13 Plant Growth-Promoting Bacteria …
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growth hormones, antibacterial and antifungal metabolites, induce systemic resistance against many diseases and thereby ensure higher crop production and another
advantage of these microbes is that they can be applied with other biological inputs.
13.1.1 Organic Manures: An Alternative Source of Plant
Nutrients
Generally, plant and animal residues or by-products come under this category such as
compost, manure, and animal residues. Being organic, these fertilizers have a good
amount of different nutrients and therefore increase soil fertility (Li et al. 2018).
Unlike inorganic chemicals, these fertilizers do not show any harmful effects on
plants or human beings. Also, they are biodegradable, renewable, and sustainable.
However, beneficial microorganisms help in the adequate release of nutrients in
the soil from these fertilizers. Their strategic use may not only enhance the crop
production but also improves the soil quality and fertility.
Organic manures viz., FYM, vermicompost, poultry compost, cattle dung, etc.,
improve the physical properties of soil (water hold-ing capacity, soil aeration, soil
aggregation, etc.), prevent soil degradation and increase the population of beneficial
soil microorganisms. These organic amendments contain most of the nutrients in a
plant-available form such as nitrates, phosphates, exchangeable calcium, zinc, and
soluble potassium (Orozco et al. 1996). Similarly, forest litter also plays a fundamental role in nutrient turnover and the transfer of energy between plants and soil.
This is also a good source of the nutrients that are accumulated in the upper layers
of the soil. FYM is used in between 10 and 30 t ha
−1 in different crops including
cereals, pulses, vegetables, etc. Vermicompost and Forest litter are used 6–10 t ha
−1 .
However, the rate of application of organic manures can be reduced if applied along
with microbial inoculants biofertilizers. Several reports suggest a 25–50% reduction in organic manure requirements if beneficial microbes are combined with them
(Yildrim et al. 2011; Singh et al. 2015; Rahman et al. 2018).
13.2 Plant Growth-Promoting Bacteria
Although, much has been said about PGP bacteria (Maheshwari 2011; Maheshwari et al. 2015, 2017) it is pertinent to give a brief description about their
role and efficacy. Plant growth-promoting rhizobacteria (PGPR) are the beneficial bacteria closely associated with plant rhizosphere and possess plant growthpromoting abilities (Kloepper and Schroth 1978). These are used to improve soil
fertility and crop productivity and also as biocontrol agents to reduce crop losses.
To commemorate their spectrum of action, they are designated with several terms
297
growth hormones, antibacterial and antifungal metabolites, induce systemic resistance against many diseases and thereby ensure higher crop production and another
advantage of these microbes is that they can be applied with other biological inputs.
13.1.1 Organic Manures: An Alternative Source of Plant
Nutrients
Generally, plant and animal residues or by-products come under this category such as
compost, manure, and animal residues. Being organic, these fertilizers have a good
amount of different nutrients and therefore increase soil fertility (Li et al. 2018).
Unlike inorganic chemicals, these fertilizers do not show any harmful effects on
plants or human beings. Also, they are biodegradable, renewable, and sustainable.
However, beneficial microorganisms help in the adequate release of nutrients in
the soil from these fertilizers. Their strategic use may not only enhance the crop
production but also improves the soil quality and fertility.
Organic manures viz., FYM, vermicompost, poultry compost, cattle dung, etc.,
improve the physical properties of soil (water hold-ing capacity, soil aeration, soil
aggregation, etc.), prevent soil degradation and increase the population of beneficial
soil microorganisms. These organic amendments contain most of the nutrients in a
plant-available form such as nitrates, phosphates, exchangeable calcium, zinc, and
soluble potassium (Orozco et al. 1996). Similarly, forest litter also plays a fundamental role in nutrient turnover and the transfer of energy between plants and soil.
This is also a good source of the nutrients that are accumulated in the upper layers
of the soil. FYM is used in between 10 and 30 t ha
−1 in different crops including
cereals, pulses, vegetables, etc. Vermicompost and Forest litter are used 6–10 t ha
−1 .
However, the rate of application of organic manures can be reduced if applied along
with microbial inoculants biofertilizers. Several reports suggest a 25–50% reduction in organic manure requirements if beneficial microbes are combined with them
(Yildrim et al. 2011; Singh et al. 2015; Rahman et al. 2018).
13.2 Plant Growth-Promoting Bacteria
Although, much has been said about PGP bacteria (Maheshwari 2011; Maheshwari et al. 2015, 2017) it is pertinent to give a brief description about their
role and efficacy. Plant growth-promoting rhizobacteria (PGPR) are the beneficial bacteria closely associated with plant rhizosphere and possess plant growthpromoting abilities (Kloepper and Schroth 1978). These are used to improve soil
fertility and crop productivity and also as biocontrol agents to reduce crop losses.
To commemorate their spectrum of action, they are designated with several terms