Prime Minister Indira Gandhi mobilized the resources of her ruling Congress-I Party today for a massive farmers' rally here designed to demonstrate that her government still has the support of rural India.

About 1 million farmers flooded this capital city to hear the prime minister caution them against pressing for more government aid at the expense of the rest of the country. The rally, in which the party used facilities of the central and state governments, appeared aimed at answering a wave of farmer unrest in south-central India late last year over demands for more government price supports and subsidies for fertilizer and diesel fuel used for tractors and irrigation pumps.

Observers here said the Congress-I, for Indira, rally was also organized to counter one planned for a month from today by opposition farmers who want to capitalize on the unrest in the country.

Despite the low-key nature of her speech and her refusal to make specific promises to the farmers, Gandhi won warm applause from the crowd that filled a large section of the open mall that lines Rajpath, an impressive road running among government buildings.

"We are for Indira Gandhi. Whenever she says the word, she will keep it in the long run," commented Meignana Moorthi, a land-owning farmer from the southern Indian state of Tamil Nadu who said he paid his own way to travel for 44 hours in a train to come to the rally.

Most of the farmers came from nearby northern Indian states where the Congess-I parties that control state as well as central government facilities arranged for 150 special trains and thousands of trucks and buses to carry people to New Delhi for the rally.

Many of the farmers received free chits for their transportation here as well as meal tickets while they were in New Delhi. Some were seen getting small amounts of cash. For many, it was a kind of holiday and one of the few times in their life they would be able to see their nation's capital.

"It's like a festival coming here," said Deep Chand Misra, one of a group of farmers from the state of Bihar who were sitting on the ground in their dhotis, the Indian loinclothlike garment that reaches below the knee.

Traditionally, Gandhi's Congress Party holds the support of India's farmers, who make up about 80 percent of the population. While the January 1980 election that returned Gandhi and her party to power showed that she still has firm support, recent demonstrations have indicated the possible beginnings of rural defections.

Gandhi's government and party went all out to make the rally a success. They set up 25 tent cities around the outskirts of New Delhi for farmers to spend the night, arranged food packets for them, hired scooter rickshaws with loudspeakers to whip up enthusiasm and established bus parking areas near the rally site.

Major central city streets were closed to traffic so the farmers could walk to the rally and televison sets were placed all around the area so farmers sitting far from the tall brick podium could see Gandhi, who looked resplendent in a white sari, on a special closed-circuit system.

In all, 16,000 police from neighboring states as well as New Delhi were here to keep order.

The massive influx of farmers disrupted life in New Delhi. Many people complained that they could not get to their offices for the crowds, schools were closed, three dry days in a row were declared to make sure the visitors did not get drunk and some trains were reported as much as 18 hours late because of the extra Delhi-bound rail traffic.

But the farmers lent color to New Delhi and provided a strong reminder that the heart of India remains the land, not its great cities. On Shanti Path, New Delhi's embassy row, throngs of Rajasthani farmers, their heads wrapped in bright turbans, provided a colorful contrast to the modern diplomatic missions they walked past.