COLUMBIA, S.C. (AP) _ South Carolina farmers will receive a big economic boost when Taiwan purchases nearly 109,000 metric tons of state-grown soybeans, corn and tobacco this month.

''I can see this as a real positive effect on the agricultural economy. It moves volume out of the state and out of warehouses,'' said state Agriculture Commissioner Les Tindal. ''We're striving to sell what we produce.''

The commodities contract, which will be worth nearly $30 million, will be signed Oct. 17 in the House chamber of the Statehouse. Taiwan last bought South Carolina farm goods in 1983.

It's the first time Taiwan has bought South Carolina corn and represents a doubling of the country's purchase of tobacco from the state two years ago.

''These purchases are extremely significant and beneficial to our balance of payments situation,'' Tindal said. ''Taiwan is one of very few of our agricultural trading partners which is deeply concerned over the balance of payments.

''A concerted effort by that country to lessen the trade deficit is obvious, and I find that kind of concern worthy of our continued support and friendship.''

A strong working relationship has existed between South Carolina and Taiwan for several years, including agricultural exchange programs, Tindal said.

''Many other states have been in competition with South Carolina, but previous ties have brought Taiwan back,'' said Tsum-Hsien Lin, director of the Atlanta office of the Coordination Council for North American Affairs.

The proposed contract calls for Taiwan to purchase 54,000 metric tons each of corn and soybeans and 980 metric tons of tobacco. It bought 54,000 metric tons of soybeans and 480 metric tons of tobacco in 1980.

''The expansion of the list of commodities is most encouraging,'' Tindal said.

''The purchases of the procurement mission will help the farmers of South Carolina, the citizens of Taiwan, and it will strengthen the ties that bind our countries.''