CHICAGO, March 31 (Reuters) - Spot basis bids for corn delivered by barge to U.S. Gulf Coast terminals were firm on Monday on good demand from exporters and elevated freight rates, traders said.

* CIF soybean basis bids were flat to lower on seasonally slowing demand.

* Corn export shipments remained high, with weekly export inspections for the week ending March 27 reported above trade expectations at 1,614,406 metric tons, according to U.S. Department of Agriculture (USDA) data.

* The USDA said soybean export inspections last week totaled 793,250 tons, also above trade expectations. New soybean export sales, however, were slow as cheaper supplies were available from South America.

* Traders are monitoring news about reciprocal trade tariffs the U.S. President Donald Trump vowed to impose on April 2. Retaliation by importers of U.S. goods is expected to target U.S. agricultural products.

* U.S. barge freight rates have firmed in recent weeks due in part to shipping delays at locks under repair on the Mississippi River near St. Louis. BG/US

* CIF Gulf corn barges loaded in March were bid a penny higher at 79 cents over Chicago Board of Trade May CK25 corn futures. April corn barges were bid at 74 cents over futures, also up 1 cent.

* FOB export premiums for corn shipped from the Gulf in April were around 90 cents over futures, up 10 cents from late last week. Offers for May corn shipments were about 80 cents over futures, up 3 cents.

* CIF Gulf soybean barges loaded in March were bid at 77 cents over CBOT May SK25 soybean futures, down 2 cents. April soy barges were bid steady at 74 cents over futures.

* FOB export premiums for soybeans shipped from the Gulf in late April were around 92 cents over May futures. May offers were flat at 87 cents over futures.

(Reporting by Karl Plume; Editing by Shreya Biswas)

((karl.plume@thomsonreuters.com; +1 313 484 5285))

For displays of CIF basis, click on the codes in brackets:
U.S. CIF Gulf soybeans GRYM
U.S. CIF Gulf corn GRYN
U.S. CIF Gulf SRW wheat GRYO
U.S. CIF Gulf HRW wheat GRYP
For displays of FOB basis, please click on the following codes in brackets:
U.S. FOB Gulf corn GRZC
U.S. FOB Gulf soybeans GRZD
U.S. FOB Gulf SRW wheat GRZE
U.S. FOB Gulf HRW wheat GRZF

LINKS Corn prices page:   cpurl://apps.cp./cms/?pageid=corn-cash-market
Wheat prices page:  cpurl://apps.cp./cms/?pageid=wheat-cash-market
U.S. barge freight                  BG/US
U.S. export sales estimates         USDA/EST
U.S. grain export summary           GRA/U
Brazil soybean export prices        SYBS
Brazil corn export prices           SYBX
Argentina grain prices              GRA/ARG
Russia grain prices                 GRA/RU