Azospirillum is a genus of plant growth promoting bacteria (PGPBs), which have been widely studied over the past few decades. In addition to fixing atmospheric nitrogen, Azospirillum inoculation also provides plants with phytohormones such as indole-3-acetic acid, which are essential for the growth of plants.

Azospirillum results in the following benefits

1. Promotion of root hair development and branching;
2. Increased uptake of N, P, K and microelements;
3. Improved water status of plants and,
4. Increased dry matter accumulation and grain yield
Azospirillum fixes nitrogen from 10 to 40 kg/ha. They are found to colonize the root system of many vegetable plants. Azospirillum inoculation helps the plants in better vegetative growth and also in saving input of nitrogenous fertilizers by 10%–20%

The N source used by Azospirillum

The N source used by Azospirillum for their growth:
- Ammonium
- Nitrate
- Amino acids
- Elemental N