Chicago Board of Trade grain futures saw a slight decline on Tuesday, influenced by ongoing Russia-Ukraine peace talks and year-end trading. Soybean futures fell despite reports of China purchasing 136,000 metric tons of U.S. soybeans for the 2025-2026 marketing year, with market speculation that China aims to complete its buying commitments. Corn and wheat futures also closed lower, with wheat prices affected by concerns over substantial global supplies, including an increased Russian export forecast.