Relative nitrogen fixing efficiency of Azotobacter isolates and self life of different organic carriers.
Madan Kumar, Singh A. K.
Author Affiliation: Ramakrishna Mission Vivekananda University, Ranchi, Jharkhand, India.
Environment and Ecology 28 : 1655-1659
Abstract : This experiment was conducted in 2007-08 with 12 isolates of Azotobacter species isolated from' rhizosphere of different fruits trees of Ranchi and Gumla districts. It is well known that the carrier-based bionoculants are effective as carrier determines the shelf life of the Azotobacter. Hence the selection of better carrier is essential for maintaining shelf life of the Azotobacter during storage and for better performance in the field use. In present study, nitrogen efficiency of different local fruit isolates of Azotobacter was evaluated and studied the effect of vermicompost as carrier materials in the place of lignite. Among different isolates AZ 3 (14.0 mg N/g sucrose or 14.0 mg N/ml in culture medium) and AZB (13.49 mg N/g sucrose or 13.49 mg N/ml in culture medium) from rhizosphere of jack-fruit and guava,. respectively fixed significantly higher nitrogen than others. The survival capacity of Azotobacter isolates in sterilized vermicompost and vermicompost plus FYM carrier recorded maximum value of 32.70×108 cfu/g and 28×108 cfu/g of dry weight from 90 to 120 days and gradually declined to 3.07×108 and 0.50×108 cfu/g of dry weight on 240 day of storage, respectively.