Inoculum Production of Nitrogen Fixers | Biotechnology

For the preparation of this inoculant there are several criteria to be followed, e.g. strain selections. For Rhizobium, strains that are com­patible and produce effective nodules should be selected. Individual legumes have specific strains and hence it is difficult to prepare in­oculum with all strains since one strain is likely to dominate over the others. Hence wide spec­trum of strains of the cowpeamiscelleny is se­lected.

Principle:

Rhizobium and Azotobacter are grown on their respective media and transferred to carriers, and packed in order that they remain viable for several months.

Requirements:

1. Cultures of Rhizobium and Azotobacter.

2. Carrier like powdered peat, soil, lignite, powdered farm yard manure, etc.

3. CaC0₃.

4. Polythene bags.

5. Seeds.

6. Trays.

Procedure:

1. Neutralize the carrier (powdered peat, etc.) with CaC0₃ and autoclave.

2. Mix broth cultures of Rhizobium and or Azotobacter which should have 10⁹cells/ ml.

3. Cure the mixture in trays for two to five days in order to have a moisture con­tent of 35-40% on a wet basis. Result­ing product should have 3×10⁸ (300 million) cells per gram of peat.

4. Pack this in polythene bags where the population increases.

5. Make a slurry of the carrier based cul­ture with minimum amount of water and inoculate seeds by mixing with the slurry.

6. Dry seeds in shade and sow. For trans­planted crops, root systems of seedlings are dipped with slurry for 10-30 min­utes and planted immediately.