Chicago Board of Trade corn futures rose more than 4 percent for their largest daily gains in nearly six weeks on Monday, lifted by investor short covering ahead of a government crop report due on Wednesday, traders said.
Analysts expected the US Department of Agriculture in its monthly supply and demand update to cut estimates for US corn and soybean production after excessive rains earlier this summer reduced yield potential.
The daily gains in corn were largest since June 30, which saw the release of a USDA crop production and quarterly stocks reports.
Technical buying also was noted, with chart-based traders turning bullish after confirmation last week of a short-term low on corn futures. Front-month September corn futures hit a two-week high of $3.91-1/2 per bushel, climbing above both their 50- and 100-day moving averages after breaching their 10-day moving average on Friday.
Analysts polled by Reuters expected USDA later on Monday to cut good-to-excellent condition ratings for the US corn crop by 1 percentage point, to 69 percent.