Climate Change Shrinking Soil Microbes, Threatening Fertility And Nutrition, Says Study

Kanpur: Climate change driven by global warming is pushing the microscopic world of soil organisms into crisis, with a sharp fall in their numbers beginning to hurt soil fertility and crop nutrition, officials said.

Tests conducted at Krishi Vigyan Kendras have found that the decline in beneficial microbes is weakening soil health, resulting in poorly nourished crops. Experts warn that consumption of such produce can contribute to malnutrition among people.

On average, one gram of healthy and fertile soil earlier contained more than five crore microorganisms. Recent tests show that this number has dropped to around one and a half crore, officials said.

Director of research at Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Dr Mahak Singh, said rising temperatures linked to global warming were reducing microbial populations. “Higher temperatures affect soil microbes. Their numbers also fall when organic manure is not used in fields. These microorganisms thrive the most when cow dung manure is applied,” he said.

The university operates 15 Krishi Vigyan Kendras where soil samples are tested for nutrients and microbial activity. Singh said organic matter in soil has declined the most. “About 50 years ago, organic matter content was around two percent. Now it has fallen to between 0.1 and 0.2 percent. Microorganisms depend on organic matter for nourishment. When organic content drops, microbial activity weakens, affecting the entire ecosystem and soil fertility,” he said.

Senior soil scientist at the university, Dr Khalil Khan, said microorganisms play a key role in keeping the soil fertility cycle active. “These organisms activate 18 essential nutrients in the soil. They sustain the fertility cycle and maintain the ecological balance of farmland,” he said.

Soil tests have shown a decline not only in microbes but also in other nutrients, officials said. Through Krishi Vigyan Kendras, farmers are being encouraged to increase the use of cow dung manure and other organic inputs. They are also being advised not to burn crop residue, but to allow it to decompose in fields and plough it back into the soil. The use of vermicompost and green manure is also being promoted to protect soil microorganisms and improve crop nutrition.

Experts said soil microbes recycle nutrients and decompose organic matter, making nitrogen, phosphorus, potassium and sulphur available for plant absorption. They also fix nitrogen in the soil. Fungal threads bind soil particles, creating porous soil that improves aeration and water retention. Microorganisms also protect plants from diseases and aid in biological treatment of harmful pathogens.

The main groups of soil microorganisms include bacteria, fungi, actinomycetes and protozoa, scientists said.