Grains inspectors who began a strike on Wednesday in Argentina's pivotal Rosario export hub will extend it for a second day if there is no progress on their demand for higher salaries, a senior union official said. Other unions are also threatening labor actions, risking disruptions in the shipping of grains from Argentina, the world's third largest exporter of corn and soybeans. The striking workers check the quality of grains before they are stored and then loaded onto ships. Strikes and labor disputes are common in Argentina, Latin America's No. 3 economy, which has one of the world's highest inflation rates and a depreciating currency that is eating into salaries. Argentine unions have hunkered down for a tough round of wage talks.