The most active corn contract for December delivery dropped 6 cent, or 1.68 percent, to 3.515 USA dollars per bushel.
"What would have been a phenomenal year for corn ten years ago now seems average".
"Tuesday's crop report data was collected well before Irma and was either finished before Harvey hit Texas or the data collection was impacted by Harvey, so the numbers being forecast are subject to change", he explained.
Based on conditions as of September 1, yields are expected to average 169.9 bushels per acre, up 0.4 bushel from the August forecast but down 4.7 bushels from 2016. Corn maturity was 4 percent, compared with 17 percent past year and a 21-percent average.
Ending stockpiles in 2016-2017 likely will be reported at 370 million bushels, unchanged from the prior month, while new-crop inventories are pegged at 442 million bushels, down from 475 million a month earlier, the analysts said.
Soybeans dipped for a fourth consecutive session - although losses were marginal - on expectation of a reduction in US yields, while corn fell for the first time in three sessions as markets await key supply-demand reports to be issued by the US Department of Agriculture (USDA).
The average soybean yield was forecast at 49.9 bushels an acre based on September 1 conditions, up 0.5 bushels from August but down 2.2 bushels from 2016.
The state experienced record-setting corn and soybean yields in 2016. Global corn stocks are estimated at 202.5 million tons, up 1.6 million tons when compared to August. USDA raised its export outlook for soybeans by 25 million bushels in 2017/18 and by 20 million bushels in 2016/17.