News release issued April 29, 2001, effective immediately.
For media inquiries, contact Caroline Booth Lara, Communications Specialist, (580) 224-6379.
  email: cblara@noble.org

Why are Nitrogen Prices so High?

ARDMORE, Okla. -- Nitrogen fertilizer prices have been high for several months now. In some cases, the price has gone up 50 percent or more, but why is it increasing?

"The price of nitrogen fertilizers is directly related to the price of natural gas (methane). Manufacturing 1 ton of anhydrous ammonia fertilizer requires 33,500 cubic feet of natural gas. This cost represents most of the costs associated with manufacturing anhydrous ammonia," explained Eddie Funderburg, a soil and crop specialist with the Noble Foundation.

"When natural gas prices are $2.50 per thousand cubic feet, the natural gas used to manufacture 1 ton of anhydrous ammonia fertilizer costs $83.75. If the price rises to $7.00 per thousand cubic feet of natural gas, the cost of natural gas used in manufacturing that ton of anhydrous ammonia rises to $234.50, an increase to the manufacturer of $150.75."

Why is natural gas so heavily used in the manufacture of nitrogen fertilizers?

"First of all, nitrogen is all around us. In fact, the atmosphere is composed of 80 percent nitrogen," Funderburg said. "Unfortunately for our pocketbooks, it is not in a form plants can use."

Small amounts of nitrogen are converted to plant-available forms and sent to the earth in lightning strikes. Some is returned to the soil when rainfall washes pollutants out of the air. Free-living blue-green algae convert small amounts of atmospheric nitrogen to plant-available forms. Bacteria in legumes’ roots can convert atmospheric nitrogen to a plant-available form. Of all these mechanisms, only the one legumes use supplies enough plant-available nitrogen for high-yield agriculture.

"In 1910, scientists discovered that they could combine natural gas and the atmosphere at very high temperature (about 900 ºF) and pressure (between 200 and 1,000 atmospheres) to create anhydrous ammonia gas," Funderburg explained. "This technique is called the Claude-Haber ammonia synthesis process. Natural gas is used in the process two ways: to react with the atmosphere and supply hydrogen to the reaction, and create the high temperature and pressure necessary for the process to take place."

What if you use a form of nitrogen different from anhydrous ammonia? Why should your nitrogen fertilizer costs increase?

Most of the other popular forms of nitrogen fertilizer are made with anhydrous ammonia. Urea is formulated by a reaction between anhydrous ammonia and carbon dioxide at high temperature and pressure. Ammonium nitrate is formulated by combining anhydrous ammonia and nitric acid in a very corrosive manufacturing climate. Solution liquid fertilizers (28 to 32 percent nitrogen) are composed of one-half urea and one-half ammonium nitrate. In fact, it’s difficult to find a nitrogen fertilizer formulation that doesn’t have natural gas in its manufacturing process.

What can you do about high nitrogen prices? Should you discontinue using nitrogen fertilizers or reduce rates until the prices come down?

"One thing you can do is collect soil samples to see if they have high levels of residual nitrogen," Funderburg said. "If so, you can reduce or even eliminate the use of nitrogen fertilizers without reducing yield. The very wet winter we had this year makes it unlikely that large amounts of nitrogen carried over, but it doesn’t hurt to check."

To test for residual nitrogen, take both a 0- to 6-inch soil sample and a 6- to 12-inch sample.

"Other things you can do include realistically figuring your yield goals and fertilizing to meet these without using excessive amounts," Funderburg said. "Check your soil pH and apply lime if needed. Plants use nitrogen less efficiently in very acidic soils. Use the recommended rates of phosphorus and potassium. Plants use nitrogen more efficiently when these aren’t limited.

"Figure out what the increased nitrogen prices are going to mean to your bottom line," he concluded. .

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The Samuel Roberts Noble Foundation, headquartered in Ardmore, Okla., is a non-profit organization conducting agricultural, forage biotechnological, and plant biology research; providing grants to numerous non-profit charitable, educational and health organizations; and assisting farmers and ranchers through educational and consultative agricultural programs.

To learn more, check out the Noble Foundation Web site at http://www.noble.org.

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