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Azolla: A New Paradigm of the Future of Rice

Mariano Montano's picture

My research in Azolla-Anabaena (AA) began in 1980, when I joined the Institute of Chemical and Environmental Sciences at Escuela Superior Politécnica del Litoral (ESPOL) in Guayaquil, Ecuador. After many years of research and testing with various partners, the World Bank’s Development Marketplace funded “Converting Rice Fields into Green Fertilizer Factories” in 2008. I would like to share with you the successes of this project, which has the potential to change the paradigm of rice production in Ecuador.


Rice in Ecuador is an essential and primary food for most of the population. The country harvests more than 300,000 hectares involving more than 140,000 families. Therefore it is important that rice is produced cost-effectively and in an environmentally sustainable manner. The production costs of rice depend on the type of seed, fertilizer and phyto-sanitary package used to control weed and insects, costs of labor, land preparation, rental equipment for seeding and harvest, and irrigation. The majority of fertilizers are chemical-based, involving heavy imports and causing environmental problems. More than 40% of the fertilizer applied is released into the environment, as plants cannot utilize 100%. In addition, purchases of imported chemical fertilizers for agriculture account for about 30% of current production costs.

The application of artificial nitrogenous fertilizer in rice cultivation represents drain of foreign exchange. It also contaminates the soil, surface water and groundwater, affecting the development of beneficial flora and fauna, and decreasing productive potential of the land in the long term. This situation creates a great need and at the same time opens a huge opportunity for an alternative fertilizer based on native resources, like AA, and its technical application.

Principal achievements

Azolla-Anabaena (Figure 1) is a tiny floating fern with small alternating leaves and simple roots that hang beneath the water; the cavities of its leaves shelter microscopic nitrogen-fixing Anabaena cyanobacteria (Figure 2. The AA symbiotic relationship represents a proven green bio fertilizer for rice (Figure 3) and many other Ecuadorian crops, such as bananas (Figure 4).
Figure 1 Figure 2
Figure 3 Figure 4


For centuries the Azolla-Anabaena fern has been traditionally used as a green fertilizer for rice in the lowlands of Vietnam and China, playing an important role in the economy of these countries. In the last 70 years, commercial agriculture globally has increased dependence on artificial chemical fertilizers, a technologically costly approach which is not sustainable and adversely impacts the environment and public health.

This project has permitted the cultivation of rice with the exclusive use of Azolla-Anabaena as a fertilizer. The trials produced an average production of 4.06 t/ha, an impressive result considering that the national average is 3.14 tons/hectare. Additionally, Azolla improves water quality, soil quality, and the health of workers.

As a result of project fieldwork, seminars, press, radio, television and internet, many citizens now recognize AA as a natural, sustainable and economic alternative to synthetic fertilizer.

Looking towards the future

My new goal is to extend Azolla-Anabaena to more sites, so that eventually it is used in all national rice cultivation, which covers some 400,000 hectares and affects over 140,000 families.

The Azolla-Anabaena story is now unfolding on many different levels in many places. The development and spread of AA in the Guayas Ecosystem (Figure 5) introduces a new paradigm of “tropical knowledge”.

The incorporation of Azolla into rice cultivation in the Guayas Ecosystem will play a strategic role in Ecuador as it will also provide fertilizer for agriculture, food for livestock, water treatment for the Daule, Babahoyo and Guayas Rivers, aquaculture industry improvement in the Guayas Estuary, fisheries stimulation in the Gulf of Guayaquil, soil enrichment, biota recovery, and carbon credits. In fact, several farmers, businesses, and projects focused on rice cultivation, banana cropping, cocoa plantations, cactus cultivation, pig farming and urban agriculture have begun to adopt Azolla in their farming practices.

Figure 5. Azolla: A powerful lever for transforming rice cultivation in Ecuador

Figure 5

In this table, I have also estimated the potential annual economic savings of using Azolla in agriculture, and related goods and services in Ecuador.
Product/Service US$
Fertilizer for agriculture  313  The ecosystem of rice farms along the coast has the capacity to produce fertilizer for all of Ecuadorian agriculture.
Food for livestock  200  The high protein content of Azolla makes it ideal as animal feed.
Water treatment  120  The use of Azolla in rice cultivation will serve as an immense and extraordinary natural water filter for the Daule, Babahoyo and Guayas Rivers.
Aquaculture improvement  150  The purified water will play a substantial role in increasing the value of shrimp mariculture.
Fisheries  60  Fish stocks and catch will increase in the Gulf of Guayaquil due to improving water quality.
Soil enrichment  20  Soil texture, porosity and organic material content will increase, thus raising its economic value.
Biota recovery  100  Decreasing use of agrochemicals will improve natural ecosystems, water quality and flourishing of natural biota.
Carbon credits  88  The application of Azolla in rice cultivation can be incorporated into carbon credit markets decreasing contributions to global warming.


Building on its success, the project has developed partnerships and mobilized additional sources of direct and in-kind funding from public and private sources, mainly local and central government, of an additional $545,000. I am very excited about the potential for scale-up of this project, and the consequent change in paradigm for agriculture in Ecuador.

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