Azolla News
Revised on 05.7.17
CONTENT
The use and import of non-native Azolla will be regulateed by "Invasive Alien Species Act"
Since July 2005, "Invasive Alien SpeciesAct" was promulgated.
Related site
Ministry of Environment asked botanists experts to decide such invasive plants.
They agreed to include Azolla cristata as "Invasive plant"(2005.7.14).
Japanese experts of using Azoola for rice-duck farming recommended to use a hybrid line.
This line is excluded from the regulated invasive Azolla species. So, the use of Azolla is possible.
The regulation will be implemented early next year.
Prof. Van Hove clarified Taxonomy of New World Azolla species
The taxonomy of the New World Azolla species has been debatable and unsatisfactory. Particularly, the identification of three "species" -
A. mexicana, A. caroliniana, and A. mexicana have been difficult . Prof. Van Hove and C. Evrard, Universite Catholique de Louvain conducted comprehensive review
of the literature and original observation of harbarium and cultivated samples.
They revealed the ferns named A. caroliniana and A. microphylla by most authors are different from their type specimen.
Also observation of type specimen clarified A. microphylla and A. caroliniana are synonyms of the previously described A. filiculoides.
To clarify these problems, Belgian botanists proposed to rehabilitate Mettenius concept, proposed as early as 1867: "two specied only exist in America; A. cristata
and A. filiculoides.
The table of Azolla species is revised according to this concept. See
Reference: Evrard C. and Van Hove C. (2004) Taxonmy of the American Azolla species(Azollaceae): a critical review Systematics and Geography of Plants 74:301-318
Azolla (Use) revived in China
Fourth Asian Symposium on Rice-Duck System was held in Zhengjiang, Jiangsu, China on 19~21 July,2004.
Scientists, experts, and farmers got together from China, Korea,Japan, and some Asian Countries. During field observation tour, the demonstration plots of Rice-Duck-Azolla System werereviewed as one of variation of Rice-Duck System.
"This is revival of Azolla use in China" claimed experts on Azolla use , Dr. Liu Chungchu,(Fujiang, China) Tang longfe(Fujiang, China),
and Iwao Watanabe (Japan) unanimously.
Azolla had been widely used until the middle of 1980s, but it declined due to availability of fertilizers.
However, Prof. Liu Chungchu and his colleagues continued the use as supplement of
Rice-Fish system in mountainous regions of Fujiang. Conbination of Azolla to Rice-Duck System was based from
the similar idea of multiple use of Azolla.
Apparently, the use of Azolla in Rice-Duck System in Jiangsu,China was technically assisted by National Azolla Research center in Fujiang.
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| Azolla on the surface iused as nitrogen fertilizerj1978, Jiangsu Province? |
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| Azolla in Rice-Duck System July 2004 at Zhengjiang, Jiangsu |
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8. Unexpected bloom of Azolla in ponds reported in Japan(2003.6)
Recently, unexpected bloom of azolla in ponds has been reported mostly in western parts of Japan. The bloom looks red, and gave surprize to the people nearby. Often local newspaper picked up this bloom.
Azolla started spreading from 2002 to 2003 in a pond (Inuma Pond - about 2.5 ha) at Kakegawa City, Shizuoka Prefecture
1) From 2002 summer, sporadic spreading of Azolla japonica (Probably Azolla filiculoides) was observed. Up to October, almost entire surface of the ponds was covered by red layer due to Azolla. The full cover might have induced quality damage of pond water, trigering concern by people nearby (Figures 1, and 2)
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Fig.1 Azolla covers fully the surface of ponds
2002.5.11 Photo by Mineo Ohta
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Fig.Q Collecting Azolla, pushing by bamboo poles to one side
2002.5.13 Photo by Mineo Ohta
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2) In May 2003, a TV Company picked up the removal work of Azolla, almost manually by TV actors and local people. Collected Azolla about 200 cubic meter was heaped nearby. At the end of May, 3 weeks after the removal, Azolla still remained at the edge of the pond. Oversummering needs careful observation.
From the morphological features, the fern was identified as Azolla filiculoides. If it was indigenous or imported is not clear.
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Fig.R Azolla heap
Photo at 26 May, 2003
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Fig.S Remaining Azolla
Photo at 26 May, 2003
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3) Overgrowth of Azolla in small ponds has been reported quite often in Japan and other parts of world.
Particularly, Azolla filiculoides, being big and forming thick mat, tends to be hazardous to the environment.
The use of this species should be carefully managed to avoid unexpected spreading.
Indigenous Azolla (A. japonica and A. imbricata) are
registered as "endangered species" in Japan.
As some of introduced Azolla have higher agronomic value than indigenous ones,
blind rejection of introduction of foreign species is not productive. Researchers suggest to use
hybrid accessions to avoid takeover and genetic disturbance.
The bloom disappeared after summer of 2003
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7. World experts visited Japan, and convinced of Azolla-Rice-Duck system(2002.12)
An expert on Azolla, Dr. Prof. C. Van Hove, Univeriste Catholique de Louvaine,
visited Japan in 2001, and observed T.Furuno's farm, and Y. Kishida at experimental fields in Okayama University, and highluy impressed
with their farming systems and philosphy behind them.
He admired the trmendous efforts and recognized almost first nationwide successful trials of azolla use in farmers fields.
He summarized the application of Azolla, including the experience by T. Furuno in his review paper, recently published.
Van Hove C. and Lejeune A. 2002 Applied aspects of Azolla-Anabaena symbiosis.
In Cyanobacteria Synthesis (Rai A.N., Bergman B. and Ramussen U. eds) Kluwer Academic Publishers . Dordrecht, pp 179-193
Dr. Li Chung-chu, a former Director general of Fujian Academy of Agricultural Sciences, Peoples Republic of China, visited Japan in 2002, and similarly felt.
He initiated immediately research project in China,to disseminate Azolla-Rice-Duck Farming in cooperation with Dr. Y.Kishida.
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6. English edition of Furuno's writing about Rice-Duck system was published
 | Publisher TAGARI Publications,Australia
Website www.tagari.com
Price 24US$
Details of chapters are seen here | |
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5. PhD by the study of rice-fish-azolla-duck farming systems in the Philippines
Arsenia G. Cagauan of The Central Luzon State University, Philippines, received phD degree for her work on fish-azolla-duck integration to rice farming.
Under the advice of Prof. Van Hove, Universite Catholique de Louvaine, Arsenia G. Cagauan of The Central Luzon State University, Philippines, received phD degree in June 1999.
The thesis title is:
Production, economics and ecological effects of Nile tilapia (Oreochromis niloticus L.),
a hybrid aquatic fern azolla (Azolla microphylla Kaulf X Azolla filiculoides Lam.) and
mallard duck (Anas platyrhynchos L.) in integrated lowland irrigated rice-based farming systems in the Philippines.
The major findings are;
1) Rice yield increased significantly (58%) in rice-fish-azolla-duck system over conventional rice monocropping.
2) Tilapia production was also increased 33% in combination with azolla ,
1.9 times with duck, and 2.2 times with azolla and duck over conventional rice fish system.
3) Net economic return increased 64% with Tilapia culture over conventional rice monoculture.
In duck systems, net return increased 11-12 times in combination with fish-azolla or fish alone over conventional rice monoculture.
4) Duck herding, particularly before transplanting rice was effective in eliminating golden apple snail.
5) Weeding effects of duck and azolla were confirmed.
6) The inegration azolla alone did not increase much aquatic Oligochaeates, feed for fish, population, but further integration of duck was more effective in increasing this population, leading to favorable conditions for fish.
7) Physico-chemical properties of wetland rice soil was also significantly affected by these integration systems.
Thus, the research demonstrated general positive effects of the integration of Nile tilapia, azolla, and mallard duck on the production, economics, pest control and rice field ecology of rice-based farming system. The achievement is relevant to small-scale rice farmers in the Philippines, and addressed the importance for sustainability in rice farming.
The results will be published in scientific papers.
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4. About A. japonica
Recent studies showed that there are at least two types in A. japonicaiYamato and Tajima types).
The former is not distinguishable from a type specimen of A. filiculoides (FI1001), and distributed in narrower area.
Taxonomical position of the latter needs further elucidation.
The report was published.
WATANABE Iwao, Manami SAWAMOTO, Akiko NAKAGAWA, Yasuo KOWYAMA and Takeshi SUZUKI (1999)
Diversity of Azolla japonica in Japan, analyzed by random amplified polymorphic DNA.
Journal of Japanese Botany 74{3):142-149
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3. Revival of Azolla use in Vietnum integrated with rice-duck farming
I visited Vietnam on Aug. 1-8 to participate in
the 3rd Asian Rice-Duck Farming Sympossium, held in
Hanoi Agric. University.
From Japan, 26 delegates attended, including
researchers, school teachers, farmers, and business persons related to duck rearing.
This symposium was to discuss the application of Rice-Duck Farming
system in Asian countries.
Farmers, researchers, and government officers from Korea, Japan, Malaysia, Thai, Indonesia, India and Vietnam attended.
Direct contact among rice farmers was one of purposes of this symposium
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In northern Vietnam, rice -duck farming is already spreading near Hai Phong.
Dr. Vo Tong Xuang, a former IRRI Board of Trustee, also attended this symposium,
and is pushing this farming in Vietnam.
During the symposium, I made presentation regarding the Azolla use in 1979.
,showing slides taken during my trip to north Vietnam in Jan. 1979 .
Vietnam people highly appreciated my presentation. They almost forgot
the past history of Azolla use, and got fresh impression, knowing their past.
The reseach on Azolla now completely disappeared in Vietnam, and the researchers
who studied Azolla at that time are also forgotten.
Azolla strains they kept were lost.
When azolla was used for rice culture until 1980, the combination to rice-duck
culture was not considered.
First, rearing duck during rice growth was not allowed. Duck was allowed to enter into
rice fields only before or after rice growing period.
Second, indigenous azolla (A.pinnata) could not grow in hot summer period.
The rice-duck farming system was introduced to north Vietnam in 1994 by Mr. Furuno.
The system has been spreading to farmers fields first in Hai Phong area, then in other areas.
Based on the success of combining azolla use to this system by Furuno, and others in Japan,
azolla use to this farming was also introduced by Furuno and JIVC
(Japan International Volunteer Center) in 1998.
Some azolla strains (details unknown) introduced from Furuno could
over-summer well, and now used in Hai Phong district in rice-duck farming system.
If Vietnamese scientists start studying azolla again, IRRI's azolla collections
would find their place to work.
Then, the significance of maintaining azolla strains would be exemplified.
After visiting Vietnam, I felt myself very fortunate, being rewarded to long years effort of
studying azolla.
See:Scenery of using Azolla as rice greenmanure
at northern Vietnam in 1979
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2. Workshop on azolla use to rice-duck culture was held in Fukuoka, Kyushu, Japan.
More than 100 participants joined, indicating increasing interest in using azolla for rice farming in Japan.
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P. Scientific research on Azolla-Rice-Duck system is in progress
Prof. S. Manda, Fac. Agric. Kagoshima University, and Prof. Y. Kishida, Fac. Agric. Okayama University initiated studies. They could show positive effects of growing duck, and duck and azolla to
rice growth, insect damage reduction, herbicidal effects, and nutritive values of azolla to duck.
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