(Reuters) -Fertilizer maker CF Industries ( CF ) on Wednesday reported a 68% rise in third-quarter profit, aided by strong prices for nitrogen fertilizers.

Benchmark ammonia prices reached to about $530 per ton in September from $410 per ton at the end of June, aided by production shut-ins in Trinidad and Egypt.

Prices of natural gas, a key feedstock for nitrogen fertilizers, remained subdued during much of the reported quarter, helping CF Industries' ( CF ) margins.

The Northbrook, Illinois-based company reported net earnings of $276 million, or $1.55 per share, for the three months ended Sept. 30, compared with $164 million, or 85 cents per share, last year.