Corn and soybean prices held steady as the US harvest began, with wheat prices increasing slightly after recent declines. A cargo ship carrying wheat left Ukraine, providing hope for easier grain shipping after a collapsed deal with Russia, but three Eastern European countries have banned food imports from Ukraine, potentially complicating overland grain exports. Concerns about a drop in Ukrainian supplies, along with large wheat exports from Russia and competition from Brazil's soybean crop, are likely to support prices in the short term.