sahara is very big, but even then it must be
sustaining a pitifully small cattle herd.

Remember most of n.africa was the breadbasket of rome.

You are probably thinking of the semi-arid or sub-humid parts of
Algeria and Tunis, but we are talking about arid land.

remember it didn't use to be arid

I leave that discussion to you and the previous poster.
It is irrelevant to my argument.

by your definition of arid damn all will grow anyway so the whole
argument becomes nugatory


--
Jim Webster

"The pasture of stupidity is unwholesome to mankind"

'Abd-ar-Rahman b. Muhammad b. Khaldun al-Hadrami'


Mike

Michael Percy wrote in message
...
Oz wrote:

Michael Percy writes

I do not mean Sahel, but a good part of Sahel must be arid.
By all means post how much beef is produced from it if you know.

I've been to parts of it, and similar areas round kenya-Tanzania.
They
are almost all pastoralists (like the masai) although in wetter
areas
some grain is grown.

It's not the sort of place that does government records, and even if
they did I wouldn;t believe them.

Of course livestock must be of extreme importance to people living
from arid
land. They can't grow a crop! My point is if the land is arid, it
will
carry only a low density of people and livestock. If as I suspect only
a
few % of all beef cattle feed is produced from arid land, it seems
silly
to seek justification THERE for the use of ressources for beef
production.
One does that much better by pointing to the quite efficient use of
ressources in mixed farming livestocking system in more rainfed
areas.

check with the Israeli's, the Negev and much of Israel is arid but it
doesn't stop them growing an awful lot of crops on it.
Indeed the whole of the top end of the Persian Gulf is arid but
civilisation developed in Mesopotamia

Arid never stopped anyone provided you could ship water in somehow.

--
Jim Webster

"The pasture of stupidity is unwholesome to mankind"

'Abd-ar-Rahman b. Muhammad b. Khaldun al-Hadrami'


Mike

Michael Percy wrote in message
...
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.

and have been told that ten inches isn't arid, see Oz's post.
Also rainfall doesn't define fertility, available water determines
rainfall, the fertile cresent has a pretty low rainfall, as has the Nile
valley.


--
Jim Webster

"The pasture of stupidity is unwholesome to mankind"

'Abd-ar-Rahman b. Muhammad b. Khaldun al-Hadrami'

Michael Percy writes

Of course livestock must be of extreme importance to people living from arid
land. They can't grow a crop! My point is if the land is arid, it will
carry only a low density of people and livestock. If as I suspect only a
few % of all beef cattle feed is produced from arid land, it seems silly
to seek justification THERE for the use of ressources for beef production.

Given the world oversupply of arable crops I don't think any
justification is needed anyway. In fact we could do with even more.

--
Oz
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Michael Percy writes
Oz wrote:

I would define arid as being where the transpiration rate exceeds the
precipitation by four inches for three months of the year.

That definition can't be useful. It says nothing about three
quarters of the year.

Eh?

Ahh, perhaps not clearly put.
I meant the total precipitation resulted in three month periods with a
constant *soil* deficit exceeding four inches.

An
alternative might be something along the lines of never achieving field
capacity in the top 150mm for two years.

Puts severe bounds on the amount of rain in short term rain events within
those two years. Conversely sevents might trigger a change in status from
arid to semi-arid, even when events are insufficient to allow rainfed
agriculture.

It does rain in arid areas, I know. I stood in the moroccan desert last
year with no visible green (for 100's of km outside oases) being wetted
by modest rainfall.

2" of rain in a desert does not mean you can now call it 'semi-arid'.

By my definition Tinbouctou would be arid. What would it be
according to your definition -- to be precise, in how many years out of 10
would it be arid?

Perhaps you can give the last 10 year's rainfall, although as I
understand it tinbouctou is an oasis.

Remember there are places in the UK with sub 20" average rainfall, and
you would not describe them as remotely arid.

You caught me emptyhanded there. I had left the definition of remotely arid
undecided thinking I'd never need it.

How would you classify 20" rainfall then?

--
Oz
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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

Michael Percy writes

I was talking about land with less than 10 inches of rain avg, in your
setting that would start well south of Catherine.

What I am trying to point out to you is that the rainfall per se is not
the only, nor often, the most important aspect of aridity.

IT depends on the transpiration rates and the periods where growth stops
due to lack of moisture.

In the UK, for example, were I blessed with 10" rainfall evenly spread
through the year to roughly match transpiration I would be growing
massive crops with nary a worry in the world.

Equally someone with 30" of rain in low latitudes and high daytime
insolation and temperatures and with much of it coming erratically in a
few summer cloudbursts is going to be very arid indeed.

--
Oz
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Michael Percy writes

Sub-humid.

What crops at what yield levels would you expect at this rainfall?

What ruminant production (if any).

--
Oz
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Michael Percy writes
Oz wrote:

Michael Percy writes

Sub-humid.

What crops at what yield levels would you expect at this rainfall?

What ruminant production (if any).


Oh, the usual stuff. Llamas and pot :-) Come on,
you told me it was somewhere in central/east England.

Not much of an answer, is it?

Can't you do better?

--
Oz
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Michael Percy writes

Do a reality check with a rainfall map of earth. What you see, the rainfall
isosomethings in the range 0 to 20" closely capture the arid parts of earth
including the deserts. Don't ask me why it does, but it is a fact. You
can't get the same mileage from a transpiration rate map.

That's a rather huge range, to put it mildly, and puts parts of the UK
and europe under your designation of 'desert'. Equally parts of the
world I would describe as 'arid' do indeed have significantly more than
20" rainfall, particularly at low latitude with seasonal intense
rainfall.

In the UK, for example, were I blessed with 10" rainfall evenly spread
through the year to roughly match transpiration I would be growing
massive crops with nary a worry in the world.

Could be quite a tourist attraction too

Not much of a reply, can't you do better?

Equally someone with 30" of rain in low latitudes and high daytime
insolation and temperatures and with much of it coming erratically in a
few summer cloudbursts is going to be very arid indeed.

Equally someone with 90" of rain all of it coming in a single annual
cloudburst the rest of the year being dry and 40 centigrade. Remember
earth has certain design limits. Some conditions are rare if ever.

90" is not likely. Certainly 20" or more in a few rain sessions is not
so uncommon, particularly in continental areas at low latitudes. Runoff
is indeed typically severe but (being continental) they cover large
areas. Great tracts of asia (mongolia and around the himalaya) are
almost entirely pastoral.

The restriction of cropping isn't confined to low rainfall areas either.
Many areas that have shallow soils but high rainfall cannot be cropped.
Take a look at the west of england, particularly wales northward, and
you will find the vast majority of the farmed area cannot be cropped but
is good stock country. It's rather tricky cropping when you have a 90"
rainfall.

--
Oz
This post is worth absolutely nothing and is probably fallacious.
Note: soon (maybe already) only posts via despammed.com will be accepted.

Oz wrote in message
...
Michael Percy writes
The restriction of cropping isn't confined to low rainfall areas
either.
Many areas that have shallow soils but high rainfall cannot be
cropped.
Take a look at the west of england, particularly wales northward, and
you will find the vast majority of the farmed area cannot be cropped
but
is good stock country. It's rather tricky cropping when you have a 90"
rainfall.


don't even need to by as high as 90 inches, add in the right (or wrong)
soil type and you have problems with cropping at 48", unless it falls at
just the right time. Over here on the west side of the UK a lot of land
has too much water for arable cropping.


--
Jim Webster

"The pasture of stupidity is unwholesome to mankind"

'Abd-ar-Rahman b. Muhammad b. Khaldun al-Hadrami'


--
Oz
This post is worth absolutely nothing and is probably fallacious.
Note: soon (maybe already) only posts via despammed.com will be
accepted.

Michael Percy wrote in message
...
Oz wrote:

Michael Percy writes
Oz wrote:

Michael Percy writes

Sub-humid.

What crops at what yield levels would you expect at this rainfall?

What ruminant production (if any).


Oh, the usual stuff. Llamas and pot :-) Come on,
you told me it was somewhere in central/east England.

Not much of an answer, is it?
Can't you do better?

I can be less kind.

but hardly contribute less to the discussion


--
Jim Webster

"The pasture of stupidity is unwholesome to mankind"

'Abd-ar-Rahman b. Muhammad b. Khaldun al-Hadrami'

In article ,
"Jim Webster" wrote:

Oz wrote in message
...
Michael Percy writes
The restriction of cropping isn't confined to low rainfall areas
either.
Many areas that have shallow soils but high rainfall cannot be
cropped.
Take a look at the west of england, particularly wales northward, and
you will find the vast majority of the farmed area cannot be cropped
but
is good stock country. It's rather tricky cropping when you have a 90"
rainfall.

don't even need to by as high as 90 inches, add in the right (or wrong)
soil type and you have problems with cropping at 48", unless it falls at
just the right time. Over here on the west side of the UK a lot of land
has too much water for arable cropping.

Depends what you're trying to crop. Most of the north Queensland
sugarcane crop is grown at 80 to 120 inch rainfall -- and a fair bit
of the land is cleared _Melaleuca_ swamp. (Admittedly not a *good*
choice, but it seems it has been profitable at times.


Cheers, Phred.

--
LID

Phred wrote in message
...
don't even need to by as high as 90 inches, add in the right (or
wrong)
soil type and you have problems with cropping at 48", unless it falls
at
just the right time. Over here on the west side of the UK a lot of
land
has too much water for arable cropping.

Depends what you're trying to crop. Most of the north Queensland
sugarcane crop is grown at 80 to 120 inch rainfall -- and a fair bit
of the land is cleared _Melaleuca_ swamp. (Admittedly not a *good*
choice, but it seems it has been profitable at times.

that's where soil type and temperature comes in and shows why just
picking rainfall as a guide is a waste of time. We are at the limit of
Maize growing so our chances of growing sugar cane are slightly less
than my wifes chance of becoming next pope.
Also a lot of the land has rock a tad to close to the surface for
ploughing and a shade steep for comfort.
We could plough more than we do. During the war, "WAR-AG" got a lot more
land put under the plough, although the damage they did then to old
stone drains and underlying soil structure is just beginning to come
right again.
At one point in the 19th cent about a third of the land on this farm
went into cereals, mainly oats. The coming of the railway meant it was
possible to get milk into the cities and the dairy industry developed.


--
Jim Webster

"The pasture of stupidity is unwholesome to mankind"

'Abd-ar-Rahman b. Muhammad b. Khaldun al-Hadrami'



Cheers, Phred.

--
LID