Azospirillum is a free living symbiotic nitrogen fixing bacteria. It grows around the roots of non-leguminous plants such as cereals, millets, oilseeds, cotton etc. It is capable of absorbing atmospheric nitrogen and converting it into a form that can be utilised by plants.
Azospirillum is suitable for both upland and wetland conditions.It works effectively in those soils where the phosphorus content is less.
It produces plant growth hormones in the root region thereby increases plant growthand yield.It fixes about 20-25 kg nitrogenper ha under ideal conditions.25-30 per cent of the nitrogen fertilizers can be saved by the use of azospirillum.
Commercially it is available as carrier based inoculum.The recommended method of application includes seed treatment, seedling dip and direct soil application along with organic manure.
Take 500gram culture in a plastic tray/basin. Moisten it by sprinkling water or rice-gruel water (500 ml). Add moistened seeds, mix well and dry under shade for 30 minutes. The treated seed should be sown immediately.
For seedling dip the slurry of the culture may be prepared by mixing 500g culture with 2.5 litre of water. The roots of the seedlings for transplanting are dipped in the slurry for 15-20 minutes before transplanting.
For soil application one kilogram of the culture is mixed with 25 kilogram of FYM or compost and applied directly in the soil.For crop of six-month duration, the recommended dose is 1-2 kg/ha. This can be increased to 2-4 kg/ha for crops having more than six months duration.
For perennial crops, 10 to 25 gram of the bio fertilizer may be applied in the root zone during the first year and 25 to 50 gram during subsequent years. This can be done at the time of sowing, transplanting or during intercultivation.