The impact of the La Nina weather pattern that’s expected to roil global food markets in coming months is already showing up in parts of Brazil, the world’s biggest soybean exporter. In 20 years as a soybean farmer, Adriano Marco Vivian has never seen his fields so dry, with leaves burnt by excessive heat and lack of rain. La Nina can mean drought in many growing areas, including southern Brazil. “I believe around 70% of the yield potential has been lost,” Vivian, who is based in Parana, one of the top-producing states in the nation’s south, said in a telephone interview. “We haven’t seen widespread rains for more than 60 days,” said the farmer, who planted 700 hectares of soybeans in the state’s west. The picture is similar for all producers in the region, he said. Parched conditions and heat led Parana’s agriculture agency Deral to cut its estimate […]