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Re: Aquatic Plants Digest V2 #952
Dave Whittaker wrote, Sept 13:
>Subject: Re: Soil substrates
>
>Here is a question for Dave Huebert or Paul Krombholz
>if either of you care to answer it. I know that you two
>prefer soil mixtures.
>
>Why is a silty soil or loam of low organic content
>preferable to one of high organic content and how
>inhibiting is a good topsoil? As a general rule do
>you cut your soil with course sand or gravel?
>
>My rooted plants are doing alright in a sandy topsoil;
>however, all of the stem plants remain frozen in time
>without PMDD. This is especially true when there is
>no CO2 addition. When I use a "natural approach" as
>advocated by Dave, my stem plants don't grow. By far
>the best growth these plants have shown to date is in
>a tank with a course gravel substrate, PMDD, CO2, and
>no substrate additives save fish poop.
>
>Of course the anubias grow best in fresh air. Has anyone
>successfully cultivated Anubias lanceolata submersed?
>
I'll take a stab at it. It depends on the plant whether or not a low
organic content is desirable or not. My crypts really like high organic
content soil, either 50:50 soil-peat or 50:50 soil cow manure (composted
for two weeks before use). Swords seem to like high organic matter soil,
also. With regards to most other plants, I don't really know if high OM
soil is better than low OM soil. I have seen evidence that most of the
Aponogetons prefer low OM soil. Large brown dead areas or holes form on
the older Aponogeton leaves when they are in high OM soil. Lace plants
like low OM soil, and they appear to also need the roots of other plants
present or they will develop the large brown dead areas even in the low OM
soil.
The size of the air channels in the roots may be a good indicator of how
much organic matter the plants can tolerate. If the roots are fat-looking,
white, and rise to the surface rapidly, then the plant is probably adapted
to high OM soils. Crypts certainly have roots like that, and so do many of
the swords and also, Sagitteria, by the way. On the other hand,Anubias
barteri var. nana roots only rise to the top slowly, and if I mash one
underwater, only a small amount of air comes out, compared with a root from
most other aquatic plants. These aspects of nana roots, along with the
fact that they attach to pebbles or even glass like ivy rootlets, indicates
that they are unlikely to be adapted for an anaerobic substrate. So, I
grow nana in coarse gravel with just a trace of low OM soil at the bottom
of the dish.
Some plants, such as Vallisneria, Elodea densa and Najas seem to be rather
indifferent as to the amount of organic matter in the soil. There are a
lot of other plants where I just don't know whether they would do better in
low or in high OM soil. It would be easy to do experiments if I had the
time and a few more tanks. All one would need is two containers in the
same tank, one with low OM soil and one with high OM soil. Have the same
plant species in both and see which does best. Then, of course, tell us
about it. One thing I have seen with crypts is that they are more
resistant to meltdown when in high OM soil, and, they look sturdier and
darker. I have had some Echinodorus uruguayensis (red horemanii) that
started out fine in low OM soil, but, after about 6-9 months, began to show
signs of iron deficiency that was cured by adding chelated iron. to the
water.
I usually have the soil underneath about an inch of gravel, and I do not
make any effort to mix the soil with the gravel. To get low OM soil I go
into the woods and collect some of the top soil, mix water with it until it
is 'soupy', and then strain it through window screening or a rice strainer.
This catches all the undecomposed leaves and roots and I pour this 'soil
soup' into the bottom of the aquarium and put in the gravel over that. For
high OM soil I get the same soil in the woods and mix peat or cow manure,
roughly half and half, and let it compost in a shoe box or sweater box for
a few weeks before placing about an inch on the bottom and then covering
with at least a half inch of gravel.
When you say your rooted plants are doing alright but not your stem plants,
I assume that you mean that the crown-type plants are doing all right, but
not the stem-type plants, which should also be rooted. If your stem plants
are not rooted, then that may be the problem. If they are rooted but are
not growing, then probably they need one or more mineral nutrients or more
CO2. You did indicate that PMDD helped and also CO2. I don't think you
can count on the soil to be a long-term source of most mineral nutrients
except iron and perhaps some of the other micronutrients. The volume of
the soil in a tank or a pot is not very much compared to what a plant has
access to in nature. The inability of soil to serve as a long term source
of nutrients is not a big problem, because aquatic plants in my experience
all respond quickly to even small additions of nutrients to the water.
According to Kasselmann, Anubias lanciolata is a synonym for A. barteri
var. glabra or var. angustifolia. Both of these, according to her, can be
successfully grown underwater, although they grow very slowly. I have not
had this variety, but my experience with var. nana and var. barteri and
with A. aufzelii, indicates that CO2 additions greatly increase the growth
rate.
-----------------------------
>Subject: Re: Red Ramshorn Snails
>
Merrill wrote Sept. 13:
>...There is a brilliant Red Ramshorn Snail available somewhere in the World
>which is a good algae eater. It was imported into the United States
>through the Netherlands some years ago. Southern Tropicals in Florida
>exhibited these gorgeous Ramshorns at the Fish Farmers' Show in Florida,
>but evidentially lost the snails somehow sometime after the show. I was
>told that they came from someone in Italy that was producing them when I
>inquired in the Netherlands.
>
>If there is someone from Italy reading this, do you know about the
>availability of these gorgeous, brilliant blood-red snails? They are a
>lovely addition to the planted aquarium.
>
I have two color varieties of ramshorn, brown and red, although my red
variety may not be as brilliant red as the one you describe. I wonder if
these color varieties are controlled by a single pair of genes, as in the
case of blond and brown guppies.
Subject: snails and disease
>
Martyn Mitchell wrote, Sept 13:
>
>I've been reading submissions about snails with great interest. I've
>been avoiding snails in my tank as I know nothing of their potential for
>being vectors for diseases and /or parasites of plants and fish alike.
>
>
The chances of snails obtained in the aquarium trade being infected with
trematode parasites (flukes) is almost nil, and even if they were, the only
dangerous one would be one of the blood flukes, where the snails could shed
cercaria forms that could penetrate human skin and get established as
adults. All the other flukes encyst somewhere after leaving the snail and
have to be eaten. If you must eat your fish and plants, be sure to cook
them, and everything will be fine. Snails get infected with human
trematode parasites that hatch from eggs in human feces or urine. Snails
from ditches in places where bilharzia (also called schistosomiasis) is
endemic, could be a problem, but there are rather strict quarantine laws
regarding the importation of any material containing blood flukes. I heard
the story---don't know if it is true---that Asa Chandler and Clark Read,
parasitologists who wanted to study blood flukes in America could not get
permission to import them and so they (or one of them) smuggled the flukes
in by getting himself infected abroad and collecting eggs when he got back.
The two wrote a marvelous parasitology textbook wherein they mention their
personal experiences with most of their subjects.
Paul Krombholz in Jackson, Mississippi, where the early fall weather has
been delightful.