With high fuel prices, plan on higher fertilizer costs next year. In Minnesota, for example, these high prices may cause farmers to change how they traditionally use fertilizer nitrogen (N).

The production of anhydrous ammonia is directly linked to natural gas prices. Because anhydrous ammonia is the starting point for other fertilizers like urea, liquid N and ammonium nitrate, expect the prices of these to increase with the price of natural gas, says George Rehm, University of Minnesota soil scientist.

Growers have a few options to consider, including alternative N sources like ammonium sulfate or manure. Since the production of these is not directly linked to the production of anhydrous ammonia, they could be a more cost-efficient choice.

Another alternative is to use best management practices that will minimize the loss of applied N. Rehm says that fall application of N fertilizer is not a good option in eastern Minnesota. The large majority of the soils in the region are well drained and, understanding this property, there is ample time for preplant, sidedress or split applications of N as a substitute for fall applications.

Depth of application, split applications and matching the time of N application to soil texture are all things growers should consider, he adds. These can help determine when fall application is the most practical choice, or if there is a better alternative.

Estimates made by the Potash and Phosphate Institute (PPI), however, show that many growers in key production areas aren't replacing the soil nutrients removed by crops. If growers cut back now in order to save money, it could cost higher yields in the long run.

“The best and most accurate way for growers to know what nutrients will be needed by the crops they grow is to conduct a soil test,” says Paul Fixen, director of research at PPI. “This management tool allows growers to take much of the guesswork out of a soil fertility program and to better predict which nutrients are needed in certain fields.”