Effect of Seasonal Variation on Growth and Nutritive Value of Azolla pinnata under Agro Climatic Condition of Assam

Background: Azolla is a free floating aquatic fern fixes atmospheric nitrogen in association with nitrogen fixing blue green algae. There have been some studies about the differences in temperature, rainfall and humidity influence on Azolla production. Hence, the present experiment was undertaken to study the effect of seasonal variation on growth and nutritive value of Azolla under the agro climatic condition of Assam. Methods: Azolla beds were used to cultivate Azolla pinnata with three replications and the size of the individual beds were (10×4) m. Deep bore well was the source of water for growing with pH 5.8. The fresh Azolla pinnata was collected from the nearby pond of the farm and further cultured. The meteorological data were collected everyday and production data were collected fortnightly. Two samples of fresh Azolla pinnata were collected and analysed for its nutritive value during the month of January and June 2021 in order to evaluate the difference of nutritive value due to seasonal variation. Result: Highest fresh Azolla was recorded in bed 2 (9.5 kg) in the month of May and lowest being recorded by the bed 2 (2.0 kg) during January. The increased Azolla production during May to June was attributed to the rise of temperature prevailed in the surrounding area of ZLRS, Mandira. There were no significant differences between the two seasons regarding the nutrient content of Azolla.