Farming equipment and buildings heavily damaged by Russian strikes and previous occupation in Ukraine’s southern region of Mykolvaiv, on Tuesday, Aug. 18, 2026. Strikes by both Moscow and Kyiv on shipping in the Black Sea leave farmers facing ruin and could cause another worldwide food shock. (Jedrzej Nowicki/The New York Times) By CARLOTTA GALL and KAMILA HRABCHUK It was a bumper harvest this year and barns in southern Ukraine are filled with great golden mounds of grain. Yet farmers in…