Winter wheat planting is almost complete with 95% seeded, and 84% emerged, one point ahead of average.
Weaker currencies of major grains exporters also make USA agricultural commodities more competitive.
Monday's CBOT open interest surged 23,214 contracts in corn, 3,582 in soybeans and 11,155 contracts in wheat on the lower trading session. Market anchored by ample USA supplies and the USDA's estimate of a record-high US corn yield.
Chicago Board of Trade corn futures ended higher Friday on short-covering and technical buying after the benchmark December contract stayed above a contract low set a day earlier, traders said.
The CME Group reported 137 deliveries against CBOT November soybean futures, which expire on Tuesday.
Flat to weaker in rangebound trade, hovering just above contract lows as the United States harvest progresses. Soybean production is expected to be down 1 percent to 252 million bushels, and sorghum production down 10 percent to 14.2 million bushels.