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Analysis Of Down To Earth Magazine: Microbes To Improve Crop Yield

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”GS 3: Biotechnology, Achievements of Indians in Science & Technology”

The current estimated demand for bio fertilisers in India is 18,500 tonnes per year, while production is 10,000 tonnes.
Soil contains several natural microbes that help plants absorb nutrients. These can be cultured and modified into bio-fertilisers. They increase the availability of nutrients and boost yield by 10-25 per cent.

Chemical-free organic farming improves soil fertility, but there are conflicting views about their impact on yield.
To overcome this and boost productivity, the agriculture sector can tap into microorganisms.
Scientific research shows constructive and cost-effective use of bacterial, fungal and algal microbes can also have positive results on crop yields.
Microbes can be used as bio-fertilisers, biostimulants and biopesticides, cultured in the laboratory.

They promote root growth and decompose organic matter.
They do this by helping fix atmospheric nitrogen in the soil and the root nodules of crops, and by producing hormones and antimetabolites.
They also scavenge and solubilise phosphates from soil layers and help in soil mineralisation.
There are three bacteria used as nitrogen-fixing bio-fertilisers. The most common is rhizobium, which works best with legume crops.
Azospirillum, on the other hand, is used with higher plants or cereals like sorghum, maize, millets and fodder grasses.
Another common soil bacterium is Azotobacter.
The species A chrococcum is widely present in Indian soil and grows using soil organic matter.

Blue-green algae such as Tolypothrix, Nostic, Schizothrix, Calothrix, Anoboenosois and Plectonema are also used as bio-fertilisers.
They are called rice organisms as they are found in these fields.

Some microbes being cultured as biofertilisers can also be used as biostimulants.
They are defined as products designed to enhance plant’s nutrition efficiency, improve tolerance to abiotic stress and boost crop quality.
They may have organic and chemical matter, or mixture of these and microbes. Microbial biostimulants can consist of a single or multiple species of azotobacter, rhizobium and azospirillum bacteria, and even of Mycorrhizal fungi.

The development and use of biostimulants through the years has shown that some can have negative impacts.
So, countries like India and those in the EU have developed lists of “positive” and “negative” microbial biostimulants.
In India, the lists are made by the Central Insecticide Board and Registration Committee (CIBRC) and the Directorate of Plant Protection, Quarantine & Storage (DPPQS).

India is not only among the world’s largest consumers of pesticides but also ranks 12th in their production. Their demand is also rising.
According to a 2017 report by the Centre’s Department of Agriculture Cooperation and Farmers Welfare, consumption of biopesticides increased from 219 tonnes in 1996-97 to 683 tonnes in 2000-01 and to around 3,000 tonnes in 2015-16.
In 2016, the market was $70.45 million, growing at a compounded annual rate of 17.08 per cent.

Biopesticide research is at an early stage but evolving.
Investment in fermentation technology, improved delivery systems and promotion of biological control will help.
While the agriculture sector has found multiple uses for microbes, their promotion is hindered as they show varying effects in different climate and soil conditions.
Researchers in recent years have made synthetic communities of beneficial microbes to improve yields.
We can explore strategies to select synthetic inoculants that are better suited to different conditions.
In addition, existing national schemes to promote organic and natural farming can also include measures to boost use of microbial inoculants.