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College of Food, Agricultural, and Environmental Sciences


Get a Handle on Best Fertilizer Methods at Farm Science Review

September 6, 2006

LONDON, Ohio -- Corn growers may skimp on some fertilizer applications in favor of others as they ride the rollercoaster of fluctuating energy prices, potentially impacting their crop's performance. To maximize crop profits with few on-farm costs, Ohio State University and Purdue University soil specialists will help guide growers in making smart economic decisions during Farm Science Review.


Robert Mullen, an Ohio State University Extension fertility specialist with the Ohio Agricultural Research and Development Center, and Jim Camberato, a Purdue University soil fertility and plant nutrition specialist, will be on hand Sept. 21 during the Certified Crop Advisors event to provide participants with a better understanding of corn nitrogen rates for Ohio and Indiana.

"We'll be looking at the economics of fertilizer recommendations to help guide growers' decisions on what their rates should actually be," said Mullen, who also holds a partial OARDC research appointment. "It seems like everything is increasing and growers are always looking for ways to save money."

In order to cut costs, corn growers are axing the application of nutrients, such as phosphorus (P) and potassium (K), and cutting back on nitrogen (N) applications, said Mullen. The result is the potential for increased yield losses because the crop is not getting enough nutrients, especially in situations of unpredictable weather.

"Growers basically want to know what their risks are by lowering their nitrogen rates. And they want to know which nutrients to apply and which ones they can skip and still get a good yield," said Mullen. "Such management decisions are not as clear-cut as growers may think they are."

To aid growers in making such management decisions, Mullen has been educating them on the new tri-state (Ohio, Michigan, Indiana) fertilizer recommendations. The new system bases optimum nitrogen rates on the current price of fertilizer and the average price of corn, rather than based on maximum yield potential.

Other recommendations in determining what nutrients to add to a crop and how much include:

• Conducting a soil test to determine levels of phosphorus and potassium in the soil. "If a grower has enough P and K in his soil, then he knows he can invest in nitrogen applications. But if P and K is limiting, then he knows that he has to spread the finances among N, P and K," said Mullen.

• Establishing nitrogen reference strips and ramp strips. These strips are visual aids so a grower knows whether or not additional nitrogen must be applied to the crop in a particular field. A reference strip is several crop rows wide with full nitrogen rates (typically the swath width of an applicator), while the surrounding rows represent a grower's normal application practices. Ramp strips involve a gradual increase in nitrogen applications. "Both techniques are designed to allow growers a visual assessment of their nitrogen rate decision and determine if the year is such that additional nitrogen is necessary," said Mullen.

Farm Science Review is sponsored by Ohio State University Extension, the Ohio Agricultural Research and Development Center, and the academic units of the university's College of Food, Agricultural, and Environmental Sciences. Tickets are $8 at the gate or $5 in advance when purchased from county offices of OSU Extension or participating agribusinesses. Children 5 and younger are admitted free. Hours are 8 a.m. to 5 p.m. Sept 19-20 and 8 a.m. to 4 p.m. Sept. 21. For more information, log on to


Candace Pollock
Robert Mullen