Agriculture Reference
In-Depth Information
1.5.7.1 Seed Treatment
Coating/bacterization of plant seeds by microbial cultures involving microphos has
traditionally been the most common and widely used method in agricultural
practices for enhancing crop production across different ecological niches (Khan
et al. 2007,
2010
). In this method, one packet containing 200 g of microphos is
sufficient to treat 10 kg of healthy and good quality medium-sized seeds of
groundnut, wheat, cotton, maize, etc., whereas 100 g per acre inoculant is required
for priming small-sized seeds. For seed treatment, one packet of the microphos is
cut open and the inoculants (bacteria-carrier mixture) are mixed with water to make
slurry and then mixed with seeds. To achieve the firm and sufficient coating of
inoculant on seed surface, use of adhesive/sticker solution such as 10 % gum arabic,
methylethylcellulose, sucrose solutions and vegetable oils is recommended.
Furthermore, any locally available sticky material (e.g. jaggery solution) which is
non-toxic to bacteria and seeds can also be used as adhesive. The seeds intended for
one-acre lands are then dipped in the slurry for about 3 h so as to have a uniform
coating of the culture over the seeds. The uniformly bio-primed seeds are then dried
under shade for 30 min, and the shade-dried seeds are sown in pot or field soils
within 24 h. Even though this method allows the adequate loading of bacterial cells
on to the seeds [10
8
cells/seed], this method has certain limitations, for example, the
bacterized seeds may come in direct contact with any seed applied with chemicals,
which, in turn, may adversely affect the survivability of the inoculated strains.
Secondly, the bacterial cultures after application may move away from rooting
zones and hence could be exposed to agrochemicals after planting.
1.5.7.2 Seedling Root Dip
Here, contents of the microphos packets are mixed in water, and the root portion of
the seedlings required for an acre is dipped in the mixture for 5 to 10 min; seedlings
are then removed from the suspension and transplanted as early as possible.
Suspension of one kg microphos in 10-15 l of water is sufficient for treating
seedlings for one acre. This method is generally used for transplanted crops,
for instance, vegetable crops.
1.5.7.3 Main Field/Soil Application
Seed inoculation technique in agricultural practices may not always be successful.
For example, if PS organisms belonging to N
2
fixing (e.g. rhizobia) are applied, it
may result in poor nodulation and hence depressed nitrogen fixation by legumes.
Secondly, there may be low colonization and weak establishment of the inoculated
rhizobacterial strains. This situation might be due to low population and/or low
survival of the inoculated bacterial strain on the seed surface and in the soil.
