Azolla : A potential biofertiliser for rice

Priyanka Irungbam, L Nabachandra Singh, KS Shashidhar, Yumnam Sanatombi, Y Bebila *

The genus Azolla belongs to the single genus family Azollaceae. There are six species of Azolla ľA. caroliniana, A. nilotica, A. filiculoides, A Mexicana, A. microphylla and A. pinnata. Out of these, A. filiculoides, A. Mexicana, A. microphylla and A. caroliniana, belong to the sub-genus Euazolla.

The two species under subgenus Rhizosperma are A. nilotica and A. pinnata. A. pinnata is the most common species found in India. Azolla has been of interest to botanists and agriculturists for years because of its symbiotic relationship with a nitrogen-fixing, blue-green alga, Anabaena.

The delicate fern provides nutrients and a protective leaf cavity for the Anabaena, which in turn provides nitrogen for the fern. Under suitable field conditions, the fern-alga combination can double in weight every 3 to 5 days and fix atmospheric nitrogen at a rate exceeding that of the legume- Rhizobium symbiotic relationship.

Azolla can accumulate 2 to 4 kg N ha-1 d-1 (equivalent to 10 to 20 kg of ammonium sulphate), and since the Azolla-Anabaena combination grows in aquatic conditions, it can be a potential nitrogen source for flooded crops such as rice.

Benefits of Azolla

1. Azolla (Kang) used for fertilizer management, is one of the most promising biofertilizers for a variety of crops, including rice, wheat, taro and soybean. Its application improves soil fertility by increasing total nitrogen, organic carbon and available phosphorus in the soil.

2. It is used as a food supplement, fresh, dried or ensiled, for a variety of animals, including pigs, rabbits, chickens, ducks, and fish. Azolla contains essential amino acids, vitamins (Vitamin A, Vitamin B12 and betacarotene), growth-promoting intermediaries and minerals like calcium, phosphorous, potassium, ferrous, copper and magnesium.

3. It suppresses the growth of aquatic weeds by blocking sunlight and providing a physical resistance to weed seedling emergence by creating a heavy, interlocking, azolla mat.

4. It can also be used in the control of mosquitoes. A thick Azolla mat on the water surface can prevent breeding and adult emergence.

5. It plays an important role in ecosystem management including bioremediation of toxic trace metals and organic pollutants. It can act as a bio-filter to remove pollutants. Azolla live biomass acts as potential bio-accumulator for toxic pollutants, while the dead biomass regulates pollutant concentration through bio-sorption.

6. Its application can minimize greenhouse gas (GHG) emission from agriculture as well as mitigate atmospheric GHGs.

The characteristics that make Azolla suitable as a biofertilizer on rice are as follows:

1. A shallow, freshwater habitat such as that found in a flooded rice field is the ideal environment for Azolla.
2. Azolla fixes nitrogen at a substantial rate.
3. Azolla has rapid growth.
4. Since Azolla floats on the water surface, it cannot compete with rice for light and space.
5. In most climates, Azolla grows best under a partial shade of vegetation, which a rice canopy, in its early and intermediate stages of growth, can easily provide.
6. When rice approaches maturity, due to low light intensity under the canopy and depletion of nutrients, Azolla begins to die and decompose, thus releasing nutrients into the medium.

7. Azolla decomposes rapidly, and therefore, the nitrogen it has fixed and the phosphorus and other nutrients it may have absorbed from the water, perhaps in competition with the rice, are rapidly released back into the medium and made available for uptake by rice during grain development.

8. Azolla has a greater ability than rice to accumulate potassium in its tissues in low potassium in its tissues in low potassium environments; thus, after decomposition, it makes this nutrient available to rice.

9. In contrast with chemical nitrogenous fertilizers, Azolla has long-term residual effects, in particular, the improvement of soil fertility by increasing total nitrogen, organic carbon, available phosphorus, potassium, and other nutrients.

10. If chemical nitrogenous fertilizers are applied, an Azolla mat reduces the volatilization of ammonia that normally occurs.
11. A thick Azolla mat in a rice field has the side-benefit of suppressing weeds.

Azolla production technology

Azolla production technology is simple and not very expensive, and at the same time, it is very efficient in terms of biomass accumulation and nitrogen fixation. The rice-growing season is also conducive for the growth of Azolla plants. The most common mode of application of Azolla in the field is as green manure or as a dual crop along with rice.

In case of application as green manure, Azolla collected directly from nursery plots, ponds, ditches, canals etc. is applied in the field. A thickmat of Azolla will be formed after application in about 2-3 weeks and can be incorporated in the soil. Rice can also be transplanted in the field subsequently. Single super phosphate (25-50 kg ha-1 is applied in split doses).

Azolla application by this mode contributes around 20-40 kg N ha-1. In dual cropping, Azolla is grown along with rice and each crop of Azolla contributes on an average 30 kg N ha1. After 7-10 days of transplantation, fresh inoculums of Azolla are applied in the field at the rate of 0.50-1.0 ton ha1.

Single super phosphate is applied at the rate of 20 kg ha-1 in split doses. In about 15-20 days, a thick mat of Azolla is formed. Azolla, thus incorporated, decomposes in about 8-10 days and releases the fixed nitrogen. Another crop of Azolla can be raised in a similar way during the crop cycle of rice.

The dual application does not have any negative influence on the rice crop. The most effective application for increasing soil fertility is to first culture Azolla as a monocrop in the fallow period without diminishing the rice-growing period, incorporating it before transplanting and subsequently culturing it as an intercrop with two incorporations.

Azolla production can be carried out in nursery plots, ponds, ditches, canals, concrete tanks, polythene lined ditches and even paddy fields. The field selected for Azolla cultivation needs to be thoroughly prepared and leveled uniformly.

Generally, 20m x 2m size plots are made in the field with suitable bunds and irrigation channels with a water depth of at least 10 cm and each plot is filled with water (20 liters) and inoculated with Azolla (8-10 kg).

Single super phosphate (100 g) in 2-3 split doses is applied to each plot at an interval of 4 days. Furadon or carbofuran (3% active granules) can be applied in the plots (100 g plot-1) with or after a week of inoculation. 100-150 kg fresh Azolla can be harvested from each plot after 15 days. The same method can be used to produce Azolla in bigger plots.

Cultures of Azolla must be maintained in nurseries throughout the year. The water should be changed or cold water added if the water temperature rises above 35oC. For adequate growth during field cultivation, the daytime water temperature should stay within the range of 15-35oC. Very high humidity and high temperature or very low humidity and low temperature are both detrimental to the growth of Azolla.

Azolla grows best within a pH range of 5 to 7 and can survive a range of 3.5 to 10.


The application of Azolla as a biofertilizer on agricultural crops, reducing or replacing chemical fertilizers, can play a significant role in maintaining or improving ecological balance. Utilization of Azolla in agriculture also improves socio-economic status by reducing the agricultural input cost, generating employment opportunities for small-scale industry involved in its propagation.

Azolla can also reduce the energy demand for fertilizer production, thus, reducing the impact on environment due to energy production. Considering its various uses, it can, therefore, be concluded that Azolla is a multi-faceted biofertilizer which will help in attaining sustainability in crop production.

Department of Agronomy,
College of Agriculture,
CAU, Imphal

For further details contact:
Public Relation & Media Management Cell,
CAU, Imphal

* Priyanka Irungbam, L Nabachandra Singh, KS Shashidhar, Yumnam Sanatombi, Y Bebila wrote this article for The Sangai Express
This article was webcasted on December 22 2020.

* Comments posted by users in this discussion thread and other parts of this site are opinions of the individuals posting them (whose user ID is displayed alongside) and not the views of We strongly recommend that users exercise responsibility, sensitivity and caution over language while writing your opinions which will be seen and read by other users. Please read a complete Guideline on using comments on this website.

  • 'Solution expected anytime soon'
  • COVID-19 vaccination [Jan 16] #2 : Gallery
  • COVID-19 Status 17 Jan : Govt of Manipur
  • Niangngaihkim, Thangneh: eMing
  • Bhuban cave: Holy place of TRC people #1
  • Police Guest House CCpur : Gallery
  • Know-how for using herbicides in rice
  • Too much too good ?
  • Roll up the sleeves for Covid shot
  • COVID-19 vaccination [Jan 16] #1 : Gallery
  • COVID-19 Status 16 Jan : Govt of Manipur
  • Empowering women through sports
  • COVID-19 : Impact in Manipur :: News Timeline
  • Dzuko 'the Nagmani'
  • 3rd foundation day- National Sport University
  • Research & Publication Ethics Workshop
  • Living Legends of Manipur : Wall Calendar
  • Cong existence felt, will it survive?
  • Day light Thabal Chongba #3 : Gallery
  • COVID-19 Status 15 Jan : Govt of Manipur
  • School Fagathanshi @Leimapokpam: Gallery
  • The voice inside me :: Poem
  • Let's embrace youths self esteem
  • Gita - An antidote for life in Kali #2
  • Bedtime beauty hacks to look young
  • Menace on the roads of Imphal
  • Hill Valley bondage strengthened
  • Narcotic Drugs disposal @Lamlai #1 : Gallery
  • COVID-19 Status 14 Jan : Govt of Manipur
  • Shachi Gurumayum honoured overseas Indian
  • Enthusiasm of LFCA's children
  • Energy Conservation Material Management
  • Commandant 12th Bn NDRF called on CM
  • Water education for sustainability
  • Postpone Public Hearing on Gender Policy
  • Students at the forefront
  • Fuelling the anger
  • COVID Vaccine arrived @ Airport : Gallery
  • Major (Dr) Laishram Jyotin, Ashoka Chakra
  • Mushroom training program at Langmeidong
  • 5 years of Pradhan Mantri Fasal Bima Yojana
  • Drugs ki lansu amani
  • 3rd State Level Jump Rope Championship
  • Vaccine and low count of infection
  • Human fails to learn lessons from Corona
  • My memories of Imphal from 1941 #13
  • COVID-19 Status 12 Jan : Govt of Manipur
  • National Youth Day at Lilong Haoreibi
  • Face it all together: threat of pandemics
  • Majuli - India's only river island district
  • More of a question when, not should
  • Tungjoy re-visited
  • COVID-19 Status 11 Jan : Govt of Manipur
  • COVID Vaccination Meeting with PM: Gallery
  • Fruits & Vegetables grown in North East #2
  • 18th BIG Call : Biotechnology Grant
  • Trade hate for love : Blissful 2021
  • Jump Rope (Judges & Referees) Exam
  • Connecting via Jiri
  • Dhanamanjuri University & its Identity Crisis
  • INA's Honour at the Battle of Imphal
  • COVID-19 Status 10 Jan : Govt of Manipur
  • Ima Keithel @ Kanglatongbi/Sekmai : Gallery
  • Aromatic Oil Extraction training at Huishu
  • Tulihal - Our sweet old local airport
  • Gita - An antidote for life in Kali #1
  • Training on Mushroom at Nagamapal
  • The call for new normal still stands
  • 187 Death Anniv- Maharaj Gambhir : Gallery
  • COVID-19 Status 09 Jan : Govt of Manipur
  • Biocontrol of Parthenium for biodiversity #2
  • A message from mother nature :: Poem
  • New year resolution & complication
  • NEP-2020 : A new Landscape in Education
  • Wildfire in Dzuko, Senapati #1 : Gallery
  • COVID-19 Status 08 Jan : Govt of Manipur
  • Satyamala : Most Fortunate Manipuri Princess
  • Transforming economy of the kingdom of God
  • Events and celebration as career
  • How to protect your lips in winter
  • Poppy plantation & drug trafficking
  • We Continue To Strive Forward
  • Press Club Foundation Day : Gallery
  • COVID-19 Status 07 Jan : Govt of Manipur
  • Bereavement : Grief Reaction
  • Emergency Response System : Gallery
  • This world :: Poem
  • Bitter truth
  • Re-opening and rethinking border trade
  • My memories of Imphal from 1941 # 12
  • COVID-19 Status 06 Jan : Govt of Manipur
  • Fruits & Vegetables grown in North East #1
  • Life goes on !
  • Naga Rapper Macnivil - New Music Video
  • Awareness Prog with Women Commission
  • Farm Acts need of the hour
  • Imphal on eve of New Year 2021 #2 : Gallery
  • COVID-19 Status 05 Jan : Govt of Manipur
  • Cold Storage @ Bishnupur Bazar : Gallery
  • Pronoia - The sociological antidote to corona
  • New Year 2021 :: Poem
  • Careers opportunity in Fashion Industry
  • Economic growth: A mirage so far
  • The law of Habit
  • Zeilad Lake in Tamenglong #1 :: Gallery
  • COVID-19 Status 04 Jan : Govt of Manipur
  • Biocontrol of Parthenium for biodiversity #1
  • Child Nutrition and their future
  • Guilt free self love - Not a sin!
  • 'Anguish over wild fire at Dziikou Valley'
  • Another message for another year
  • Lamphelpat: Victim of unplanned urbanisation
  • Politics and the War Against Drug
  • Ibudhou Marongkhong Haraoba #4 :: Gallery
  • COVID-19 Status 03 Jan : Govt of Manipur
  • Eyek Tamba :: Learn the Manipuri script
  • Linguistic Society of America 2020 to Manipur
  • Time for Modi-Shah duo to ink the final pact
  • Vanishing Lamphelpat calls for conservation
  • New Community Centre at Ningthoukhong
  • Disturbed Area status: An unwelcome gift
  • Paona Independence League of Burma #3
  • COVID-19 Status 02 Jan : Govt of Manipur
  • Presentation of Tourism in Manipur : Gallery
  • Manipur's super cops
  • The passing moment- clock of life :: Poem
  • Executive Committee of 2021-22 YMC
  • Take care of your hands this winter
  • RK Bhubonsana : Profile- Literature Awardee
  • COVID-19 Status 01 Jan : Govt of Manipur
  • Prayers to honourable Home Minister
  • Book Release of Cheerom Meihoubarol
  • Chronicling activity of Veterans in Manipur #2
  • Biswajit Basu as Director (Projects), NHPC
  • Imphal on eve of New Year 2021 #1 : Gallery
  • COVID-19 Status 31 Dec : Govt of Manipur
  • Downloadable Manipuri Calendar :: 2021
  • Featured Front Page Photo 2020 #6: Gallery
  • Bidding Goodbye 2020 with a toast of Corona
  • Let us not down NK Sanajaoba's Spirit
  • Dr Konika Khuraijam- SDP Achievers Award
  • One Day Adventure Programme at Lamdan
  • On stepping into a brand New Year
  • Welcome 2021: Will it be another happy days
  • Romita Yumnam is Mrs Jhansi 2020 : Gallery
  • COVID-19 Status 30 Dec : Govt of Manipur
  • Mrs Romita Yumnam crowned Mrs Jhansi 2020
  • Year's End - 2020 :: Poem
  • Bye - Bye 2020 :: Poem
  • Maya Kuki in top 25 in Mrs Universe 2020
  • 2020: Decisive for the BJP in Manipur
  • The other side of Amit Shah & Manipuri talent
  • My memories of Imphal from 1941 #11
  • COVID-19 Status 29 Dec : Govt of Manipur
  • The cry of a disgruntled citizen
  • KVRSS Annual Research Awards 2020-21
  • Manage to reduce it
  • Life is a matter of choices
  • Painting Competition : Right to Information
  • New virus strain: The world is worried
  • Mayang Imphal Keithel #1 : Gallery
  • COVID-19 Status 28 Dec : Govt of Manipur
  • January Calendar for Year 2021 : Tools
  • Shanti Thokchom #43 : Trip to Grand Canyon
  • Naga Peace Process :: News Timeline
  • 2020 as the 'Year of Science'
  • Sampurna Raas Leela at Guwahati
  • Significant 2 hours delay in leaving lmphal
  • Biren will be Chief Ministerial candidate
  • Amit Shah @Imphal [Dec 27] : Gallery
  • COVID-19 Status 27 Dec : Govt of Manipur
  • Organic cultivation of tomato
  • Xmas during pandemic - a time to reflect
  • Reviews of Loktak Downstream Project
  • Amit Shah: Man behind ILP in Manipur
  • S Lonphai, Henglep Sub-div, CCpur : Gallery
  • COVID-19 Status 26 Dec : Govt of Manipur
  • Christmas greetings
  • Halls of Ivy - a lament :: Poem
  • Remembering Jesus- A lonely 'Carpenter'..
  • Beauty oils: The solution for dry winter skin
  • Of Manipur and HM visits
  • Works of Haobam Paban Kumar #2 : Gallery
  • COVID-19 Status 25 Dec : Govt of Manipur
  • Pukhrambam Narjit : Asangbi Sanagi Medal
  • Community health work is work
  • Chronicling activity of Veterans in Manipur #1
  • What are friends for ?
  • Discontinuation of Traditional Elopement
  • Christmas Traditions :: Book
  • Lessons from COVID-19: Universal healthcare
  • Getting bronze medal in drinking
  • Manipur on the way to development
  • Towards Atmanirbhar Cities
  • NSCN (K) in talk mode
  • Still murky news from Manipur University
  • Paona Independence League of Burma #2
  • COVID-19 Status 23 Dec : Govt of Manipur
  • Christmas 2020: Pandemic time Choice
  • Winter woods :: Poem
  • Cultivation practices of Soybean in Manipur
  • Laishram Mema honoured at Mumbai
  • Blow out the old, ring in the new
  • My memories of Imphal from 1941 #10
  • COVID-19 Status 22 Dec : Govt of Manipur
  • School Fagathanshi Mission : Gallery
  • Yongchak: The Dying Bean in Manipur
  • Economy of using concrete transmission line
  • Careers opportunity in Journalism
  • The reality: Virus is still out there
  • Are we in the right direction
  • Khamba Thoibi Jagoi at JNMDA #1: Gallery
  • COVID-19 Status 21 Dec : Govt of Manipur
  • 84 yrs recovers from C0VID-19 at Ukhrul
  • Azolla : A potential biofertiliser for rice
  • Rice water for winter beauty
  • Boring 2020
  • War on Drugs campaign : Drawing attention
  • War on Drugs: The uncheck loopholes
  • Cherry Blossom at Mao #1: Gallery
  • COVID-19 Status 20 Dec : Govt of Manipur
  • CM visit to Senapati: Gallery
  • As the year comes to an end :: Poem
  • This too shall pass
  • A tribute
  • No test for incoming passengers
  • ILMDG's approach to preserve Ariba Pala
  • COVID-19 Status 19 Dec : Govt of Manipur
  • Manipuri Filmmaker @ 51st Intl Film Fest India
  • Revisiting the life of Lamyanba NK Sanajaoba
  • 5 days skill development training program
  • Symposium on Combating COVID-19 : Day 3
  • The art of cleaning the dirt
  • Festive mood in CCpur for Xmas: Gallery
  • Panti Neimei : Prayer for longevity
  • New species of lac insect found in Manipur
  • Irang bailey bridge @ Noney : Gallery
  • Ningol Chakouba @ Thanga #2: Gallery
  • Persons with Disabilities [Dec 15] : Gallery
  • ADR Centres at 5 districts : Gallery
  • Works of Haobam Paban Kumar #1 : Gallery
  • State level Nupi Lan Day : Gallery
  • Langban Lam-Haiba @ Andro #2: Gallery
  • Sory Wahengbam - Actress Gallery :: eRang
  • COVID patient cast vote @Wangoi : Gallery
  • 'Zehara' - Manipuri Movie :: eRang Classic