Saeideh  Ansari, Bahman  Khoshru, Mohammad  Reza Sarikhani, Amir  Nobahar, 
    Characterization and Quality Assessment of Four Common Commercial Biofertilizers in Iran,
    Agricultural Journal,
    Volume 16,Issue 1,
    2021,
    Pages 1-8,
    ISSN 1816-9155,
    aj.2021.1.8,
    (https://makhillpublications.co/view-article.php?doi=aj.2021.1.8)
    Abstract: The beneficial effects of biofertilizers in
agriculture rely on the quality of these biological
products, hence, qualitative control of biofertilizer is a
necessary process. Therefore, in this study, four common
biofertilizers (including Barvar2, biosuperphosphate,
Supernitroplus and Nitroxin) that are produced in Iran
were used to assess the qualitative criteria such as
bacterial populations, genus and strains identity
confirmation and also the determination of some Plant
Growth-Promoting (PGP) characteristics in each
biofertilizer. Finally, the effect of these biofertilizers
inoculation on maize (variety Single Cross 704) carried
out under the greenhouse experiment. Bacterial
enumeration showed that bacterial viable cell in
the Supernitroplus and Barvar2 biofertilizers was
(10<sup>8</sup> cfu mL<sup>&#150;1</sup>) and in the Nitroxin and Biosuper
phosphate was 10<sup>7</sup> and 10<sup>6</sup> cfu mL<sup>&#150;1</sup>, respectively.
Besides, the most solubilized P from tricalcium phosphate
source related to biosuperphosphate and Barvar2 with
close values to 400 and 350 mg L<sup>&#150;1</sup>. Nitroxin and Barvar2
had great potential in auxin production. N3, N5, Bio3,
SN2 and SN1 isolates produce siderophore in qualitative
(orange halo zone) experiments. The potassium releasing
from mica minerals by these four type didn&#146;t significant
effect and results of the production, showed Barvar 2 and
Nitroxin had the highest amount. Overall, 13 isolates were
obtained from biofertilizers and molecular
identification results showed that these isolates
belonged to <i>Pseudomonas</i>, <i>Bacillus</i>, <i>Pantoea</i>,
<i>Acinetobacter</i> and <i>Citrobacter genera</i>. Results from
the identifications revealed that two strains of the N3
and Bio2 are related to the <i>Citrobacter</i> and
<i>Acinetobacter</i> genus, reflecting the lack of proper
identification by producers. The result of the
greenhouse experiment showed the effect of
biofertilizers on chlorophyll index, N and K shoot uptake
was significant (&#945;&le;0.05). Both Barvar2 and
biosuperphosphate have increased N uptake in plant shoot
where as super nitroplus and biosuperphosphate had
maximum attribute in K uptake. None of the biofertilizers
had no significant effect on the chlorophyll index.
    Keywords: enumeration;PGP properties;quality control;Biofertilizer;molecular identification