[Bioconversion] Re: [Gasification] instead of ethanol -- make natural gas??

[AJH]

On Mon, 14 Nov 2005 19:41:08 -0500 (EST), Jeff Davis wrote:

>
>I see your point, and it is a good one! I would think that your gasifier
>filter would trap most of the ash and that would be returned to the field.
>What are your thoughts on that?????????

As I said "nutrient" chemicals will be lost from both flue and ash.
The flue gases may wash out of the atmosphere quite quickly, I don't
know but there may be some soils that this cropping causes problems
with. Think of the dustbowl of the midwest which seemed to result from
immigrant  European farmers not realising the soil differed from their
home lands and requiring different treatment. Similarly we are told
the Sahara moved north as grain growing depleted the fertility and
lost the ability to maintain a plant cover. I think you have to look
on topsoil as something plants have concentrated their needed
chemicals in over millennia, they have evolved to lock and retain
these chemicals that have been won from underlying sub strata. When
man comes along and takes a crop he not only removes some of these
chemicals in the ash but also exposes what remains to weathering and
loss by leaching before plants can take them up again. This is why
thought is needed on when to return ash as a fertiliser.

My initial point was that woody plants have lower removals of
chemicals than the grasses and shorter rotation  materials and in UK
on nutrient rich clay soils we have a culture of repeated rotational
cropping with no major shortage of nutrients ( this is really the
wrong term and nutrients in human diet contain energy so I should
restrict myself to the term fertiliser but old habits die hard). Other
climates are not so benign and the chances are those soils which have
become depleted and abandoned suffered the same practises less well.


AJH