Want to save on fertilizer? Run a soil test.
With fertilizer prices continuing their upward trend, a soil test is the best tool available to growers that can help them manage their crops while leaving more money in their pockets.
According to a USDA Economic Research Service report, less than 40 percent of corn acreage in the U.S. was soil tested in 2000 (the most recent data available) to make fertilizer management decisions. Robert Mullen, an Ohio State University Extension soil fertility specialist, speculates that number has increased, but those growers not utilizing soil testing are missing out on a huge money-saving opportunity, especially with today’s rising fertilizer prices.
There is value in the ability to measure the level of nutrients in the soil, such as soil pH, nitrogen, potassium and phosphorus, and from those numbers, make a more informed decision in fertilizer application that¹s good for the crops, as well as each grower-customer’s budget.
"You start by putting yourself in their shoes. I’m a producer. I get the soil analysis and I have this piece a paper. What matters on that sheet of paper and how do I use that information to make a decision?" advises Mullen.
"There is no cookie cutter recipe for fertility management because everyone has different soils and different cropping systems," he explains. "The idea is more of a case study approach. It’s to get them to think about the information in a different way and what they should go through when they start making decisions."
Mullen says that soil tests are an effective resource tool for fertility management because the analysis lets growers know which nutrients they need to invest in and which ones they can do without for a certain period of time.
Mullen points to phosphorus and potassium as an example. With both nutrients skyrocketing in price, a soil test would reveal how much potassium and phosphorus are currently available in the soil. Unlike nitrogen, phosphorus and potassium are not directly related to yield, so once they are present at adequate concentrations adding more would not result in additional productivity.
"Once you reach a certain concentration of potassium or phosphorus in the field, you don’t need to add any more fertilizer, and a soil test would be able to tell you that," says Mullen. "Without it, you may be paying for something you do not need."
Other things growers can determine from a soil test include soil pH, which reveals whether or not lime is needed; buffer pH, which indicates how much lime should be applied; and the amount of fertilizer necessary based on specific cropping systems.
(Source: The Ohio State University)