A highly ambitious plan to turn Sudan into a "breadbasket" of the Arab world is testing the strategy of combining Arab oil money with Western technology to help some of the Third World's poorest nations develop rapidly.

If the plan succeeds here, it could well became the basis for a whole new model of development, providing an alternative to the socialist model that now exercises a magnetic attraction on the increasing number of developing countries.

Moreover, the combination of conservative Arab wealth and Western know-how could prove an irrestible political force capable of swinging a number of African states back toward the West. Already, Sudan has been swayed away fron its former socialist path and close ties with the Soviet Union, and Marxist Somalia is currently being courted by Saudi Arabia with a promise of massive economic and military aid in return for the expulsion of the Soviets.

At this point it is still too early to judge the effectiveness of the strategy, but the initial prospects appears good, based on what is happening here in Sudan, the largest country in Africa. Sudan holds an enormous unrealize potential for food production.

Already, this country is posting a 4 perc ent to 5 per cent growth rate, while most other African countries are barely holding even or are slipping backward. The Arab goal is to boost this rate to 7.5 pert cent a year, making it an economic pace-setter on the continent.

Led by Saudi Arabia and Kuwait, the Arab countries have drawn up a $5.7 billion investment program for Sudan, and a growing number of Western companies are proferring goods, skills and technology, often in partnership with Arab interest.

Far more than Egypt, seemingly a bottomless pit for Arab petrodollars with a dim outlook for any returns, Sudan seems to have all the ingredients for becoming a long-term paying Arab investment.

Unlike Egypt, this country had millions of idle acres of rich land and no problem of overpopulation. Indeed, with only 17 million people scattered over nearly a million square miles of land, it is, if anything, too sparsely populated. In addition, Sudan has large quantities of water still available from the two Nile rivers, an excellent climate and a fair number of technicians and administrators.

But there are still many obstacles to a rapid economic take-off, including a small labor force, few good roads (only 200 miles of hardtop until recently), limited port facilities, an inadequate and an easy-going work ethic that has yet to adopt to the rigors of a would-be booming economy.

Last year there was a shortage of migrant laborers to pick cotton, the country's big foreign-exchange earner, and skilled and even unskilled workers are emigrating by the thousands to the nearby Arab oil states. Gasoline shortage are chronic, even in the capital, and the projects under way are meeting long delay and huge cost overruns.

Some of these problems are on their way to a solution. For instance, a 500-mile pipeline carrying 4.2 million barrels of oil from Port Sudan to Khartoum ia about to begin operating: the various piece of the 750-mile-long road from the coast to the capital are nearing completion and new locomotives are rolling stocks are increasing the railroad's capacity considerably.

For other problems such as manpower, no immediate solution is in sight. "There's a real movement of skills out of Khartoum to Jeddah" said one Western economist. "It's getting difficult even to find domestics because the salaries in Saudi Arabia are five to six times higher than here."

Undaunted by bottlenecks, the oil powers of the Arabian peninsula are becoming daily more committed to uplifting Sudan as part of their own long-term economic survival strategy, particularly in food production.

Saudi and Kuwaiti money in particular is pouring into Sudan by the tens of millions of dollars as projects are identified, studied and put into execution, usually by the consortium of the Arab and Western companies. No one seems to know precisely how much Arab and Western capital is now tied up or committed here, but one estimate put the total sum at well over $1 billion, with more coming all the time.

In addition, Saudi Arabia is thought to have provided something like $350 million in the past few years in various disguised forms to cover Sudan's chronic balance-of-payments deficit. Western economists do not expect Sudan to default on its short-term debts of somewhere around $500 million, because, as one of them put it, "the Saudis will bail them out."

The Arab commitment to Sudan's aconomic development is embodied in the about-to-be-established Arab Authority of Development and Agricultural Investment, which has been set up to implement the initial $5.7 billion, 10-year Arab investment program here.

This is part of the 25-year plan to make Sudan the primary source of food for the whole Arab world and to create an alternative source of investment to the industrial West for excess Arab petrodollars. Reading between the lines of the 56-page Arab proposal, one clearly detects the unstated objective of freeing the Arab world from any kind of blackmail by oil-consuming nations, such as the United States, that might attempt to use their food export as a bargaining chip against the oil producers.

By 1985, Sudan is projected to be providing 42 per centr of the Arab world's total vegetable oil consumption, 58 per cent of its basic food and 20 per cent of its sugar needs, according to the plan drawn up by the Arab Fund For Economic and Social Development.

Tho achieve this initial goal, the amount of land under irrigation in Sudan will have to be increased from about 3 million to 4.4 million acres and the rained crop area from 12 million to 17 million acres. Production of livestocks will have to jump 35 per cent from its present level, the plan states.

Of the $5.7 billion investment, the Arabs are apparently scheduled to provide $2.75 billion in hard currency and Sudan to raise the rest in local savings.

The authors of the ambitious plan raise the question of this country's ability to absord such a large infusion of outside capital and also to pay the principal and interest on loans expected to total $4.58 billion. But they conclude that this is not a sufficient argument against the plan even if its completion is delayed several years due to the existing bottlenecks.

The plan described at length the tremendous potential here for a massive expansion in agriculture. Only about 15 million acres have been put to use in this sprawling country, it says, while there are easily an additional 6 million acres available for irrigated land, 71 million for rainfed crops and 200 million for grazing land.

Everyone here seems to think in six-digit figures when planning new farming schemes and nine-digit price tags. For example, the new Rahad farm near Wad Madani, 110 miles soutneast of the capital, which is scheduled to begin production this year, will cover 300,000 acres and is costing between 250 million and $300 million.

The Kenana sugar estate near Rabak in the White Nile Province will produce 350,000 tons of sugar a year when it begins operation late next year. It is expected to cost more than $800 million before it is completed and to be one of Africa's largest.

Otherprojects under discussion to grow cotton, grain, peanuts and other export crops involve as much as 500,000 to 620,000 acres in a single development are are priced in the hundreds of millions of dollars.

American agribusiness representatives here are practically drooling over the prospects. "I have to say, it's a country that has tremendous potential for farming," say Wayne Richardson Jr., a top official of the Honolulu-based Alexander and Baldwin Co. who has worked here in 60 different countries here.

"It has more ingredients for good agribusiness than any other country in the world," he said enthusiastically. "The climate is great and there is a lot of land waiting to be irigated." But he added, "it's not a get-rich-quick kind of thing here. You have to think in terms of 10, 12 or 15 years and you'll need a lot of patience and understanding. But as you can see, I'm bullish on prospects but awareness of the need for a great deal of patience to deal the Sudan."