Re: your mail

[roger haar <haar@soliton.physics.arizona.edu>]

Hi

	Burning grass tends to reduce "weeds" like many trees and brush and
woody perenials.  In many third world countries, the straw from wheat is 
burned rather than tilled into the soil to build up the soils organic 
content.   The probable reason for this is staw is mostly carbon and to decay
requires nitrogen which is frequently the limiting nutrient in these 
countries.  Burning does return most of the other nutrients to the soil 
quickly conpared to decay.  Short term burning gives better crop yield, 
but there are serious questions about long term effects on the soil
since the organic content drops and thus the holding capacity for water, 
and many minerals also drops.

	In grasslands, burning often simulates the grass.  Fire is a 
natural part of the grassland's lifecycle.  But overburning is not natural.
The soil in grasslands is mostly enriched in organic content by the grass 
roots rather than the upper parts. Fires seldom kill the roots.



Thanks roger
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On Fri, 6 Sep 1996 drdock00@ukcc.uky.edu wrote:

>      It's hard for me to see how this is a problem.  Grass is short lived and
> replentishes itself quickly so aside from speeding up the recycling process
> I can't see that burning grass does much of anything.  Anybody know why they
> burn the grass so often?  Does it have something to do with weed control?