MarketWatch: CF Industries Holdings Inc. on Thursday said shipping reductions by Union Pacific Corp. rail lines would result in delays to nitrogen shipments. CF said it was notified by Union Pacific on April 8 that certain shippers would be mandated to reduce the volume of private cars on the railroad, effective immediately. The move will affect fertilizer shipments during the spring application season, CF said, adding that delayed deliveries may result in lower crop yields. CF said it ships to customers via Union Pacific rail lines primarily from complexes in Louisiana and Iowa. The rail lines serve agricultural areas in Iowa, Illinois, Kansas, Nebraska, Texas and California.