Chicago wheat futures lost more ground on Friday with the market poised for its biggest weekly loss since late March as forecasts of dry weather across the U.S. grain belt are expected to boost the harvest.
Soybeans were set for a fourth weekly decline with improved planting weather in the U.S. Midwest and record South American supplies weighing on the market.
The Chicago Board of Trade most-active wheat contract is down 2.4 percent this week, set for its biggest weekly loss since the week of March 24.
Soybeans have fallen 1.4 percent so far this week, the fourth consecutive weekly loss, and corn has dropped more than 1 percent this week, the first weekly slide in six weeks.
Wheat is under pressure as forecasts of dry weather raised the prospect of an early start to the harvest of the U.S. winter crop.
"Kansas had faced very heavy rains but now June weather looks dry and that should be helpful for the wheat harvest," said one agriculture commodities analyst.
There is dryness expected for a week or so in the U.S. Midwest that will help soybean plantings accelerate."
There was additional pressure on soybean prices as a port strike this week in Argentina did not disrupt supplies.
Argentina's government has replaced striking sanitary inspection workers in the main agricultural port of Rosario, allowing shipments to resume, albeit with delays, the head of Rosario's port operators' chamber said on Thursday.