David Hare-Scott wrote:
Farm1 wrote:
songbird wrote:
David Hare-Scott wrote:
Farm1 wrote:
David Hare-Scott wrote:
After two years of La Nina and plenty of rain we haven't had
significant rain in three months. But clever people still want to
burn their pasture

????? Is that how it started or was it a farm burnoff? The only
people who I've heard of seen who still burn stubble are the odd
wheat farmers out west.


I am in a beef cattle area where there are many landholders who
still do things the way that Grandpa did. Every Spring just before
the expiry of the
burn-without-permit season they burn their paddocks. They
overstock and use
set stocking in big paddocks and don't mind if their bulls cover
their own
offspring. It's a time warp.

if the genes are weak then the inbreeding will make
it obvious.

i don't understand the burning thing though, as it
puts nutrients into the air instead of into the cow.

Actually burning is quite beneficial to the soil because it adds (if I
recall correctly) phoshorus to the soil (although it may be another,
or even a number of other nutrients). Australian Aboriginals and
many other native peoples did it as a 'farming' technique as after
the burning, grass grew strongly and brought in grazing animals that
they then killed for food. It's not a good technique though in fire
prone areas and quite antisocial these days because of pollution.

Burning only adds phosphorus to the soil if it is present in what you burn.
This is the basis of slash and burn agriculture where the nutrients in trees
are released allowing a crop to grow in the ashes. In Oz which tends to
have phosphorus impoverished soil the P is held mainly in the trees, burning
the forest releases this. So our white forebears used fire to clear forest
and increase fertility at the same time but then found that the great crops
they got in the first year or two couldn't be sustained. S&B only works if
you have plenty of forest to move on to when the current patch becomes
exhausted, which was fine for the aboriginals who lived at a low population
density and were ready to move as required.

Burning pasture doesn't achieve anything like that, you are much better
slashing with a mulcher which retains nutrients and carbon in the soil. The
perpetrators are seduced by the apparent reduction of weeds and the nice
flush of new growth you can get if there is rain afterwards but in the long
run it's a loser as volatile nitrogen compounds are lost and so is soil
carbon. But as one neighbour put it "its fun".

*grr!*

right, slash and burn agriculture is a completely
different thing than pasturage as also would be the
burning of wild areas for encouraging native
species and those who must have fire for completing
their life cycle.

the point of "adding" anything to the soil by
burning is more like the changing the accessibility
of the nutrient, but like you say that only works
if there is rain shortly afterwards. the greater
the gap between burn and rain the more likely
there is a breeze to take the ashes away. a heavy
rain means runoff which puts a lot of those freed
up nutrients into the streams. there really isn't
a whole lot of good about slash and burn compared to
other things that can be done. even taking the
brush and burying it will at least keep the carbon
and nutrients nearer the place where they were
formed instead of exporting them into the air or
into the streams.

but to get to pasturage, burning during a drought
exposes more of the soil surface to drying winds
and the heat of the sun. plus removing any of the
dry stalks that can soak up some of the extra
water if a heavy rain comes along, protecting the
soil from the rain drop impacts (reducing compaction),
erosion protection... it's just so completely
and boneheadedly wrong.


songbird