Re:Use of nitrate

>From: stevensj at calshp_cals.wisc.edu
>Date: Fri, 30 Jun 95 18:47:42 CDT
>Subject: Do plants use nitrate?
>Hi Everyone,
>I've just had a discussion with my local store owner after reading a post
>from George Booth saying how Echinodorus may like high-ish nitrates (10-20
>ppm).  My store owner says plants don't use nitrates, they use ammonia -
>is he correct?
>I was thinking Geroge was right, particularly since my swordplants have
>never done particularly well (look OK, just haven't grown nearly as big
>as their parents).  Mine were in a 125 gal tank with UGF and nitrates
>0-4 ppm.  I have now moved them to tanks without UGF & higher nitrates.
>Their parents are in a 110 tank with laterite & UG heating (owned by the
>store owner).
>Also ... I was wondering if anubias might need nitrates also.  My anubias
>did poorly when I reduced nitrates in their 25 gal tank, but this kind of
>coincided with anaerobic substrate & they just disintegrated :-(.
>Any comments would be appreciated.  Hopefully I'll be in the fishroom
>tomorrow & maybe we can discuss this there.

Hi Joanne.  Aquatic plants do very well on nitrates.  I once grew 8 genera,
including Vallisneria, Elodea, Ceratophyllum, and even Aponogeton
madagascareinsis, in sterile culture,(well, almost sterile, at least
algae-free), in flasks with nitrate as their only source of nitrogen.  They
all grew very rapidly and used up all the nitrate supplied.  This is not to
say that they can't also use ammonia.  I believe that if you have
measurable nitrate, even as low as 1PPM, that should be plenty for your
plants.  If the plants aren't doing well, look to other needs, nutrient, or
otherwise.  With UGF, iron deficiency is likely to occur.  I grow my plants
in soil or a soil-gravel mix, with no filtration of any kind.  I am sure
that Anubias can use nitrates also.  Anubius is one type of aquatic plant
whose roots do not appear to be adapted for living in anaerobic mud.  I
have noticed that Anubias does almost as well floating as rooted, and that
Anubias roots tend to attach to stones and gravel the same way that the
modified roots of ivy cling to stone.  For Anubias, I would put just a
small amount of soil (like 1/4 inch) at the bottom, and then have about 1.5
inches of gravel.

Paul Krombholz