On Sat, 4 May 2002 10:37:32 +0900, Tom Bridgeland <[log in to unmask]>
wrote:


>> Would you expect that the grassland (it would be wood in most cases)
>> has a productivity equal to or similar to a corn field?
>
>Yes, actually, the productivity of temperate grasslands is second only
>to tropical rainforests. Corn is not magic. It is a grass, growing
>under the same sun and with the same nutrients and rainfall. Total
>biomass productivity isn't much different.

Well I used the data from a agricultural handbook.
( wrote about this in
http://maelstrom.stjohns.edu/CGI/wa.exe?A2=ind0204&L=paleofood&P=R2599 )

The data displays, that good managed grasslands have about the same
bioproductivity as c field of corn, for example.
But the growth requires not only rainfall and sunlight, but also enough of
soil nutrients. Particularly nitrogen.
This requires intense fertilisation. Under this circumstances grasslands
produce as much as any other crop.
If not fertilized the bioproduction is only 10 or 20%, as the example of
"rare grassland" and ordinary meadow displays.

If you take the original bison living area in America, I'd expect that after
a couple of years the nutrients in the upper meter of soil will be exhausted
and go back to the smaller numbers.

I haven't seen numbers on the bioproductivity of tropical rainforests.
But I know that the nutrient availability there is very small, because
nearly all of the nitrogen is already in the biomass.
When farmers burn down the rainforest they experience very good harvests for
some years, but the soil nutrients are exhausted quickly and they move on to
burn down the next piece of rainwood.

>In prior times it would
>have been considerd crazy to waste grain on cows, it is only with
>grain subsidies that prices fell to the point where it made "sense" to
>mass grain feed animals.

Even here in Europe much maize is grown for the sole purpose to feed
animals. I think the reason is that it is easy to keep the fedder in form of
silage. And that maize accepts enormous amounts of nitrogen fertilizer -
transforming it to plant protein.

More ancient grains like spelt do not respond to fertilizer at all.
They are adapted to a more natural supply of soil nutrients.

>A managed range bison herd would have the same life cycle as a managed
>range cow herd.

Yes, I would expect that. The same is for deers which are kept and fed "in
prison". But this deer or bison wouldn't be wild game anymore.
If they grow so quickly, than their fat displays their growth rate.
Few EFAs. Much SFAs and MUFAs, which are the the first stage what animals
make out of too much carbohydrate intake.
Just the same what humans make of surplus carbs.

Healthy animals to eat just need enormous amounts of space to live on.
No problem for small populations.

regards

Amadeus