Corn and soyabean spot basis bids were unchanged to weaker on Monday at US Midwest elevators and processors as dealers continued to roll bids from May into July futures for both crops, merchants said. Producers and processors are tracking swollen tributaries after heavy weekend rains slowed barge traffic.

Farmers are also waiting for water in fields to recede so they can resume planting corn and soyabeans. US Department of Agriculture crop progress data on Monday showed corn 34 percent planted versus 17 percent a week ago. Soyabeans were 10 percent planted, versus 6 percent a week earlier, according to Monday's USDA data.

Copyright Reuters, 2017