In two successive seasons, two field experiments were conducted at
Moshtohor Research Farm, Fac. of Agric., Moshtohor to study the influence of
inoculation with mixed cultures of rhizobial strains and Azospirillum lipoferum
on growth, nodulation, yield and mineral composition of guar (Cyamopsis
tetragonoloba L.) on a clay soil. Two rhizobial strains (ARC802 and local
strain) were used singly and in combination with A. lipoferum.
The results showed that, all inoculation treatments had significant effect
in increasing the vegetative growth, nodulation, yield and NPK content of guar
plants more than control treatments. Inoculation of guar with individual
Rhizobium (especially ARC802) increased nitrogenase activity than individual
Azospirillum or combination of Azospirillum with Rhizobium.
Addition of Azospirillum in combination with Rhizobium (especially
ARC802) under the low rate of nitrogen fertilization was superior in increasing
Co2 evolution, nodulation, plant growth, yield and yield components of guar
plants. It seemed that, a positive response was found between Azospirillum and
Rhizobium depending on the Rhizobium species.