CHICAGO, Sept. 26 (Xinhua) -- Chicago Board of Trade (CBOT) agricultural futures dropped in the past week on a rising U.S. dollar, as investors flighted back to safety ahead of the U.S. election and a second wave of COVID-19 infections across parts of Europe.

Corn futures ended weaker as Chinese buying has slowed while the interior Midwest cash market is reflecting a sizable jump in new crop cash supplies. With U.S. domestic demand growth struggling on weak energy prices, there will be no shortage of U.S. cash corn without adverse weather in South America in 2020-2021. Chicago-based research company AgResource predicts negative seasonal trends until the U.S. harvest surpasses 60-70 percent.

Since 2013, spot CBOT corn futures have been bound to a range of 3.30 dollars to 3.90 dollars, with some rallies or breaks outside this range driven by supply.

It will be difficult for corn to sustain upward momentum as South American production expands, AgResource noted.

Wheat futures fell sharply this week. Russian cash wheat prices ended firm, but there's increasing evidence that surpluses in Northern Europe will undercut Russia on rallies. Southern Hemisphere supplies will be available to world marketplace beginning in November. The major exporter balance sheet is tight, but this year's massive increase in Australian export potential will prevent the need for supply rationing. U.S. wheat stocks will stay large.

Nevertheless, a medium-term uptrend line remains intact for wheat, AgResource noted.

Soybean futures were under pressure from the start of the week. U.S. farmers have been reported as moderate sellers on the rally as harvest gains speed, while funds booked profits ahead of the September Grains Stocks report.

Buying from Sinograin is winding down. Nevertheless, cumulative exports for the year are running at a record pace, while outstanding sales are also record large thanks to China, AgResource noted. The U.S. export rate is expected to hold at historic levels into early 2021.

AgResource estimated soybean harvest progress through Sunday in the United States will be 14-17 percent complete.