Chicago Board of Trade (CBOT) grains futures closed mixed over the trade week which ended Sept. 8, as traders turn to technical selling ahead of Tuesday's U.S. Department of Agriculture (USDA) crop report.

The most active corn contract for December delivery added 1.5 cents weekly, or 0.4 percent, to 3.5675 dollars per bushel. December wheat delivery fell one cent weekly, or 0.23 percent, to 4.3775 dollars per bushel. November soybeans rose 12.5 cents weekly, or 1.32 percent, to 9.62 dollars per bushel.

Corn futures ended just marginally higher, and traded in a rather narrow range this week.

There's just not much enthusiasm to establish sizeable new positions ahead of next week's crop report, and more importantly ahead of actual harvest date - the point being the market is no more clear on corn yield than it was in August.

Otherwise, South America continue to ship record amounts of corn, a trend that will continue into mid-autumn.

Biofuel demand is rising, though, and global feed wheat is offered at a premium to corn, and is rising slowly amid seasonal trends and as the wheat market is finding better global demand interest.

It's likely that a seasonal bottom was scored last week, but a sideway or choppy pattern should be expected through the remainder of September.

Wheat futures ended low, and all classes of U.S. wheat likely scored their seasonal lows in late August.

Russian interior prices continue to drift lower as a record harvest overwhelms the pipeline there, but this is already largely reflected in Black Sea fob offers, and analysts doubt Russian wheat will be offered below 180 to 182 U.S dollars per ton.

The U.S. dollar's ongoing collapse, and general strength in other exporting currencies, continue to weigh on farmer profitability, with winter planting just around the corner. Australia's drought will worsen in the next two weeks, and the U.S. position in the world market is second only to Russia through November.

Analysts say a longer term bullish outlook requires adverse South American weather this winter, but on the margin they look for a modest rally into late year.

The soybean market posted good gains at the end of trading week. Fund short covering on concerns over limited August rains and a dry September forecast could lower yields, as well as steady demand from China supported the week's trade.

Chinese soybean imports in August were better than expected and indicate that the USDA is slightly underestimating old crop imports.

There is no indication that demand is slowing, and U.S. export sales last week were well above expectations. Commercial demand for exports should remain strong into the end of the year, but the trade's debate over yield and crop size will continue until harvest is in full swing.

The USDA will weigh in with their best guess on yield early next week, which will direct price trends into the end of the month.