Ever since fertilizer prices peaked last summer, the price of nitrogen and phosphorus has dropped. However, potassium prices have remained high, and it's causing some concern among grain crops producers.

"Last year, input costs rose as commodity prices climbed, but this year, commodity prices are not expected to go as high," said Lloyd Murdock, extension soils specialist for the University of Kentucky College of Agriculture. "If commodity prices remain low, producers are going to have to do a good job managing their fields to make money this year."

There's no clear reason why potassium costs have remained steady while other nutrient prices have dropped, but Murdock believes it may in part be due to the small number of potassium producers in North America.

He recently discussed possible strategies for approaching fertilizer applications this year with participants of the Integrated Pest Management Scout Training School held at UK's Research and Education Center in Princeton.

Murdock encouraged all producers to have a soil test done before applying fertilizers this spring. He recommended collecting at least one soil test for every 20 acres, but said producers with larger fields may want to consider grid sampling. Grid sampling divides a large field into several smaller plots and suggests collecting samples from each plot.

"A soil test may come back and show areas in a large field with abnormally low soil P and/ or K (phosphorus and/or potassium) and others with high levels," Murdock said. "If you know this beforehand, you can treat each zone differently."

Once producers have their soil tested, they can use the UK extension publication AGR-1 to determine the most cost-effective amount of fertilizer to apply to their fields. Considering the high price of fertilizers, Murdock said producers that have areas or fields with high phosphorus and/or potassium levels may want to skip any additional fertilizer applications this year to those fields in order to keep costs down.

If a soil test is low in phosphorus and/or potassium, producers need to apply the recommended fertilizer, regardless of the costs. Row fertilizing can help increase phosphorus and potassium efficiency while reducing the amount of fertilizer needed by at least a third and as much as a half.

AGR-1 is available online at http://www.ca.uky.edu/agc/pubs/agr/agr1/AGR1.PDF or at county offices of the UK Cooperative Extension Service.

Producers can bring soil samples to their local county extension office for testing. UK College of Agriculture soil specialists conduct the tests and then return the results to the county offices. Agriculture and natural resource agents can help producers understand the results of soil tests and address questions about soil testing.