Biofertilizer
Microorganism
Nitrogen Fixers
Azolla pinnata, Rhizobium spp., Azotobacter chroococcum, Azospirillum lipoferum, Acetobacter diazotrophicus, Derxia gummosa
Phosphate Solubilizers
Bacillus circulans, B. coagulans, Torulospora globasa, Pseudomonas fluorescens
(siderophore), Thiobacillus (SOM), Aspergillus niger (avirulent), Trichoderma sp.,
Paecilomyces sp.
Potash mobilizers
Bacillus spp., Pseudomonas spp.
Zinc mobilizers
Bacillus spp., Pseudomonas spp., Rhizobium spp.
Table 1. Various microorganisms identified with the capacity to act as biofertilzers (Source:
Bhattacharjee & Dey, 2014; Afr J. Micro. Res. 8: 2332-2342).
fertilizers and pesticides. In addition, it is considered that the provision of inorganic fertilizers (that is,
without an appropriate carbon
source) to crops only serve to supplement the plant, and not the microbes that sustain them. And so it
is a management tool that is, by
design, one-dimensional in nature,
although it is acknowledged that
regulation needs to be achieved on
a much wider dimensional scale.
Therefore, it is proposed that a
more balance and holistically sound
approach be adopted that will attain the desired effect of crop resilience and enhanced agro-ecosystem
functionality.
At this backdrop, a timely new
course is envisioned for the sustainable development of agriculture
globally; one that deviates sharply
from conventional production and
that intends on increasing soil fertility through better management of
nutrient flow in and amongst the
various components of an ecosys-
tem. This new paradigm takes into
account the complexity of interactions that derive from the ecosystem properties of agriculture and
aims to access the free ecological
services on offer, while simultaneously attempting to reduce the
heavy reliance on external inputs to
control individual system components. As a heightened awareness
reverberates through the larger
farming community of the fragility
of the system, it is noticeable that
more farmers are committing to
more viable environmentally friendly alternatives. This, by implication,
requires the need for ecological
management as efforts are stepped
up to understand and inevitably
manipulate the soil biological component to enhance the contribution
of beneficial microbes. Till fairly
recently very little credence has
been given to the myriad of roles of
microorganisms, despite its ubiquity
in soils (see Table 1). Thus, it is expected that tailoring amendments
and cultural practices that promote
beneficial soil microbes will emerge
as an increasingly important intervention to help boost agricultural
productivity more sustainably. Research studies that reflect the complexity of the interactions that underlie the application of essential
microorganisms in agriculture highlight the need for more holistic approaches to farming management
strategies.
Three groups of plant-beneficial
rhizomicrobes are conveniently distinguished: mychorrhizae, N2-fixing
and plant growth promoting rhizobacteria (PGPRs). These aforementioned rhizomicrobes, although recognized more prominently for their
roles in nutrient cycling and acquisition, may also be indispensable for
disease control. However, the microbial mechanisms that underpin
their effectiveness have yet to be
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