Cultivation and uses of Azolla in Egypt

Abstract

Azolla is a genus of small fern that is found in the temperate and subtropical regions. The ferns grow floating on the water surface and in rice fields. It is well known that Azolla grows rapidly and can double its weight in a nitrogen-free medium within 3–5 days.

Azolla ferns live in association with a blue-green alga Anabaena azolla which is located in cavities of the ferns’ lobes. The algae efficiently fix atmospheric nitrogen, and consequently improve the growth of the surrounding plants (Azolla and rice). Cultivation of this fern is considered to be a very cheap biofertilizer for rice fields. When the fern decomposes in soil, it supplies the cultivated plants with other minerals along with nitrogen; it contains fair amounts of phosphorus and potassium. In addition, it improves the soil texture, acting as an organic fertilizer.

Cultivation of Azolla in rice fields can substitute for 10 kg N/Feddan, which is about 50% of the recommended inorganic nitrogen fertilizer, with a 10% increase in the yield of rice. The vigorous growth of Azolla in rice fields suppresses the spread of weeds in such fields. Fayoum is one of the important provinces cultivating rice where Azolla can be grown economically as an intercrop with rice.

Azolla technology in the rice fields of Fayoum was transferred to the appropriate provinces of Fayoum through a Technology Transfer Grant. Training courses and workshops have been conducted to assist in the transfer of the technology of utilizing Azolla as a fertilizer.

For field multiplication and distribution of Azolla, more than 20 nurseries (Cement or Plastic) were established in the rice-producing areas in Fayoum, gaining great popularity among the farmers. Based on proven methods and results, farmers have been taught how to use Azolla as green manure in rice field production, including its nursery culture, multiplication, management and utilization as organic fertilizer for rice, other field crops and vegetables.

The field experiments at Fayoum proved that incorporation of Azolla in rice fields increased the yield by about 8%, saved 50% of nitrogen chemical fertilization costs and produced high purity of rice, up to 99%.