By JEFF BURBRINK
Extension Educator, Purdue Extension Elkhart County

It is funny how things work. As the price of corn went up the last few years, the price of inputs such as seed, fertilizer and pesticides went up too. Now that corn prices are dropping, prices of inputs are not dropping significantly. To those who have to pay those bills, it’s really not all that funny.

If you are looking for a way to cut costs, one suggestion I have is to look at your fertilizer program. There are a surprising number of people applying phosphorus on fields testing high or very high for phosphorus that are not likely to get a return for their money.

Phosphorus is an important nutrient to corn, especially early in the growing season, particularly in no-till systems and when soils are colder than normal. But it can be an expensive nutrient to apply if there is no response expected.

A lot of money is spent on starter fertilizers containing both nitrogen and P. On high P testing soils, greater than 30 parts per million or 60 pounds per acre, nitrogen is the most important of these two nutrients, especially when high residue tillage systems are used.

When P is used on fields testing high or very high for P, you will often see a visual response to the added P fertilizer. Looks, however, are deceiving, because there is rarely a profitable response to the added phosphorus. In other words, the corn will look a little better, but the better looks do not translate to more money in your pocket at the end of the season.

It is surprising how many people have not soil tested their fields. What is the chance that your untested field is high in phosphorus levels and might not respond to an additional application? I can only guess, but in the past two years, I would estimate that only 5 to 10 percent of the soil tests passing across my desk had P levels below 30 ppm or 60 pounds per acre. Below that level, there is a very good chance your crops will respond favorably to some added P. To find out if your field is one of those fields, invest $15 to $20 per field to check the level of nutrients.