Aquaponics Digest - Sun 02/21/99
Message 1: Re: good bacteria
from doelle
Message 2: Re: advise ... try Semco
from "KevinLReed"
Message 3: Re: tamarisk ,and out there....
from jilli and lars
Message 4: Re: good bacteria
from jilli and lars
Message 5: Re: good bacteria
from jilli and lars
Message 6: Re: Solar Heat
from jilli and lars
Message 7: Re: Lettuce post-harvest handling
from Adriana Gutierrez
Message 8: Re: Solar Heat
from "Jorg D. Ostrowski"
Message 9: Re: good bacteria
from "Jorg D. Ostrowski"
Message 10: RE: Lettuce post-harvest handling
from "Anthony & Roberta"
Message 11: Re: tamarisk ,and out there....
from William Evans
Message 12: RE: duckweed
from Jose Pelleya
Message 13: PACU
from Jose Pelleya
Message 14: missing URL
from Jose Pelleya
Message 15: Re: missing URL
from Glen Seibert
Message 16: Re: good bacteria
from "Marc S. Nameth"
Message 17: Re: request for nutrient supplier
from Jaarvis
Message 18: Re: good bacteria
from Michael Strates
Message 19: Lettuce Harvesting Idea
from Michael Strates
Message 20: Re: good bacteria
from Michael Strates
Message 21: Re: good bacteria
from uweb@megalink.net.mx
Message 22: Re: good bacteria
from doelle
Message 23: Re: good bacteria
from doelle
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 1 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: doelle
Date: Sun, 21 Feb 1999 18:22:20 +1100
A>I apologise. You want some kind of bacteria that can turn H2S back into
>sulphur compounds, rather than venting away precious sulphur. Hydrogen
>sulphide can be scrubbed easily with iron sponge.
>
You can do whatevr is the most convenient as long as you do not vent giving
people a headache and nausea.
Horst
>
Horst W.Doelle, D.Sc., D.Sc. [h.c.]
Chairman, IOBB
Director, MIRCEN-Biotechnology
FAX: +617-38783230
Email: doelle@ozemail.com.au
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 2 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: advise ... try Semco
From: "KevinLReed"
Date: Sun, 21 Feb 1999 00:00:40 -0800
Hello Glennert,
Try Semco trowelable waterproof membrane material. They will have it, or
something comparable at most ceramic tile or building supply store. It is
normally used to water seal cement shower pans or outdoor fountains or made
of porous materials. It is very easy to use but be careful to calculate the
area to be covered carefully as it can be expensive if you buy more than you
need. Two very thin coats seems to work quite well.
It works well as an adhesive to it you want a decorative edge on your cement
pond.
Kevin
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 3 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: tamarisk ,and out there....
From: jilli and lars
Date: Sun, 21 Feb 1999 02:53:26 -0800
Hello william (bill?) -
I'm very sorry i didn't remember you're name.
The various sites i found concerning this plant mostly seemed to
suggest that it concentrated sodium around its roots. I didn't realize that
this was from it's own leaf mulch.
This ommitance kinda makes sense, as most of the sites were devoted
to tamarisk as a pest, rather than tamarisk as a cultivated species.
Thank you very much for clearing this up. I also won't feel too
guilty when i dig some up the next time i'm wandering around and find
myself a grove, as most efforts are geared towards its eradication anyway.
Though i am a bit concerned about the water loss...........
lars fields
William Evans wrote:
> Sodium salts are taken up by the foliage in a big way as well..the
> accumulated "litter" in the grove (there never is just 1))) eventually
> salts up the surface soil enough,,dont forget sucking the swamp dry,,,,
> so that the tamarisk makes MANY more while runnin out the competitio
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 4 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: jilli and lars
Date: Sun, 21 Feb 1999 03:14:01 -0800
hello greywater folks -
Why the concern with hydrogen sulfide?
I know the stuff smells kinda funky, but it's not dangerous is it?
And why the concern for venting
'precious sulphur"? Isn't sulphur generally abundant?
I would think that a little bit of anaerobic activity in a greywater
system would be advantageous,
mainly as it means that you've managed to maintain a different
chemical/biological system within a larger
chemical/biological system, which means a _chemical gradient_, which will
expose your wastes to as much
biological activity as possible.
The more biological activity means the more processes your molecules
are going through, which means
the more likely they are transformed from something manufactured by humans
into something that has been
biodegraded into harmlessness or usefullness by macro-organisms.
Just a wild guess, really...
lars fields
----------------------
doelle wrote:
> A>I apologise. You want some kind of bacteria that can turn H2S back into
> >sulphur compounds, rather than venting away precious sulphur. Hydrogen
> >sulphide can be scrubbed easily with iron sponge.
> >
>
> You can do whatevr is the most convenient as long as you do not vent
giving people a headache and nausea.
> Horst
> >
>
> Horst W.Doelle, D.Sc., D.Sc. [h.c.]
> Chairman, IOBB
> Director, MIRCEN-Biotechnology
> FAX: +617-38783230
> Email: doelle@ozemail.com.au
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 5 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: jilli and lars
Date: Sun, 21 Feb 1999 03:50:12 -0800
Hi all -
Almost wherever i go, i try to carry plastic containers or bags or
something that will hold small amounts of liquid. If i come across a pond, or
even a puddle that appears to have biological activity, i take a sample. This
sample will likely contain some kind of bacteria. The stranger the environment,
the better.
Are you familiar with Lynn Margulis?
Basically, bacteria are rather unique among life-forms in that they do
not need to reproduce in order to alter their genetic makeup. Bacteria have
various methods for transferring genetic material across individuals and _even
_across_species. What that means is that, potentially, all bacteria share and
can 'pull from' one giant, global, bacterial gene pool. For example, a
population of bacteria need not evolve in order to gain resistance for a
particular antibiotic , they can potentially be 'infected' with the gene which
carries the resistance for that particular biocide.
As an analogy, the world bacterial gene pool is quite like this internet
I am now communicating with (though it is _billions_ of years older). Bacterial
genes, analogous to new ideas or cultural practices, can spread from individual
to individual quite rapidly. In other words, for bacteria, genes are potentially
as easy to modify as we can change our minds. It all depends on exposure....
And we only just figured this stuff out. They've been doing it for
billions of years. "Information wants to be free"...
By taking samples from various ponds and other bacterial sources, you
are exposing your isolated bacteria to the greater world of bacterial genetic
information. You are exposing them to new (an potentially dangerous, i suppose)
'ideas'. You are allowing them to take part in the greater bacterial genetic
dialogue. If you don't continually 'innoculate' your isolated system with fresh
bacterial sources, you could be isolating your bacteria into an incestuous,
stagnant, dead end.
lars fields
------------------------------------------------
Jorg D. Ostrowski wrote:
> Gentle: I am now trying some beneficial micro-organism from FENIC Co.,
> effective micro-oganism from EM Technologies, and Microbe-Lift from
> Ecological Laboratories. I am having some successes, some unexplained
> failures. I am even trying compost tea, which has some promise. I need
> some natural biological microbes or aerobes that can multiple once
> inocculated into any of the 3 indoor greywater storage tanks. I need to
> keep it SIMPLE. I want to avoid moving parts, mechanical devices and
> energy consumption.
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 6 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: Solar Heat
From: jilli and lars
Date: Sun, 21 Feb 1999 03:52:01 -0800
hey jorg -
where have you found these collectors?
What sort of place should i be looking?
thanks,
lars
Jorg D. Ostrowski wrote:
> You said:"thats an amazing price - where, exactly, is your 'local' supply
> house?"
> _________________________________________________________________________
> Lars & Marc: We have bought many solar hot air and hot water collectors
> for $25 each and put them onto real world projects. Jorg Ostrowski
> _______________________________________________________________________
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 7 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: Lettuce post-harvest handling
From: Adriana Gutierrez
Date: Sun, 21 Feb 1999 07:59:14 -0500
Roberta,
Do you have a name or supplier for this machine? How about cost?
Adriana
> last machine could possibly be adapted on a track for table top harvesting.
> Or the track can run above the raft system . The mini disc cutter can run
> off a small motor and the vacuum can distribute it to a harvesting box. I
> believe the first 2 machines are patented.
>
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 8 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: Solar Heat
From: "Jorg D. Ostrowski"
Date: Sun, 21 Feb 1999 06:36:36 -0700 (MST)
Lars: We got ours through auctions and Bargain Finder. Jorg Ostrowski
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 9 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: "Jorg D. Ostrowski"
Date: Sun, 21 Feb 1999 06:57:33 -0700 (MST)
You said:"Why the concern with hydrogen sulfide? I know the stuff smells
kinda funky, but it's not dangerous is it? And why the concern for venting"
___________________________________________________________________________
Lars: H2S is definitely poisonous! One of the main criteria for our
demonstration home/office is occupant health and environmental
stewardship. We are not using city water lines, sewer lines and have no
gas line, furnace or boiler. We also have had 30,000 visitors. Not only
has H2S to be vented, but also prevented in the first place, if possible.
This is why I am searching for the good bacteria, aerobes, micro-organisms,
microbes, or enzymes or whatever can do the job, by inocculating the
storage containers. As has been pointed out by others and by experience
marine life can NOT generally take H2S dissolved greywater very well. The
crayfish seem to be OK, paradise fish seem to be uncomfortable and white
cloud minnows die (they are very sensitive). When percolated slowly through
the system, everything is fine and the water hyacynth and hydroponics
can handle the load, but on high volumes the fish die. Due to the
effect on humans and fish, I must find an amiable, natural, simple,
biological and cost-effective solution. I hope that the introduction
of compost tea (from the waterless toilet or vermicomposting system)
can introduce the right bacteria, aerobes, micro-organisms, microbes, or
enzymes or whatever can do the job, by inocculating the storage containers.
Please forward this note to anyone that may have some leads or products
that I should try.Thanks for assisting in this quest.
*****************************************************************************
Jorg-Dietram Ostrowski, M. Arch. A.S. (MIT), B. Arch. (Toronto), Ecotect
- in full-time professional practice since 1976 (Straw Bale since 1978),
environmental/architectural design, ecological planning, consulting
on sustainable buildings/communities. Lectures, seminars, workshops.
- 3 residential demonstration projects in Canada, +80,000 visitors
- college campus and office tower recofit under construction
- living a conserver lifestyle & working in a sustainable home and office
ACE, ARE, ACT, ASH-Incs., Phone: (403) 239-1882, Fax: (403) 547-2671
Web Site [under construction]: http://www.ucalgary.ca/~jdo/ecotecture.htm
e-mail:
#########################################################
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 10 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: RE: Lettuce post-harvest handling
From: "Anthony & Roberta"
Date: Sun, 21 Feb 1999 10:33:58 -0500
We will look for it - the last machine is made for the ground you would have
to adapt yourself.
Roberta
eastgate@worldnet.att.net
Visit our web site at:
http://www.shaklee.com/link/eastgate_organics
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 11 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: tamarisk ,and out there....
From: William Evans
Date: Sun, 21 Feb 1999 08:20:13 -0800
yes it is a serious pest.It readily self seeds ground, result is a
blanket of seedlings....but if one wanted to pull sodium out of a sys,
it would do the job
bill
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 12 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: RE: duckweed
From: Jose Pelleya
Date: Sun, 21 Feb 1999 08:21:29 -070
Here's a file with it
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Second FAO Electronic Conference on Tropical Feeds
Livestock Feed Resources within Integrated Farming Systems
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Twenty seventh paper from B.X. Men.
Questions that might stimulate discussion on this topic
include:
1. Do you know other farming systems where ducks play a key
role (weeding, fertilization...) as in the Vietnamese
ricefields?
2. Are there economical figures demonstrating the benefit of
raising ducks in the ricefields?
3. Do you have figures on strategic supplementation of ducks
with local feed resources as aquatic plants for protein and
sugarcane or palm juice for energy?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE ROLE OF SCAVENGING DUCKS, DUCKWEED AND FISH IN INTEGRATED
FARMING SYSTEMS IN VIETNAM
Bui Xuan Men
Faculty of Agriculture, Cantho University, Vietnam
E-mail: c/o Dr Thu
thu%cantho2%cantho%sarec%ifs.plants@ox.ac.uk
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ABSTRACT
There are some 30 million ducks raised annually in Vietnam.
Most are scavengers raised seasonally in rice fields during
the early growth of the crop and immediately post-harvest; and
in backyards or gardens of farm households throughout the
year. Duck and fish production has been expanding and
contributes to increased income and improved living standards
of the farmers, especially for poor farmers in the remote
rural areas.
Trials on using duckweed cultivated as a partial or complete
replacement of protein supplement for feeding crossbred and
Muscovy ducks gave encouraging results. The practice of using
scavenging ducks to control insects and weeds in the rice
fields contributes to decreased investment and brings more
benefits for the farmers. Duckweed grown in the integrated
farming system is also a high quality feed for fish.
KEY WORDS: Ducks, local, scavenging, rice fields, duckweed,
fish
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
INTRODUCTION
The duck industry in Vietnam is of long standing and plays a
considerable role in providing meat and eggs in the diet of
the people (Men et al., 1991). Ducks are raised throughout the
country but are concentrated in the Mekong and Red River
Deltas, but also in suburban areas of the big cities.
Unlike the Northern countries, duck egg and meat consumption
is expanding in Vietnam and they provide important and
nutritious protein foods for people in both cities and rural
areas, especially the poor farmers in the remote regions. The
products are usually sold at a reasonable price that the poor
can afford and they can be processed into many different
traditional dishes and even special dishes in the restaurants
of the big cities.
The farmers use many traditional systems for raising ducks, of
which the rice-duck system is the most common. In this system
rice production is enhanced due to the ability of the ducks to
control insects and weeds and at the same time excrete manure
which provides nutrients for the growth of the rice plants.
There are also environmental benefits as chemical control of
insect pests and weeds is not needed. Along with the
improvement in rice, the farmers derive more profit from the
ducks because they forage themselves on natural feeds and
left-over rice in the fields which decreases the need for
supplementary feed. Ducks are also commonly allowed to
scavenge in the backyards or gardens of households in small
flocks, receiving household waste or rice to supplement what
they obtain by scavenging.
Today, ducks are also raised in partial confinement, either
for table eggs in coastal areas where shellfish gathered from
the sea are good mineral and protein sources for ducks, or in
areas where they are bred for meat during the dry season in an
integrated fish-duck system. Duck production makes good use of
available labour in rural areas and increases the income of
poor farmers, especially the landless. However, duck producers
have experienced problems since the introduction of high
yielding rice varieties because the time available for duck
flocks to scavenge is limited. Also, the price of feeds,
especially protein supplements, has greatly increased.
Consequently, although consumer demand for duck products is
increasing, the income for farmers is reduced by the high
input costs.
Duckweed (Lemna spp.), which is common throughout the country,
is a tiny water plant that grows very well on the surface of
stagnant ponds all the year round. It can tolerate high
nutrient stress and is able to survive extremely adverse
conditions, and appears to be more resistant to pests and
diseases than other aquatic plants in tropical areas. It has a
high content of nutrients in the DM, especially protein and
carotene, which are necessary for growing animals. Duckweed is
popular in Vietnam as a feed for fish and poultry, so it seems
a useful candidate for development as a year-round feed
resource for ducks and fish within the integrated farming
system.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SCAVENGING DUCKS
BREED
Several breeds of ducks are raised in the country. The two
different species are the common breed and the Muscovy duck.
The common breed is estimated at 80% of the duck population of
the country (Phuoc et al.,1993). They consist mostly of local
and improved breeds and a few exotic strains (Cherry Valley).
Of the local breeds, the first type is the "Tau" or "Co" breed
(grass ducks). This is a laying type that reaches mature body
weights of 1.3 - 1.5kg for females and 1.5 - 1.8kg for males.
Drakes can mate at 120 days of age. The females begin to lay
at 140 days old and achieve an average of 180 eggs per layer
per year with egg weights in excess of 60 g. This breed
tolerates hard conditions of nutrition and management, so they
are well suited to egg and meat production in the remote rural
areas. Also, they are very good at foraging for food such as
insects, water creatures and plants. The mating ratio of males
to females is 1:20-25, but this achieves highly fertile eggs
(over 90%) with high hatchability in traditional hatcheries in
the rural areas, even without electricity. The prices of table
eggs, ducklings and duck meat from these ducks are usually
lower than those of other types because of lower production
costs.
The second group, called "Ta" or "Bau" ducks, is a meat type
that achieves a mature live weight average of 2.5 kg. This
breed is low in reproductive ability and gives low profit to
the producers so the population has been decreasing.
The local Pekin has been imported for a long time and is
genetically poorly defined. It has degenerated into a dual
purpose breed. They achieve live weight gains and finishing
weights slightly higher than the "Tau" or "Co" ducks and the
number of eggs laid appears to be equivalent to the "Co"
breed.
There are several crossbred types which are a combination of
the local and exotic breeds. These are used for meat purposes.
The exotic Cherry Valley type has been imported from Europe
and gives high meat performance but, given the conditions in
which they are bred and raised, productivity and profitability
has declined and the population is decreasing. At present they
are raised for crossing and for meat around some cities. The
Khaki Campbell breed is a laying type imported from Asian
countries which achieves poor performance under the conditions
in Vietnam and the yield of eggs appears to be equivalent to
the local laying type (personal observation).
Muscovy ducks are estimated at some 20% of the population and
numbers have expanded throughout the country. These include
both local and exotic types, and their crosses. The local
breed achieves mature weights from 3-3.5kg for males and
1.8-2kg for females. The female lays on average 40-60 eggs per
year and hatches them herself under extensive conditions. The
Muscovies are suitable for smallholders with small flocks
because they are easy to manage and can consume different
feeds in the farming system. Also, the ducklings or table
ducks are usually sold at a higher price than common ducks.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SCAVENGING DUCKS IN THE INTEGRATED FARMING SYSTEM
DUCK RAISING ALONG WITH GROWING RICE
The ducks selected for this purpose are commonly the local
laying type or local Pekin breed due to their small body size.
They do not harm the plants, are active and forage well when
herded. In the brooding stage, after the first week of age,
the ducklings are driven into the rice fields from 20 days
after transplanting until the plants begin to flower. In the
young rice fields, the ducklings can catch destructive insects
such as white or brown hoppers, leaf insects, mosquito larvae,
spiders, small shellfish and fish. During scavenging, the
ducks consume weeds and stir and loosen mud around the rice
roots with their beaks without harming the rice plants. In
addition, they excrete manure to fertilize and stimulate the
growth of the rice. Insecticide and herbicide inputs are
rendered unnecessary, and labour for weeding is reduced. The
reduction in chemicals is beneficial to the environment.
The ducks are supplemented with feed consisting of by-products
of rice or rice grain, 3-4 times daily depending on feed
availability in the rice fields.
After the rice plants start flowering, the ducks are driven
from the rice fields to the canals, ditches, lakes and swamps
to forage in the water. The duck raising season usually lasts
for 3 months producing males for meat and females which
continue to lay eggs in the post-harvest rice fields. The
culled ducks are sold in the market.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DUCK RAISING IN THE POST-HARVEST RICE FIELDS
Along with laying ducks, the table ducks or ducks for meat are
reared in the rice fields post-harvest. Generally farmers
purchase ducklings from the hatcheries 3-4 weeks before the
rice harvest. The ducks usually selected are the native meat
type, local Pekin, crossbred local x Cherry Valley or Cherry
Valley.
After 3 weeks of age when the ducklings can consume whole rice
grains, they are permitted to enter the newly harvested rice
fields. They forage the whole day on leftover or fallen rice
grains, insects, shellfish, small frog and fish, and water
plants. In the late afternoon, they are moved to pens or sheds
on the dikes near the household until next morning. The ducks
raised at this time are usually finished at 2.5-3 months of
age, and achieve live weights of 1.6-2.0kg for the crossbred
Cherry Valley.
Now, most varieties of high yielding rice are planted and
harvested within a short period with only a limited time
available for the duck flocks to scavenge, so this traditional
system is becoming less feasible. In order to solve the
problem, a trial was recently carried out, feeding a
supplement of broken rice and crushed, dried fish (CDF) to
crossbred meat ducks (Cherry Valley hybrid x local Pekin)
herded in rice fields post-harvest, in order to shorten the
time to finish and improve the meat quality. Three supplements
of 50g/duck/day of a mixture of broken rice (80%) and CDF
(20%), 50g/day broken rice or 20g/day of CDF were given each
evening to the ducks, and compared with no supplementary feed.
The live weights at 70 days of age were 1855, 1749, 1659 and
1592g (P<0.001) and daily live weight gains 34, 30, 28 and
27g, respectively (Men et al.1995).
The results of the trial show that supplementation with broken
rice alone or a mixture of broken rice and crushed-dried fish
to scavenging crossbred meat ducks significantly improved the
daily gain and carcass quality, and would shorten the time to
market. This trial demonstrates a strategy for improvement of
the traditional method of the farmers in order to meet the
increasing demands of consumers for high quality duck meat,
and is consistent with today's rice cultivating conditions in
the country.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SCAVENGING DUCKS IN THE BACKYARD OR GARDEN
The system is common to most smallholders. Small flocks of
ducks from 5-50 head, producing eggs for the table or fertile
eggs for meat production or combining both, are allowed to run
loose in the backyards and gardens, and are fed household
wastes or rice 2-3 times per day and obtain other feeds from
scavenging in the ditches, canals, ponds or part of the rice
fields near the home. This system is very suitable for home
consumption of the products by the poor farmers.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DUCKWEED (Lemna minor)
Duckweed is a small floating aquatic plant that grows very
well on stagnant ponds and is commonly found throughout the
country. It has a high content of nutrients, particularly
protein and carotene, and tolerates adverse conditions such as
nutrient stress and attacks by pests and diseases. Duckweed
gives a high biomass yield as a result of rapid reproduction
and growth. When effectively managed, yields of 10 tonnes
DM/ha/year are possible (Preston, 1995).
Duckweed can be collected daily when grown on ponds manured
with effluent from biodigester systems and home waste, and
produce an average of 100g (38.6% CP of DM) fresh weight per
square metre (Men, 1995). Duckweed protein has a better
composition of essential amino acids than most vegetable
proteins and closely resembles animal protein (Culley, 1978).
Duckweed has long been used in poultry diets (Lautner, 1954).
Fresh duckweed (26.3% of DM) was used to replace soya beans at
levels from 19-27% in diets for fattening ducks at Cantho
University in Vietnam. There were no adverse effects on
health, but the reductions in growth rate and feed conversion
efficiency were considerable when duckweed replaced more than
20% of soybean protein (Becera et al.1994).
Recently, an experiment was carry out on crossbred ducks fed
roasted whole soya beans replaced by duckweed (38.6% CP in DM)
at levels of 0,30,45,60 and 100% in the diet (Men et al.,
1995). Daily gains of ducks fed duckweed were higher than
those of ducks fed a conventional diet because the duckweed ,
which was grown and managed well, had high nutrient
concentrations, especially of CP and carotene.
If duckweed is grown and collected by household farmers, the
feed cost could decrease 48%. However, feed conversion ratios
tended to be poorer on the diets with duckweed due to their
low energy compared to the control diet. In another
experiment, local Pekin were fed fresh duckweed ad libitum
(40% CP in DM) in limited broken rice diets at levels 80 and
60g/day compared to ad libitum feeding (Men et al., 1995).
Results obtained showed that the ducks with live weights of
1.5-1.6 kg can consume an average of 870g fresh duckweed per
day in the growing stage. The final weights and weight gains
of the ducks fed 80g broken rice were slightly lower than
those fed rice ad libitum, but the difference was not
significant.
Muscovy ducks are known to like duckweed very much. In 1994, a
trial was carried out on growing exotic female Muscovies at
Cantho University, where 15 and 30% of the dietary protein was
replaced by fresh duckweed from 28 to 70 days of age and
compared to a conventional diet (Men et al., 1994). At
finishing, daily gains were 37, 36 and 34g (P<0.001) and feed
conversion rates were 3, 3.3, 3.5, respectively.
Correspondingly, the cost of feed decreased by 15 and 26%
compared to the control diet.
In another trial, Men et al. (1995) fed local female Muscovies
on duckweed ad libitum with a limited amount of broken rice at
levels of 80 and 60g/day compared to ad libitum feeding from
28 to 70 day of age. Results achieved showed that local female
Muscovies consumed fresh duckweed less than the local Pekins
(325 vs 817g) and daily gains were 25, 20, 18g, respectively.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FISH IN THE INTEGRATED FARMING SYSTEM
Fish is a common food for Vietnamese people. Wild freshwater
fish are caught in many ways. At present, because of
indiscriminate exploitation, environmental damage caused by
overuse of agricultural chemicals and serious pollution caused
by humans, the precious food source is becoming impoverished.
In order to solve the problem, many farmers raise fish
profitably in ponds, even rice fields, in the integrated
farming system. The main feed sources for fish continues to be
based on natural aquatic creatures and plant feeds that grow
and develop themselves in the pondwater. In some regions,
farmers raise fish on feeds such as grass, weeds, leaves,
by-products from agricultural processing or animal manure and
obtained good results with fast growth of the fish. However,
the feeds only contribute about 20% of the requirements of the
fish (personal observation).
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DUCKWEED AS A FEED FOR FISH
Many trials have been carried out using duckweed as the major
feed to raise fish, with good results (Journey et al. 1991),
but, so far, this is fairly rare in Vietnam. The farmers in
the Mekong and Red Deltas and around Ho Chi Minh city use
duckweed as a partial or complete feed for growing fish and
get excellent results. The farmers in the Mekong Delta feed
duckweed to breeding fish to increase reproductive
performance.
Most of the fish species living in fresh water are known to
like to eat duckweed very much, especially Tilapia, carp,
catfish, Mekong catfish, gourami, etc. Duckweed is convenient
and fairly easy to manage because it is grown in the ponds on
stored waste water. It utilises the nutrients and contributes
to a clean environment. Children or women in the households
can take part in managing and collecting duckweed to feed
fish. The farmers can control the amount of feed to the fish
easily by observation and prevent excessive growth, thus
protecting the fishes' environment (personal observation).
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CONCLUSIONS AND SUGGESTIONS
There is no doubt about the role of scavenging ducks, fish and
duckweed in the integrated farming system in Vietnam today.
They produce truly sustainable economic benefits to the
smallholder farmers. The results achieved in the experiments
and practices show that the development is based on scientific
logic under natural and social conditions that avoid damage to
the living environment and improve living standards of the
people, of which 80% are working in the agricultural domain.
Development of scavenging ducks and fish, based on renewable
local feed resources such as duckweed in integrated farming
systems, is an actual revolution and is consistent with the
strategy to eliminate hunger and reduce poverty in the
country. However, in order to make further progress, the
detailed parameters of using scavenging ducks and their
influence on the environment, soil fertility, and other
effects, need to be investigated. There is also a need to look
at which species of fish are most suited to feeding on
duckweed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ACKNOWLEDGEMENTS
This paper is based on studies and findings in Vietnam with
the help of advisers: Dr T R Preston, Dr Brian Ogle and with
the encouragement of Dr Rene Sansoucy, Dr Andrew Speedy, and
Dr Christophe Dalibard. I would like to thank them.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
REFERENCES
Becerra, M., Ogle, B. and Preston T. R. 1994. Effect of
replacing whole boiled soybeans with duckweed (Lemna sp) in
the diets of growing ducks. Livestock Research for Rural
Development. Volume 7, Number 3, 44.8Kb.
Culley, D. D., Jr. and Epps, E. A. 1973. Use of duckweed for
waste treatment and animal feed. Journal Water Pollution
Control Federation. Vol. 45, No. 2, pp. 337-347.
Hillman, W. S., Culley, D. D. and Jr. 1978. The Use of
Duckweed. American Scientist. Volume 66, pp. 442-450.
Journey, W. K., Skillicorn, P. and Spira, W. 1991. Duckweed
Aquaculture - A New Aquatic Farming System for Developing
Countries. The World Bank. 76pp. Washington DC.
Leng, R. A., Stambolie, J. H. and Bell, R. 1995. Duckweed - a
potential high-protein feed resource for domestic animals and
fish. Livestock Research for Rural Development. Volume 7
Number 1, 36 Kb
Men, B. X and Su, V. V. 1991. "A" molasses in diets for
growing ducks. Livestock Research for Rural Development.
Volume 2, No 3.
Men, B. X., Ogle, B. and Preston, T. R. 1995. Use of
restricted broken rice in duckweed based diets for feeding
growing Common and Muscovy ducks. (Unpublished data, Vietnam).
Men, B. X. and Preston, T. R. 1994. Use of duckweed as partial
replacements for protein supplement in diets for feeding
exotic Muscovy ducks. (Unpublished data, Vietnam).
Preston, T. R. 1995. Reserch, Extention and training for
Sustainable Farming Systems in the Tropics. Livestock Research
for Rural Development. Volume 7, Number 2, 84Kb.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FAO ELECTRONIC CONFERENCE:
LIVESTOCK FEED RESOURCES WITHIN INTEGRATED FARMING SYSTEMS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DISCLAIMER: Neither the conference organizers nor FAO accept
any legal responsibility for either the contents of this
message or any copyright laws that the person sending this
electronic message may have violated.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TO COMMENT: Unless you want to reply only to the person
sending this information, please send your comments to the
address: TFCONF2-L@MAILSERV.FAO.ORG
or TFCONF2-ABS-L@MAILSERV.FAO.ORG
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 13 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: PACU
From: Jose Pelleya
Date: Sun, 21 Feb 1999 08:49:23 -0700
I was given this number in Miami:
Pacu Project; Gabriel at 305/274-0450 or 0750
Jose
At 09:29 PM 2/20/99 PST, you wrote:
>
>Any one know of a supplier of Pacu, who is licensed to export, I am
>willing to try this species here in the Caribbean.
>Gordon??
>
>Take care guys,
>Sue.
Thought for the day:
- "The only thing that interferes with my learning is my education."
Albert Einstein
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 14 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: missing URL
From: Jose Pelleya
Date: Sun, 21 Feb 1999 11:30:29 -0700
Does anyone know the URL of a page which has a DIY system which uses a
square Rubbermaid-type container with a system of PVC pipes on top for
nine plants (expandable)?
The system uses the tops of plastic 2 liter bottles (upside down) to hold
the plants, small pump, etc.
Thanks
Jose
Thought for the day:
- "The only thing that interferes with my learning is my education."
Albert Einstein
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 15 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: missing URL
From: Glen Seibert
Date: Sun, 21 Feb 1999 10:52:43 -0800
Jose Pelleya wrote:
>
> Does anyone know the URL of a page which has a DIY system which uses a
> square Rubbermaid-type container with a system of PVC pipes on top for
> nine plants (expandable)?
>
> The system uses the tops of plastic 2 liter bottles (upside down) to hold
> the plants, small pump, etc.
>
> Thanks
>
> Jose
>
> Thought for the day:
>
> - "The only thing that interferes with my learning is my education."
>
> Albert Einstein
Hi Jose!
Yes, its hydroponics on line and the link is at the end of my signature.
HydroRon is a great guy, very helpful and his past communications are
archived. Hes even expanded his files to include a step by step set of
plans for building the little pop bottle system!
--
Glen Seibert
Fullerton College
Hydroponics
http://www.hydroponicsonline.com/club.htm
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 16 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: "Marc S. Nameth"
Date: Sun, 21 Feb 1999 12:29:50 -0700
Hydrogen sulfide is also corrosive to many metals.
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 17 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: request for nutrient supplier
From: Jaarvis
Date: Sun, 21 Feb 1999 15:22:58 EST
they are designed for use in hydroponic systems
it might be possible to use them in an aquaponic scenario though i dont know
if anyone has done in work in this realm
i can ask the chemist this week and see what he says about their application
in aquaponics
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 18 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: Michael Strates
Date: Mon, 22 Feb 1999 18:36:34 +1100 (EST)
On Sun, 21 Feb 1999, jilli and lars wrote:
jal> Almost wherever i go, i try to carry plastic containers
jal> or bags or something that will hold small amounts of liquid. If
jal> i come across a pond, or even a puddle that appears to have
I once took a 50ml water sample from Warringal Parklands, Melbourne. The
results under the microscope outstanded me. Not only was almost every
human pathogen in the water :) [fecal coliforms were RIIIGHT up there],
but I could see strange worms navigating throughout the small bits of
reeds and duckweed in the pond. These strange worms were EATING the little
waterfleas! I never did find out what they were.
jal> world of bacterial genetic information. You are exposing them to
jal> new (an potentially dangerous, i suppose) 'ideas'. You are
You /might/ have a point, however you'll NEVER see me tainting my
aquaponics water with one from another water body.
--
e-mail: mstrates@croftj.net www: http://www.croftj.net/~mstrates
See keyservers for PGP info. Linux! The OS of my Choice!
"Once you have flown, you will walk the earth with your eyes turned
skyward, for there you have been, and there you long to return."
- Leonardo da Vinci, and below an extract from John Fogerty's song:
Hey, Tonight - Gonna be tonight- Don't you know I'm flyin'- Tonight
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 19 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Lettuce Harvesting Idea
From: Michael Strates
Date: Mon, 22 Feb 1999 18:41:03 +1100 (EST)
How about a vacuum cleaner motor with its front guard removed (and cleaned
of course :) strung up onto a track above the grow bed, and then can be
hand pushed along harvesting the lettuce, and shooting the cut greens down
some hosing, and possibly spraying them with water at the same time?
We used to use our Flymo (brand of electric rotary lawnmower) for
harvesting looseleaf lettuce. Just set the height right, "mow" the lettuce
and you have, in the catcher cut greens. Make sure you don't use a gas
mower for this (taint it with gasoline taste :) and to clean the mower
well before attempting it. Naturally, this won't work well with raised
beds.
--
e-mail: mstrates@croftj.net www: http://www.croftj.net/~mstrates
See keyservers for PGP info. Linux! The OS of my Choice!
"Once you have flown, you will walk the earth with your eyes turned
skyward, for there you have been, and there you long to return."
- Leonardo da Vinci, and below an extract from John Fogerty's song:
Hey, Tonight - Gonna be tonight- Don't you know I'm flyin'- Tonight
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 20 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: Michael Strates
Date: Mon, 22 Feb 1999 18:32:35 +1100 (EST)
On Sun, 21 Feb 1999, jilli and lars wrote:
jal> I know the stuff smells kinda funky, but it's not
jal> dangerous is it? And why the concern for venting 'precious
jal> sulphur"? Isn't sulphur generally abundant?
Hydrogen Sulphide is about one of the most toxic inorganic gases one could
make whilst composting. Once you can smell H2S, the level is waaay over
the EPA recommended ones. After being in a room that "stinks" of H2S for a
few minutes, and you don't smell it anymore - its a mega warning sign,
because the hydrogen sulphide has desensitized your snozzle :)
jal> The more biological activity means the more processes
jal> your molecules are going through, which means the more likely
jal> they are transformed from something manufactured by humans into
jal> something that has been biodegraded into harmlessness or
jal> usefullness by macro-organisms.
Like I said.. Vapours of NH3 and H2S are the things we need to stop. NH3
causes headaches, and is a general irritant, and H2S is very, very
poisionious.
--
e-mail: mstrates@croftj.net www: http://www.croftj.net/~mstrates
See keyservers for PGP info. Linux! The OS of my Choice!
"Once you have flown, you will walk the earth with your eyes turned
skyward, for there you have been, and there you long to return."
- Leonardo da Vinci, and below an extract from John Fogerty's song:
Hey, Tonight - Gonna be tonight- Don't you know I'm flyin'- Tonight
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 21 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: uweb@megalink.net.mx
Date: Sun, 21 Feb 1999 19:05:45 -600
>Hydrogen sulfide is also corrosive to many metals.
>
Like which? Wouldn't like to use them for the tubing. - Uwe
http://www.megalink.net.mx
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 22 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: doelle
Date: Mon, 22 Feb 1999 14:48:53 +1100
Lars,
It all depends on the amount released and whether is steadily released. It
certainly can become a health hazard or do you want to run around with a
constant headache ? The amount is the concern. If it is small, ok. If nobody
lives around, it may be ok. I am surprised to learn that you are not so
concerned about air pollution.
Good luck Horst
.------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
| Message 23 |
'------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
Subject: Re: good bacteria
From: doelle
Date: Mon, 22 Feb 1999 14:52:29 +1100
Lars,
Where on earth do you get those ideas from ? Bacteria just can grab genes
from the air or environment ? Gene transfer in nature without mul;tiplication ?
Please give me your source of information. As a microbiologist I am very
concerned about your 'bacterial philosophy'.
Horst
S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775 417-256-5124
Web page http://www.townsqr.com/snsaqua/
|
