AMNA NAWAZ: As India takes on the title of the world's most populous nation, one question that looms ever larger thanks to climate change is how to feed 1.4 billion people.

Small-scale farming families, who account for the majority of India's people, complain of crops withering under record high temperatures, cycles of drought and extreme rainfall, and pest infestations.

Fred de Sam Lazaro has our report from Southern India.

It's produced in partnership with the Pulitzer Center and part of Fred's series Agents for Change.

FRED DE SAM LAZARO: The consultation is usually brief, with a quick diagnosis.

WOMAN (through translator): When they get big, they infest the field.

FRED DE SAM LAZARO: And prescription for a new insecticide spray.

WOMAN (through translator): So two milliliters in each liter of water.

FRED DE SAM LAZARO: This plant clinic is one of several so-called village knowledge centers set up by the nonprofit M.S.

Swaminathan Research Foundation to help farmers cope with myriad challenges, especially those brought on by the changing climate here.

KUPPUSAMY SUBRAMANIYAN, Farmer (through translator): Before, we used to have pests, but now the quantity or number we have to deal with is much higher.

FRED DE SAM LAZARO: Like most small scale family farmers, K. Subramaniyan doesn't have irrigation systems, relies entirely on rainfall, and must deal with increasingly unpredictable weather conditions.

KUPPUSAMY SUBRAMANIYAN (through translator): Ten years ago, we had clear seasons, rain in the rainy season.

We could plant when the sun was out.

Now rain has become very erratic.

There's too much rain.

Sometimes, there's no rain.

Sometimes, it even rains during the harvest, and that causes more losses.

FRED DE SAM LAZARO: It's been unseasonably hot in March and April, which he worries will add stress on the crop.

But to protect his burdened paddy fields from pests, it's ringed with rows of unrelated species like lentils to repel bugs, an approach he learned after consulting with the Swaminathan Foundation, where veteran scientist G.N.

Hariharan is a leader.

G.N.

HARIHARAN, Executive Director, M.S.

Swaminathan Research Foundation: It is a two-way process.

So, by listening to them or sitting with them, we can understand what exactly the issues are.

FRED DE SAM LAZARO: The goal, he says, is to help farmers adopt sustainable practices and to develop hardier crops, one example, cultivating more saline-tolerant species of rice, a key staple crop in a country with 4,600 miles of coastline.

G.N.

HARIHARAN: When sea level is increasing, most of our production system along the coastline are going to get inundated with seawater.

And, after that, the area will be salinized, and our normal crops cannot be grown.

DR. SOUMYA SWAMINATHAN, Chair, M.S.

Swaminathan Research Foundation: The foundation has focused on resilience and adaptation.

We know that, already, there are changes which cannot be reversed.

And, therefore, there has to be adaptation.

FRED DE SAM LAZARO: Dr. Soumya Swaminathan is a pediatrician and, until recently, the World Health Organization's chief scientist during the pandemic.

She now chairs the foundation named after her father.

DR. SOUMYA SWAMINATHAN: The whole aim was to really take science to societies.

FRED DE SAM LAZARO: Nearly 60 years ago, M.S.

Swaminathan used science to launch India's so-called Green Revolution.

It transformed India into one of the world's leading producers of major crops, like wheat and rice.

However, the widespread use, most experts say overuse, of synthetic fertilizers and pesticides has degraded soil quality.

That's pushed farmers to use even more chemicals to sustain productivity and contain disease.

Climate change has further aggravated the problem.

Soumya Swaminathan says the challenge now is to bring a balanced approach to India's food production.

DR. SOUMYA SWAMINATHAN: Keeping in mind that you have to feed 1.4 billion people, so the changes cannot be done in a way that compromises food production and the self-sufficiency that we have today.

FRED DE SAM LAZARO: The foundation's approach is to get critical information to farmers, sending audio messages with meteorological data to help inform what crops or seed varieties to plant and the best time to plant and how to diversify crops for income and improved nutrition, adding protein and vegetables.

DR. SOUMYA SWAMINATHAN: Today, we -- everyone has a mobile phone in their hands.

We have artificial intelligence, for example, that offers a lot of potential.

How do we see that those actually benefit, particularly the most small and marginalized farmers.

FRED DE SAM LAZARO: Arjunan Jayaraman says he has benefited.

He grows okra alongside the family's rice fields, and for years tried to control pests with chemical products.

Today, he has an organic approach.

The crop is robust, protected, it turns out, by marigolds and sunflowers, flowers that take the brunt of a pest that attacks the okra.

And Jayaraman now has his own beehives.

ARJUNAN JAYARAMAN, Farmer (through translator): When I was using inorganic methods of farming, the honeybee population declined because we used more pesticides.

FRED DE SAM LAZARO: Experts say the key challenge is to adapt and scale such models across a vast nation with varied landscapes, soils, social mores, and unpredictable weather.

ABHISHEK JAIN, Council on Energy, Environment and Water: It is a real day-to-day concern.

FRED DE SAM LAZARO: Abhishek Jain is with the Delhi-based Council on Energy, Environment and Water.

ABHISHEK JAIN: Almost eight in 10 Indians are living in districts which are going to be climate-vulnerable.

Areas which were traditionally flood-prone are becoming drought-prone, and areas which were traditionally drought-prone and becoming flood-prone.

So, almost 40 percent of India's districts are showing this swapping trend.

FRED DE SAM LAZARO: Exacerbating the challenges for the agriculture sector, a lack of workers.

To create employment for India's growing youthful population, the government has emphasized manufacturing, trying to lure multinational companies to build their factories in India.

That's likely to accelerate the urbanization of this country, with profound impacts on rural agricultural communities.

Arjunan Jayaraman says, farming is becoming increasingly lonely and devalued today.

ARJUNAN JAYARAMAN (through translator): We used to have plenty of people to work, because, in the home, the mother, the father, the child, all the siblings, they worked in the field.

But, today, they're going outside, working in companies.

Dr. Swaminathan says rural prosperity will be critical to India's future food security.

DR. SOUMYA SWAMINATHAN: Young people growing up in rural areas, perhaps in agricultural families, they need to see hope in pursuing an agricultural profession, but, at the same time, they also have a good physical and mental quality of life.

FRED DE SAM LAZARO: That will require agriculture-based industries like food processing, which in turn require hefty investment in better infrastructure, storage facilities, roads and schools in rural areas.

And in a rapidly urbanizing country, Jayaraman says, he hopes people become more aware of where its food comes from, returning the traditional reverence he was raised with for farmwork.

He cites a Tamil proverb: If you don't have mud on your feet, you won't see food on your plate.

For the "PBS NewsHour" I'm Fred de Sam Lazaro in Puducherry, India.

AMNA NAWAZ: And a reminder Fred's reporting is a partnership with the Under-Told Stories Project at the University of St. Thomas in Minnesota.