"Martin Brown" wrote in message
...
Charlie Pridham wrote:

"nambucca" wrote in message
...

"H Ryder" wrote in message
...


I always spread mine green and am far from convinced that much nitrogen
is
robbed from the soil as its on the surface surrounded by air which is
around
70% nitrogen. And it is a lot less work! It may well be different if
buried.
but it does make lovely compost if you have the energy :~)

Air is 75% Nitrogen, but in an inert form that plants cannot use. It
take symbiotic bacteria in legumes and clovers to fix nitrogen into
soluble nitrate form. Or the industrial Haber process...

Your soil may tolerate this sor tof mulch but fertility will suffer.

Regards,
Martin Brown

I quite agree plants can not use the nitrogen direct, but we are not talking
about plants but about the bacteria that break down the shreddings and since
they will "compost" the shreddings in an open bag on concrete with no
contact with the soil they Must be able to get all the nitrogen they need
from the air, I have done soil samples before during and after surface
mulching with green material and soil fertility increases not decreases
during the process. In short the books are wrong on this one.
--
Charlie, gardening in Cornwall.
http://www.roselandhouse.co.uk
Holders of National Plant Collection of Clematis viticella (cvs)