Deerfield, Ill. — Terra Nitrogen Co. LP reported net earnings of $129.8 million ($3.87 per common unit) on sales of $201 million for the fourth quarter ending Dec. 31, 2011, up from the year-ago $65.8 million ($2.61 per unit) on sales of $142.9 million. Ammonia and UAN average selling prices increased by 21 and 79 percent, respectively, while sales volumes were off 12 and 1 percent, respectively. Gas prices decreased 7 percent for both the quarter and year. Ammonia volumes were 84,000 st ($530/st) versus the year-ago 95,000 st ($439/st), while UAN volumes were 454,000 st ($343/st) versus the year-ago 459,000 st ($192/st). Full-year net income was $508 million ($15.33 per unit) on sales of $798.9 million, compared to 2010’s $201.6 million ($8.01 per unit) and $564.6 million, respectively. Ammonia and UAN prices increased 28 and 55 percent, respectively, while volumes were up 15 and 5 percent, respectively. Full-year ammonia volumes were 385,000 ($473/st), up from 2010’s 335,000 st ($369/st). UAN volumes were 2.05 million st ($299/st), up from 2010’s 1.96 million st ($193/st).