SINGAPORE — Noble Group Ltd.’s full-year profit fell 29% to $431 million, according to the company’s earnings statement released on Feb. 28.

For the fourth-quarter ended Dec. 31, 2011, profit dropped 57% with a narrowing of margins in the company’s agriculture, metals and minerals segments. 

Net income fell to $105.7 million in the fourth quarter from $247.5 million a year earlier. Sales for the quarter rose 15% to $20.1 billion.

Noble’s agriculture division posted a drop in operating income margin to 2.78% in the fourth quarter from 10.85% a year earlier. Grains and oilseeds crush margins were weak, and in some cases negative, throughout the year. The division still posted record revenue and volumes in the fourth quarter.

The sugar division also reported a quarterly record for revenue and volumes even as prices were volatile, helped by the integration of two newly acquired mills in Brazil, Noble said.