Corn and soybeans dropped, paring weekly gains, on speculation that drier, warmer weather will aid the harvests of bumper crops in the U.S., the world’s biggest grower. Wheat also declined. Midwest conditions the next 14 days will firm soils for heavy farm machinery, hastening field work after parts of the region got double the normal amount of rain the past two weeks, World Weather Inc. said in a report today. As of Oct.