The Soviet Union announced today that it would grant Poland major new credits on easy terms to secure continued flow of Soviet energy and raw materials to the beleaguered military government of Premier Wojciech Jaruzelski.

The credit was reported to be worth $3.4 billion, and it appeared to cover part of Poland's 1981 trade deficit as well as the anticipated deficit this year. Polish sources here said the figure did not include Soviet hard-currency credits extended to Poland, apparently designed to help the Poles meet interest payments due on their huge debt to Western banks.

The new credits were part of a wider agreement that included a Soviet pledge to supply Poland with food, energy supplies and raw materials. The package demonstrated Moscow's recognition of the economic costs of reversing the reform movement in Poland--and its willingness to pay that price.

There have been numerous reports in the Polish and Soviet press recently about shipments of fuel and food from the Soviet Union to the Poles, all coming amid signs of a tight food situation within the Soviet Union itself and reported cutbacks in Soviet energy supplies to other East European countries. The new agreement with Poland appears to extend this situation through 1982.

Announcing the agreement, the government news agency Tass said merely that "taking into account the difficult situation in Poland's national economy, the Soviet government agreed to grant [Poland] an easy-term credit to repay the difference in the values of mutually delivered goods."

The trade protocol was signed today by the Polish foreign trade minister, Tadeusz Nestorowicz, and Soviet Foreign Trade Minister Nikolai Patolichev.

Tass said the Soviet Union would continue to deliver oil, natural gas and other raw materials to Poland in 1982. Poland is expected to deliver machine tools, construction machinery, equipment for the chemical industry and farm machinery to the Soviet Union. The agency made no mention of Polish coal deliveries, which have fallen sharply during the past year.

Nor did Tass publish any figures about substantial financial assistance in hard currency to Poland or mention the emergency food deliveries.

Nestorowicz, who arrived earlier today with a large delegation, was expected to conduct talks Thursday with Deputy Premier Nikolai Baibakov, the chairman of the Soviet State Planning Commission.

Poland is Moscow's second-largest trading partner with their overall trade for 1980 amounting to $11.3 billion, compared with $13 billion between the Soviet Union and East Germany. The largest Western trading partner of Moscow is West Germany, with total trade in 1980 amounting to $8.3 billion.

During the past year of turmoil in Poland, bilateral trade has dropped sharply. Official Soviet figures indicate that the Poles had cut scheduled deliveries to the Soviet Union by roughly 50 percent.

At the same time, the Kremlin not only has kept its deliveries to Poland on schedule but also has increased them considerably.

The Soviet Union had announced earlier that Poland could defer repayments on its debt for the next four years to help the country cope with its severe economic and political problems.

Soviet food assistance is believed to be in the form of outright grants while Soviet hard-currency credits to the Poles during the last year are variously estimated to be between $1 billion and $2 billion.

According to official Soviet figures, exports to Poland for the first six months of last year totaled $3.4 billion while Polish exports to the Soviet Union were $2.3 billion. The imbalance is believed to have deepened during the second half of 1981.

The size of the Polish debt to the Soviet Union has never been disclosed. But it is clear from the new protocol that it will grow in 1982.

The total trade for 1982 envisioned by the agreement would amount to $12.6 billion, of which $7.2 billion would be Poland's purchases from the Soviet Union while $5.4 billion would be Polish exports to the Soviet Union.

A Radio Warsaw broadcast said that because of Poland's current economic difficulties the country would have to depend solely on Moscow this year for key imports including oil, natural gas, iron and timber.

The Soviet readiness to send these commodities for which Poland is unable to pay was described by the Warsaw broadcast as an "expression of understanding for our country's economic situation and an example of fraternal aid."

Last year, the Soviets increased by 2 million tons to 16 million tons their oil deliveries to Poland. At the same time, they cut by 10 percent their oil deliveries to other East European countries. The East Europeans buy Soviet oil at 50 percent of the OPEC price.

Tass gave no figures about the specific Soviet deliveries to Poland. But it is clear that the Polish crisis has put an additional strain on the Soviet economy while causing economic disruptions here due to Poland's failure to meet its scheduled obligations.