In-vitro experiment of nitrogen fixing capacity of indigenous and exogeneous Azotobacter sp at Andisol tea planting area’s

Abstract

An in-vitro experiment to evaluate total nitrogen content of soil of tea plantation area included with indigenous and exogenous Azoto­bacter sp have been conducted in the Biology and Soil Biotechnology Laboratory, Padja­djaran University. A completely randomized design with 11 treatments and three repli­cations was used. The treatments were: A (ne­gative control); B (positive control); C (A. Kedelai II); D (A. vinelandii); E (A. N.D.9.3); F (A. Padi); G (VI-1); H (II-1); I (V-2); J (I-1); and K (III-2). Size of microbe inoculated popu­lation for each treatment was 1,2 x 1011 CFU/ml. One percent dose was used for ste­rilized soil originated from the tea plantation area. After five days of incubation period re­vealed that II-1 Azotobacter sp produced very significantly different in total nitrogen pro­duction than the other Azotobacter sp, i.e. 0,8532%. Orthogonal comparisons indicated that indigenous Azotobacter sp had the capacity of nitrogen fixation 7,67% higher than that the capacity of nitrogen fixation of exogenous Azotobacter sp for growth on Andisol soil of tea plantation area with pH of 4,5-5,6. Although, Azotobacter sp is very rarely found in soil with low pH (high acidity), this phenomena indi­cating that an active biofertilizer of indigenous Azotobacter sp is present in tea plantation area.