Finding ways to farm the Amazon - and save it. Brazil is pushing ahead to develop the riches of the rain forest and open its territory to landless peasants. Ecologists, turning from the fight for total preservation, are coming up with new ideas for minimizing the destruction.

Six months ago, Jos'e de Oliviera came to this settlement in Rond^onia State with a pocket of change and title to 125 acres of tropical rain forest that the government had given him. Needing to plant crops that could quickly provide him with food and a bit of cash, the 29-year-old immigrant promptly cut and burned four acres to plant rice, beans, and manioc.

In two or three years, however, he will have to abandon these plots because the fragile soil will have been leached of its crop-producing nutrients. Mr. de Oliviera will then have to chop down another parcel of rain forest to plant more crops.

Hundreds of thousands of immigrants to Brazil's Amazon region have repeated this process in the last few years. They arrive, often with little more than the shirt on their back, and immediately clear a small plot of rain forest to plant crops that will quickly provide sustenance. And when the soil is depleted, they raze another patch.

Scientists say that this slash-and-burn cycle has contributed greatly to the steady destruction of the Amazon. And they say it must be halted if the rain forest is to be preserved.

To achieve this goal, they have designed plans in recent years to slow the devastation by allowing immigrants to plant crops that would provide a stable, long-term income on a single plot. They call for the Brazilian government and multilateral agencies that lend to it for the Amazon basin's development to put these plans into action.

``There's been a real change in ecologists' thinking in the past few years,'' says Anthony Anderon, chief of the botany division at the Emilio Goeldi Museum in Bel'em and the sponsor in January of the first conference to analyze alternatives to deforestation.

``Previously, we just wanted the Amazon to be set aside. But with the government confronted with not being able to leave the rain forest intact, we've begun focusing on ways to rationally use the already-occupied forest,'' Mr. Anderon explains.

Government officials view the development of the Amazon as beneficial. They see it as an outlet for settling poor, landless peasants, gaining extra revenue from minerals, and creating jobs.

Scientists agree that to reduce devastation of the rain forest, settlers must have the use of public credit, technical assistance, health care, and equipment. They disagree on whether the government or the settlers should manage the funds.

Jim Lafleur, a consultant to the Rond^onia State government, says that because immigrant farmers receive no aid, they have no choice but to adopt the slash-and-burn clearing techniques that are steadily destroying the rain forest.

``The immigrant is undercapitalized so he has to provide something quick - he can't wait for crops ... that take four or five years,'' Mr. Lafleur says. He is ``forced to be like an army ant and cut down the forest as he goes in order to survive.''

To break this cycle, Lafleur says the government must provide technical know-how and equipment so the farmers can plant crops that provide higher incomes on one piece of land for years. These so-called perennial crops include coffee, cacao, black pepper, and Brazil nuts.

The government should also provide loans to farmers to tide them over during the three years before the perennial crops' first harvest, Lafleur says.

Under this scheme, farmers would initially clear a larger area - perhaps 30 acres - but over 20 years they would devastate much less rain forest. They would at first plant both subsistence and perennial crops on about four acres.

Then they would rotate the subsistence crops yearly among the other 26 acres while maintaining the perennial crops on one plot of land for 10 years (when the soil goes bad for such crops). With both the rotation system for the subsistence crops and a steady income from the perennials, farmers would not need to fell more forest.

``We need permanent farmers who can sustain themselves on a constant unit of land,'' Lafleur says. The higher income and greater stability perennial crops provide would discourage farmers from the common practice of selling land to cattle ranchers who raze swatches of forest to create pastures. ``Currently, immigrants can make more money from selling the land than from farming it,'' Lafleur says.

The World Bank is negotiating a multimillion-dollar loan with Brazil's federal government that would implement this program - by increasing assistance to farmers on already-settled areas in Rond^onia.

But Wim Groenveld, a tropical scientist in Porto Velho, Rond^onia's capital, says that chronic government mismanagement and corruption will keep farmers from getting the money earmarked for them.

Mr. Groenveld charges that government and World Bank funds that were supposed to aid immigrants during the northwest region development program in the early 1980s disappeared or were misspent.

Instead of having the World Bank and other foreign donors give money to government agencies, Groenveld says, the institutions should offer funds directly to local farmers' unions and other grass-roots organizations.

Groeneveld says he would like to establish several pilot projects for these groups, which are just getting organized, to see how well local settlers can manage development aid. His project faces funding problems, though, because the World Bank, which is potentially the biggest donor, lends only to governments.

Increasing aid to settlers, while potentially the most significant proposal, isn't the only project being put forward to slow the Amazon's destruction.

Walter Bowen, an American agronomist in Manaus, is experimenting with ways to extend the period of time the Amazon Basin's delicate soil can produce yields before being depleted.

``I'm not sure how economic farming on Amazon land can be, but the correct use of lime and fertilizers could increase the length of time a plot of land provides yields from three years to five years,'' Bowen says. This improvement alone could reduce the devastation by 40 percent.

In another promising project, the federal government has created four ``extractive reserves'' for rubber tappers this year in Acre State. Under this designation, the government prohibits outsiders from devastating the forest areas where rubber tappers live and work.

Francisco ``Chico'' Mendes, the rubber tappers' leader, says ranchers have razed more than 1 million acres of land in Acre State and that the extractive reserves provide the best protection for the rubber tappers - and thus the rain forest itself.

On another front, the International Tropical Timber Organization, which represents both consumer and producer nations, created in June a $3 million program in Acre State to study ways the Amazon can be logged with the rain forest left intact.

Jos'e Carlos Carvalho, who heads the federal government's forest agency, has called for the creation of additional forest reserves where loggers could operate with government permits. He says that opening selected areas with government supervision to timber companies could prevent cattle ranchers from destroying these stretches of rain forest.

Groenveld says these proposals may not halt the inexorable devastation of the Amazon, but they offer the only hope. ``You can't stop the deforestation,'' he says. ``But you can minimize its negative impact and try to reduce the area being deforested.''