Microorganism Diversity, Importance & Applications in Agriculture: Biofertilizers & Challenges

Microorganisms are living organisms. They are smaller in size, and we have to observe them through microscopes. Different microorganisms are available all around us.

Microorganisms show different characteristics like size, shape, colour, habitat, etc. These differences make huge biodiversity among different microorganism species.

Microorganisms include

• Bacteria
• Fungi
• Algae
• Protozoa
• Viroid
• Prions.

The virus is also classified under microorganisms even though they are considered non-living organisms.

This section will discuss the

• Importance of microorganisms
• Applications of microorganisms in the field of agriculture

-Biofertilizers

• Experimental biofertilizer for Maize
• Challenges associated with biofertilizer application

What is the Importance of Microorganisms

Microorganisms can be both useful and harmful to other organisms including humans. Microorganisms are important to maintain ecosystem balance. Interestingly, microorganisms which host in human cells are important to

• Proper digestion of food
• Produce Vitamins including Vitamin K
• Developing immune system
• Detoxification of toxic compounds

Making use of microorganisms in different fields can be defined as biotechnology. These different fields include agriculture, medicine, the food industry, cosmetics, biofuel and environmental management.

These microorganisms are like chemical factories producing vital products including enzymes, medicines, amino acids and food additives. These microbial activities have been used by people from ancient times, including fermentation processes.

Applications of Microorganisms in Agriculture

The field of agriculture provides the need for food for both human and animal consumption. With the growth of the world population, the need for large-scale crop production was essential.

Industrialization supported the enhancement of the amount of food production. But at the same time, this industrial revolution created harm to the environment.

Agricultural productivity needs light, water, and healthy soil as three essential natural resources. Microorganisms can be used to improve agricultural productivity in different ways.

The microorganisms in the soil make a community which is generally called a microbiome. Soil microbes are important in decomposing organic matter, which provides nutrients by degrading dead organic matter. These soil microbes include bacteria and fungi. In addition to that, there are many uses for microbiomes.

The scientists understood the value of the functions of these microorganisms and the possibility of incorporating them in the field of agricultural improvements. An immediate need of bringing this functional potential of the plant-associated microbiome and its innovation into crop production was seen within the scientific community.

There is an associated complex microbiome with plants. They are with the capability of promoting plant growth, tolerating stress, supporting plant nutrition and antagonizing plant pathogens.

The microbes in the soil can improve agricultural productivity. These naturally occurring microorganisms are used by people to manufacture biological products which have the ability to recycle nutrients. This is an eco-friendly action where we do not create harm to the surrounding environment. These biological products include biofertilizers, biopesticides and bioinsecticides.

Worldwide crop production has been challenged by the increase in global population and climate change.

In order to keep a sustainable solution to improve crop production with the above-mentioned challenges, the integration of beneficial plant-microbe and microbiome interaction can be used. They can be a solution for combating abiotic stress, pests and pathogens.

We have to either increase crop areas or enhance the crop yield from the same land, in order to fulfill the food demand. Therefore the use of microorganisms within the existing agricultural lands provides sustainable solutions for issues in the field of agriculture.

As we try to increase production on the same existing agricultural lands through crop improvement, there is no need to increase the arable surface. Plant Growth Promoting Bacteria (PGPB) or Rhizobacteria can be used in plant development by using direct or indirect mechanisms. The bacteria living on or inside the plant roots are responsible for this. On further classifications, some PGPBs are classified as biofertilizers and biocontrol agents or biopesticides.

There are different studies where 7 phylum and 95 genera of microorganisms have been documented who have been used as PGBR, with the benefits, challenges and future prospects of their use.

Biofertilizers

Biofertilizers are natural fertilizers. Living microbial inoculants are the main constituents of biofertilizers. These free-living microbes include algae, fungi, bacteria alone, or a combination. That particular microorganisms are with the capability of enhancing the availability of nutrients in the soil for plants.

These microorganisms can be

• Nitrogen fixers
• Phosphate solubilizers
• Cellulitis microorganisms
• Growth promoters.

The use of biofertilizers is important for smallholder farmers since it is relevant to their income. Then it reduces the amounts of synthetic fertilizers needed to apply. It is essential to fulfilling the growing demand for food. These are being used in different crops including wheat, rice, eggplant, cucumber, tea, coconut, coffee etc.

Experimental biofertilizer for Maize

As a recent development, Latin America has produced an experimental biofertilizer for Maize. It is based on the strains of Azospirillum sp. and Psuedomonas fluorecens.

Both greenhouse experiments and field experiments have been demonstrated to identify that this biofertilizer can increase

• The size of the roots
• The amount of crocket
• The amount of dry matter
• The yield of the crop.

This ability to enhance the availability of nutrients in the soil for plants is based on a specific ability. They can convert the unusable form of the nutritionally important components present in the soil, to the usable form. In this conversion, the following microbial activities are important.

• Phosphate solubilization
• Nitrogen fixation
• Excretion of plant growth hormones
• Biodegradation

The use of biofertilizers has further importance as they are eco-friendly, productive, easily accessible to marginal farmers and more efficient. This is a sustainable way.

Applications of biofertilizers can be different in seed treatment, seedling root dip, and main field application. Since there are both advantages and disadvantages, it is recommended to get precautions while using them.  

Even though plant-beneficial microorganisms are used in widespread commercial applications, there is a number of issues to be addressed.

Challenges associated with biofertilizer application

Even though the use of biofertilizers is a biological approach to reaching sustainable forms of agriculture, there are several challenges to be addressed in increasing agricultural yields. These challenges include the following facts.

• Biofertilizers lean towards being susceptible to both biotic and abiotic stress.
• They do not perform in the field as same as in the laboratory and greenhouse.
• The effectiveness of biofertilizers varies based on the diverse environmental conditions in which the crops are growing in, including diverse ranges of soil type, soil biodiversity, rainfall, temperature and crop variety.
• Compared with synthetic fertilizers, biofertilizers act slowly. Because these microorganisms need time to be colonized in the roots with increasing their number.

Just because for these reasons, farmers do not tend to use these biofertilizers. It is needed to get action to avoid these issues. It can be suggested to use potential isolates based on their performance under field conditions for particular species and environmental conditions.

There are some studies showing that foliar application of biofertilizers affects microbial biomass and enzyme activity in the soil and yield-related properties of different crop varieties including Maize and White Grains.