TITLE:
Biochar Based Inoculants Improve Soybean Growth and Nodulation
AUTHORS:
Martyna Głodowska, Timothy Schwinghamer, Barry Husk, Donald Smith
KEYWORDS:
Biochar, Bradyrhizobium japonicum, Glycine max, Inoculant Carrier, N-Fixation
JOURNAL NAME:
Agricultural Sciences,
Vol.8 No.9,
September
28,
2017
ABSTRACT: Most rhizobial inoculants that stimulate legume yield are applied with carriers
that enhance root contact. The physicochemical properties of biochar are
suitable for microbial growth, and it could be an alternative to peat, which
comes from decreasing reserves but is the commonest solid inoculant carrier.
The aim of the current research was to evaluate biochars as carriers of bradyrhizobia
in solid inoculant and as coatings for seeds. Biochars and peat were
inoculated with Bradyrhizobium japonicum strain 532C and storage time was
assessed. A seed coating system was developed using biochar, bacteria liquid
culture, water, and guar gum. The viability of bacteria in the coating and in
solid biochar was evaluated at 4°C and 21°C. Two biochars were selected for a
germination assay. Finally, greenhouse experimentation investigated the effect
of biochar inoculant and seed coating on soybean growth and nutrient uptake.
The storage time experiment showed that not all biochars equally sustain bacteria
survival over time. The germination assay demonstrated that biochar
seed coating had no effect on soybean germination. Greenhouse experimentation
indicated that the effect of Pyrovac biochar on soybean growth characteristics
and nutrient uptake depended on the fertilizer. The main finding was
that biochar solid inoculant positively affected plant growth metrics, root
characteristics, and the chemical composition of plants supplied with N-free
nutrient solution.